BEGIN:VCALENDAR VERSION:2.0 X-WR-CALNAME:Aerocenter Seminars PRODID:-//Apple Computer\, Inc//iCal 2.0//EN X-WR-RELCALID:8B3BF30A-979B-4457-A7AC-6AB6DFF592DF X-WR-TIMEZONE:US/Eastern CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VTIMEZONE TZID:US/Eastern LAST-MODIFIED:20050903T143939Z BEGIN:DAYLIGHT DTSTART:20050403T070000 TZOFFSETTO:-0400 TZOFFSETFROM:+0000 TZNAME:EDT END:DAYLIGHT BEGIN:STANDARD DTSTART:20051030T020000 TZOFFSETTO:-0500 TZOFFSETFROM:-0400 TZNAME:EST END:STANDARD END:VTIMEZONE BEGIN:VEVENT LOCATION:Bldg 33 Lobby DTSTART;TZID=US/Eastern:20050104T110000 SUMMARY:AeroCenter Poster Session: Informal poster session with 10 presenters DESCRIPTION:Bian/Eck/Ichoku/Kim/Levy/Li/Tao/Welton/Wen/Wong END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 H114 DTSTART;TZID=US/Eastern:20050107T090000 SUMMARY:Aerosol Update: Highlights by AeroCenter Researchers in 2004 - Top 10 AeroCenter Papers in Past 5 Years: DESCRIPTION:12 short talks highlighting the most exciting science produced by AeroCenter researchers in 2004 (part A). Followed by the 10 most highly cited AeroCenter papers of the past 5 years (part B). END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 H114 DTSTART;TZID=US/Eastern:20050111T110000 SUMMARY:Brent Holben: UAE^2 Report DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 H114 DTSTART;TZID=US/Eastern:20050125T110000 SUMMARY:Yoram Kaufman: Can MODIS derive anthropogenic aerosol? DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 H114 DTSTART;TZID=US/Eastern:20050126T103000 SUMMARY:Gera Stenchikov: Volcanic Aerosols and Climate DESCRIPTION:ABSTRACT\nVolcanic eruptions are one of the most important causes of climate variability on one-two year time scale. Strong volcanic eruptions impact the Earth's climate for a few years because volcanic aerosols cool the surface and the troposphere reflecting solar radiation and warm the lower stratosphere, absorbing thermal IR and solar near-IR radiation. Radiative impact of volcanic aerosols also produces changes in atmospheric circulation forcing a positive phase of the Arctic Oscillation (AO) and causing counterintuitive boreal winter warming in middle and high latitudes over Eurasia and North America. Because of their various impacts on climate system volcanic eruptions play a role of natural tests of multiple feedback mechanisms and "high-frequency" climate sensitivity. Although climate perturbations caused by individual volcanic eruptions last for a few years, the climate impact of a series of strong eruption could affect climate for decades. E. g., the climate of the second part of 20th century was significantly affected by strong volcanic eruptions of Agung in 1963, El Chichon in 1982, and Pinatubo in 1991. It is very important that this period is partly covered by satellite observations that provide invaluable information for formulating and testing modeling studies. We will report on analysis of results from the 1991 Mt. Pinatubo case-studies and the late 19th-20th century GFDL IPCC experiments to investigate the effect of major volcanic eruptions on the temperature and circulation of the stratosphere and troposphere. After such eruptions we see tropical stratospheric warming, high-latitude stratospheric cooling and global-mean tropospheric cooling. Observed and simulated temperature responses are affected by the Southern Oscillation (SO), the stratospheric Quasi-Biennial Oscillation (QBO), and associated polar ozone depletion that have to be accounted for. We reproduced in simulations a positive winter response of the Arctic Oscillation (AO) forced by volcanic aerosols, and studied mechanisms of AO sensitivity. It has been previously assumed that volcanoes force a positive phase of the AO because of strengthening of the equator-to-pole temperature gradient in the lower stratosphere caused by aerosol radiative heating in tropics. This mechanism is based on the strong feedback between polar NH winter vortex and vertical propagation of planetary waves with stronger vortex reflecting planetary waves that makes the vortex more strong and stable. We also have shown that tropospheric cooling caused by volcanic aerosols can affect storminess and generation of planetary waves in the troposphere. It tends to decrease a flux of wave activity from the troposphere into the stratosphere accelerating the polar vortex and eventually causing a positive phase of the AO. Polar ozone depletion caused by heterogeneous chemistry tends to cool polar stratosphere in spring strengthening polar vortex and delaying final warming. QBO modulates the strength of polar vortex weakening and destabilizing the polar vortex in its easterly phase and making it stronger and more stable in its westerly phase. We showed that the aerosol perturbations to the tropospheric winter circulation are affected significantly by the phase of the QBO, with a westerly QBO phase in the lower stratosphere resulting in an enhancement of the aerosol effect on the AO. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 H114 DTSTART;TZID=US/Eastern:20050202T153000 SUMMARY:Ilan Koren (Climate and Radiation Branch Seminar): Cloud aerosol interaction - the next generation DESCRIPTION:Changes in the cloud droplet properties may induce changes in larger scales. Rain suppression or delay will allow a development of stronger updrafts. Smaller droplets driven by stronger updrafts may freeze on lower temperatures releasing the freezing latent heat higher in the atmosphere, hence further enhancing the convection. Stronger convection will create higher clouds, larger ice anvils and different rain patterns. We are seeing such effects by using large statistics of 1km resolution MODIS data over the Atlantic. The net aerosol effects are isolated from the meteorology by several tests and the orthogonal component is estimated by regression. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 F225 DTSTART;TZID=US/Eastern:20050204T110000 SUMMARY:Olga Kalashnikova: Implications of new non-spherical optical dust models for MISR DESCRIPTION:Satellite measurements provide important tools for understanding the effect of mineral dust aerosols on past and present climate and climate predictions. However the quality of satellite aerosol retrievals depends critically upon the modeling accuracy of the aerosol optical properties, which is a function of particle morphology, mineralogy, and state of mixing. Multi-angle instruments such as Multi-angle Imaging SpectroRadiometer (MISR) provide independent constraints on aerosol properties based on their sensitivity to the shape of aerosol scattering phase functions. The current MISR operational retrieval algorithm (version 16 and higher) was modified by incorporating new non-spherical dust models that we developed based on data from Individual Particle Analysis of naturally occurring airborne dust samples. We will present selected examples of MISR version 16 retrievals over AERONET sunphotometer land and ocean sites during the passage of dust fronts. Our analysis shows that during such events MISR retrieves Angstrom exponents characteristic of large particles, having little spectral variation in extinction over the MISR wavelength range (442, 550, 672 and 866 nm channels), as expected for dust particles. The retrieved fraction of non-spherical particles is also very high, a quantity not retrieved by satellite instruments having only nadir-viewing cameras. Our comparison of current (version 16) MISR-retrieved aerosol optical thickness (AOT) with AERONET instantaneous AOT shows better coverage and stronger correlations than when making identical comparisons with previous AOT retrievals (version 15). The MISR algorithm successful mixtures include a non-spherical dust component with high frequency in retrievals over dark water and slightly lower frequency over land. MISR selection frequencies of non-spherical dust models also decrease in dusty regions affected by smoke and pollution. Having non-spherical particle optical models that realistically represent particle shapes may be important for many other Earth and planetary science remote sensing applications. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 F225 DTSTART;TZID=US/Eastern:20050208T110000 SUMMARY:Menglin Jin: Urban Aerosols and Their Variations with Clouds and Rainfall: A Case Study for New York and Houston DESCRIPTION:MENGLIN JIN, J. MARSHALL SHEPHERD, AND MICHAEL D. KING\n\nDiurnal, weekly, seasonal, and interannual variations of urban aerosols were analyzed with an emphasis on summer months using 4-years of the National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) observations, in situ AErosol RObotic NETwork (AERONET) observations, and in situ EPA PM2.5 data for one mid-latitude city (New York) and one sub-tropical city (Houston). Seasonality is evident in aerosol optical thickness measurements, with a minimum in January and a maximum in April to July. The diurnal variations of aerosols, however, are detectable but largely affected by local and regional weather conditions, such as surface and upper-level winds. On calm clear days, aerosols peak during the two rush hours in the morning and evening. In addition, corresponding cloud properties observed from MODIS and rainfall measurements from NASA's Tropical Rainfall Measuring Mission (TRMM) demonstrate an opposite phase to the seasonality of aerosols. Furthermore, the anthropogenic-induced weekly cycles of aerosols and clouds are analyzed, which by themselves are weak as the anthropogenic signal is mixed with noises of natural weather systems. These analyses suggest spatial and temporal aerosol variations are important in order to fully simulate urban environment in a climate model. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 F225 DTSTART;TZID=US/Eastern:20050222T110000 SUMMARY:Peter Colarco: Smoke Gets in Your Eyes DESCRIPTION:During spring 2003 intense fires burned across the boreal forests in eastern Russia. Smoke from these fires was transported widely throughout the northern hemisphere. In particular, high altitude smoke plumes from these fires were observed over the ARM measurement site in Oklahoma between May 27 - 29, 2003. Using MODIS firecount data and trajectory calculations we determine the timing, origin, and injection altitude of these smoke plumes. This analysis is used to initialize an aerosol transport model, which here is compared to available satellite observations from TOMS and MODIS, as well as ground-based remote sensing datasets such as MPLNET and AERONET. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 F225 DTSTART;TZID=US/Eastern:20050308T110000 SUMMARY:Huisheng Bian: Relationships between CO and aerosols DESCRIPTION:Global CO simulation has been implemented in GOCART. In this talk, we will first evaluate three years (2000-2002) tagged CO and fine mode aerosols from GOCART against integrated measurements from surface (CMDL/CO and AERONET/aerosol), satellite (MOPITT/CO and MODIS/aerosol), and aircraft (CMDL/CO). The uncertainties of CO anthropogenic and biomass burning emissions in current inventories and their influence on atmospheric CO distributions are discussed. We will then look at the correlations between CO and fine mode aerosols over global, regional, and local regions by comparing and contrasting their distributions. The correlations reveal the general features of pollutant loading and the influence of atmospheric transport, transformation, and depositions. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 H114 DTSTART;TZID=US/Eastern:20050310T153000 SUMMARY:Zev Levin: On the interactions of mineral dust and sea salt with clouds; some results from the MEIDEX campaign DESCRIPTION:ABSTRACT\nThe vertical distribution of the physical and chemical properties of aerosol particles during a dust storm in the eastern Mediterranean will be discussed. The data was obtained from airborne measurements during the Mediterranean Israeli Dust Experiment (MEIDEX). Using these data as input into a cloud model reveal the potential role of GCCN and of IN in the development of clouds and rain in the Mediterranean region. The lecture will briefly cover the objectives of MEIDEX, the instrumentation on board the Airplane, the results of the measurements and the results of the model simulations. If time permits, a short presentation will be given on the MEIDEX observations of Sprites and Elves on board the Columbia Space shuttle in its final and tragic mission. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 H114 DTSTART;TZID=US/Eastern:20050316T153000 SUMMARY:D. Allen Chu (Climate and Radiation Branch Seminar): Air Quality to Climate Change: INTEX/NEAQS/ICARTT Perspectives DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 F225 DTSTART;TZID=US/Eastern:20050322T110000 SUMMARY:John Ondov: Emission Rates from individual Sources and their contributions to ambient PM using a Pseudo-Deterministic Receptor Model and highly time-resolved pollutant measurements DESCRIPTION:Thirty-minute metals measurements have been made at 5 locations, including three EPA "Supersites," using the University of Maryland Semicontinuous Elements in Aerosol Sampler (SEAS). These data contain a wealth of inherent information on the location of sources, e.g., observed plume with varies with distance and, more importantly, combined with meteorological data, they reveal the direction of the source when the time-scale for changes in wind direction are comparable to the measurement periods. To better exploit these data, we have been developing a new pseudo-deterministic hybrid receptor model (PDRM) for determining emission rates of pollutants from individual sources. In PDRM the basic factor model terms are interpreted as the products of pollutant (i) emission rates (ERi) and meteorological dispersion factors (X/Qj) for stationary sources (j) known to be located in the modeling domain. The Gaussian plume model is used to constrain solutions to the X/Qjs by appropriately filtering contributions from sources according to their angle with respect to prevailing winds. Model outputs are i) average ERis for each source for the modeling period, ii) time dependent X/Qjs, and iii) resolved source contributions to ambient concentrations. Accurate solutions are obtained with data collected in <24 hours. PDRM successfully predicted SO2 emission rates in the Tampa Bay Regional Aerosol Chemistry Experiment and more recently has been applied to Pittsburgh, a domain characterized by rough terrain. The underlying measurements and the new PDRM model and its applications to BRACE and Pittsburgh will be described.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room H114 DTSTART;TZID=US/Eastern:20050323T110000 SUMMARY:John Reagan: AERONET Based Aerosol Models and Their Use in a Constrained Ratio Approach for Spaceborne Lidar Aerosol Retrievals DESCRIPTION:In the absence of auxiliary optical depth/transmittance information, or self-determination of same for specialized observing situations, aerosol backscatter and extinction profiles cannot be retrieved from lidar observations along a single direction without an assumption linking aerosol extinction and backscatter (i.e., the aerosol extinction-to-backscatter ratio, or aerosol lidar ratio, Sa). For the mid-visible region (~550 nm), Sa typically ranges between ~20 to 80 depending on aerosol type. To first order, Sa is spatially fairly constant over several to tens of km in well mixed boundary layers, elevated transport layers and the like. In this seminar, a revised table look-up approach that incorporates two notable revisions for improved Sa selection will be presented. Firstly, a more bounded set of Sa values, both for 532 nm and 1064 nm, which are representative of a definitive set of aerosol types/models, are determined from an extensive analysis of the AERONET data base. Secondly, use of an accompanying set of key spectral ratio parameters (i.e., dual wavelength, 532 nm to 1064 nm, ratios of backscatter, extinction and Sa), which are also derived from the AERONET data, offers an additional way to bound the lidar aerosol retrievals. With these two revisions, aerosol retrievals can be obtained subject to the constraints that the lidar data yield retrievals with spectral ratio parameters consistent with a given aerosol model (or models). Simulations and LITE & GLAS data analysis examples will be presented to demonstrate the efficacy of this Constrained Ratio Aerosol Model-fit (CRAM) retrieval approach. END:VEVENT BEGIN:VEVENT LOCATION:H114 DTSTART;TZID=US/Eastern:20050324T153000 SUMMARY:Ralph Kahn (Laboratory for Atmospheres Seminar): What MISR Multi-Angle Imaging Contributes to Our Picture of Atmospheric Aerosols? DESCRIPTION:With contributions from:\nJ. Martonchik, D. Diner, O. Kalashnikova, W-H. Li, W. Abdou, W-T. Chen, B. Gaitley and the MISR Team \n\nAerosols generally do not remain in the atmospheres long enough for global mixing, and many respond to changes in relative humidity and other factors, so their properties and amounts vary on many space and time scales. However, aerosols contribute to direct radiative forcing, and indirectly by affecting cloud properties, to a degree that must be considered when modeling climate on global, and especially on regional scales. Uncertainties in aerosol distributions and details of their impacts are large enough to compete with other key indetermacies in setting current limits on climate modeling predictions (e.g., IPCC, 2001).\n\nNo single observational technique currently available or conceived is capable of measuring all the required aerosol properties with sufficient frequency and detail to address climate-modeling needs alone. But the combination of satellite, in situ, and surface monitoring capabilities offers that possibility in the foreseeable future. Satellites provide coverage to this measurement suite, and their contribution depends on the accuracy, completeness, and specificity of their aerosol products. \n\nThe Multi-angle Imaging SpectroRadiometer (MISR) instrument, flying aboard the NASA Earth Observing System?€™s Terra satellite, acquires nine along-track images at view angles ranging from +70Â? through nadir to ?€“70Â?, in each of four wavelengths, near-simultaneously. The instrument systematically covers air-mass-factors between one and three, and in mid-latitudes, samples scattering angles extending from about 60Â? to 160Â?. These data contain information about particle amount, size, and shape. Large air-mass-factors provide sensitivity to optical depth even for very thin hazes. Data are acquired at spatial sampling frequencies up to 275 m, and global coverage is obtained about once per week. \n\nWe have demonstrated the ability to reliably retrieve aerosol optical depth over bright surfaces, such as desert dust source regions, and to accurately retrieve thin aerosol haze optical depth over land and water, filling important gaps in the global-scale information provided by other instruments. We have also established retrieval sensitivity to particle size and shape, making it possible to separate mineral dust from pollution and other common aerosol types. This improves our ability to track aerosol air mass types over large distances, and gives added weight to detailed particle microphysical properties that may be measured in situ at single points during the life history of an air mass. Routinely derived plume elevations from MISR stereo observations in aerosol source regions offer constraints on particle injection height that, along with source strength, are the key initial conditions for modeling aerosol transports.\n\nThis talk will summarize both the strengths and limitations of the MISR aerosol products, and how they may fit in with other satellite, in situ, and surface measurements, to advance our global picture of atmospheric aerosols. END:VEVENT BEGIN:VEVENT LOCATION:H114 DTSTART;TZID=US/Eastern:20050331T120000 SUMMARY:Lackson Marufu (Atmospheric Chemistry and Dynamics Branch lunch talk): Blackout DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 F225 DTSTART;TZID=US/Eastern:20050405T110000 SUMMARY:Yogesh Sud DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 F225 DTSTART;TZID=US/Eastern:20050419T110000 SUMMARY:Santiago Gass?? DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:F225 DTSTART;TZID=US/Eastern:20050503T110000 SUMMARY:Vanderlei Martins: TBD DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:E125 (note: room change!) DTSTART;TZID=US/Eastern:20050517T110000 SUMMARY:Richard Calabrese: CFD Simulation of Virtual Impactors for Aerosol Sampling DESCRIPTION: The goal of our work is to employ Computational Fluid Dynamics (CFD) simulations to design more efficient virtual impactors for concentrating and collecting biological aerosols. To begin the process, simulations were performed with the Fluent CFD code for the slit geometry of Sioutas & Koutrakis (1994), who measured collection efficiency and wall loss for sub-micron aerosols. For this high-speed impactor, the steady, three dimensional RANS equations were solved for both incompressible and compressible flow to predict the turbulent velocity field. Particle trajectories were then calculated using a one way coupling technique with two different Lagrangian tracking schemes. The first uses only the mean velocity field (tracking relative to streamlines). The second uses a Random Walk model (stochastic approach) to account for the effect of turbulent velocity fluctuations. Since fluctuations can significantly affect particle trajectories and wall loss, it is important to realistically predict turbulence levels. As a result, two closure schemes were considered. These are the standard k-ε model, which requires an assumption about how the turbulent kinetic energy yields the individual components of root mean square (rms) turbulent velocity, and the more computationally intensive Reynolds stress model (RSM), which directly yields the rms velocities.\n The results of our parametric study show that it is necessary to account for the compressible nature of the flow, and that the choice of turbulence model significantly influences predicted collection efficiency and wall loss for both tracking schemes. The standard k-ε model yields unrealistic results for the mean velocity profile in the separation region and does not account for turbulence anisotropy. The RSM model yields intuitively acceptable results that are more inline with the experimental data, but under-predicts turbulence levels. Because of this, collection efficiencies and wall loss based on stochastic tracking did not differ substantially from those for mean velocity tracking.\n Our results indicated that calculated particle trajectories could be significantly influenced by the choice of velocity interpolation scheme and drag law, requiring options not available in the Fluent code. A third order accurate interpolation scheme was developed which accepted Fluent fluid velocity fields. This algorithm was employed in a second parametric study in which several drag laws were used. These accounted for fixed and pressure dependent slip, non-Stokes (high Reynolds number) drag and compressibility effects (high Mach number). It was found that it was necessary to account for these non-Stokesian effects to bring predicted collection efficiency and wall loss for sub-micron particles more in line with the literature data.\n We conclude by discussing the limitations of the aforementioned work, and by presenting some preliminary simulations to capture the transient nature of the flow structures present in virtual impactor devices. END:VEVENT BEGIN:VEVENT LOCATION:F225 DTSTART;TZID=US/Eastern:20050531T110000 SUMMARY:Everette Joseph: Aerosol-Climate Studies at Howard: Radiative Impact of Saharan Dust During AEROSE 2004, and Retrievals of Cloud and Aerosol Properties at Beltsville DESCRIPTION:The 2004 Aerosol and Ocean Science Expedition (AEROSE) was a multidisciplinary oceanographic field campaign conducted onboard the NOAA Ship Ronald H. Brown (NOAAS RHB) in the tropical North Atlantic Ocean from 29 February to 26 March 2004. The overall mission objectives were to: characterize the impacts and microphysical evolution of Saharan dust aerosol transport across the Atlantic Ocean; Obtain bio-optics and oceanographic observations to assist in studying the effect of dust on the marine boundary layer, characterizing water masses throughout the transects, and investigating upwelling conditions off the Northwest coast of Africa; and provide visible and infrared (IR) measurements and analysis for validation of products from AIRS, and AVHRR/3.\n\nPreliminary analysis of aerosol optical depth derived from sun photometers, solar and IR fluxes from radiometers, meteorological measurements from balloon borne soundings, and calculations of radiative heating profiles during dust events and in pristine conditions will be discussed.\n\nA brief overview will also be given of a newly developed facility for atmospheric measurement at Howard’s Beltsville campus, and the research that is being conducted there. Particular attention will be given to the system for retrieval of cloud and aerosol properties. \n END:VEVENT BEGIN:VEVENT LOCATION:F225 DTSTART;TZID=US/Eastern:20050614T110000 SUMMARY:Charles Gatebe: Spectral, Angular and Vertical Characterization of Aerosols for Radiative Properties DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:F225 DTSTART;TZID=US/Eastern:20050628T110000 SUMMARY:Yogesh Sud: TBD DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20050906T110000 SUMMARY:Lorraine Remer and Mian Chin: Model and satellite retrieval for global aerosol: What can and can't we do? DESCRIPTION:In a spirited debate we will discuss the strengths and weaknesses of global transport models and satellite sensors to represent the truth of the global aerosol system. Naturally focusing on the GOCART model and the MODIS aerosol retrieval, we will show side by side comparisons of results, question each other's assumptions and try to agree upon a true state of the art. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20050913T110000 SUMMARY:Allen Howard, Jr.: Elastic Backscatter LIDAR Retrieval of Aerosol Cloud Parameters DESCRIPTION:West Desert Test Center (WDTC) at Dugway Proving Ground uses measurement,\nmodeling and simulation capabilities to characterize and referee customer standoff\nbiological and chemical detection systems. An in-house LIDAR (Light Detection and\nRanging) capability is important for ground-truth evaluation of standoff detectors\nand support of related time dependent aerosol cloud tracking and modeling. In this\nwork, the primary goal is to estimate aerosol particle size distribution as a function of\nposition and time. The hardware and software components of the paramter retrieval\nhave both gone through several improvements. My contribution to the algorithms to\nestimate aerosol parameters is not complete. At this stage in the development, all\nprocessing is based upon computer simulations of backscattered power.\nA closed aerosol cloud edge is generated by low-pass filtering a random sequence of\nedge radii. This edge is then translated, stretched and rotated resulting in a prescribed\ncentroid, aspect ratio and orientation. The cloud is then populated with spherical\nparticles defined by a joint aerosol cloud distribution function N(a, r), where a is the\nparticle radius and r is the position vector of the particle. Simulated backscattered\npower, including detector noise, is computed at two or three laser wavelengths is\npredicted by a form of the LIDAR equation. The retrieval process is in two stages.\nStage one estimates volume extinction and backscatter coefficients at each wavelength\nand discrete position within the cloud using an iterative Fernald recursion method.\nThe method accounts for background. The second stage solves the coupled first\norder integral equations at each discrete point within the LIDAR cloud sweep for\nthe underlying aerosol parameter distribution. Preliminary numerical results of the\nvarious stages of the simulation are given indicating the utility of the method. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20050927T110000 SUMMARY:Charles Ichoku: Potential of improving smoke source characterization with satellite fire radiative power measurements DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20051011T110000 SUMMARY:Myeong-Jae (MJ) Jeong / Zhanqing Li: Separating the effects and artifacts of cloud, humidity and dynamics on aerosol retrievals DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20051025T110000 SUMMARY:IPCC review discussion forum DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20051108T110000 SUMMARY:Rob Levy: Developing an improved algorithm for deriving aerosol over dark land surfaces from MODIS DESCRIPTION:The MODerate-resolution Imaging Spectro-radiometer (MODIS) has been successfully retrieving aerosol properties over dark land surfaces, beginning in early 2000 from Terra and from mid 2002 from Aqua. The aerosol optical depth (AOD) has been compared to ground based AERONET data, and has been validated to known errors bars, but tends to overestimate AOD in clean conditions and underestimate very heavy aerosol. In addition, the fine mode weighting (FMW) of the AOD is accurate only under certain conditions. These biases arise from at least three sources: 1) errors in assumed surface reflectance, 2) errors in assumed optical properties of aerosol, and 3) assumption that aerosol is transparent in the MODIS 2.1 micron channel. During the last year and half, we have attacked all three sources of error. By improving our assumptions of surface reflectance, we have reduced the positive bias in clean conditions. We have used the multi-year AERONET aerosol climatology to revise the assumed aerosol optical models, thereby improving high AOD retrievals. Finally, we developed a new algorithm that simultaneously inverts the MODIS channels (0.47, 0.66 and 2.1 microns), removing the necessary assumption that aerosol is transparent in the IR. Results are preliminary, but suggest that both the AOD and FMW products will be improved. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20051122T110000 SUMMARY:Mark Schoeberl: How to develop a space mission (Do's and Don'ts) DESCRIPTION:Having worked on an ESSP proposal (that lost), having gone through IMDC more than once and having reviewed many ESSP candidates, I am somewhat qualified to give advice on developing space missions. If you are thinking of developing a concept, this talk should be helpful. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20051201T110000 SUMMARY:Stefan Kinne DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Lobby DTSTART;TZID=US/Eastern:20051213T110000 SUMMARY:AGU posters DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060110T110000 SUMMARY:Eric Vermote: MISR-MODIS fusion for deriving the aerosol absorption DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060124T110000 SUMMARY:Xiaowen Li: Aerosol impacts on Precipitation Processes: A Modeling Study DESCRIPTION:The Goddard Cumulus Ensemble (GCE) Model is used to study the indirect aerosol effects on deep precipitation systems. The bin microphysical scheme in the cloud model allows for explicit simulations of the cloud nucleation process and the interactions of cloud particles with other hydometeor types. It is shown that increasing aerosol concentration can change both the microphysical and dynamical structures of a precipitation system. The sensitivities of aerosol concentration as CCN are also highly case dependent. Possible model validations and improvements through collaborations between modeling and observation studies will also be discussed. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060126T140000 SUMMARY:Fabien Waquet: Contribution of multispectral (0.49-2.2 µm) and polarized measurements for aerosol characterization DESCRIPTION:The radiative effect of aerosol constitutes a major source of global climate change uncertainty. Over land, where the main aerosol sources are located, the knowledge of the surface contribution constitutes the most important difficulty in aerosol remote sensing. This study mainly focuses on the development of a new approach to retrieve aerosol properties over land, based on the use of polarized measurements extended in the middle-infrared. This method is based on the assumption that the polarized surface contribution is neutral from the visible to the middle-infrared (0.67-2.2µm). At 2.2µm, the atmospheric contribution is minimized, then, the surface contribution should be directly measured.\n\nTo improve such a new approach, a multispectral airborne polarimeter, called MICROPOL, has been developed at the laboratoire d’optique atmosphérique in Lille (LOA) with the support of the French space agency (CNES). This instrument participated to several aircraft campaigns over land (north of France, pollution study and surface investigation) and ocean. After a first step of instrumental characterization, I developed for this instrument an algorithm based on the MODIS approach (Tanré et al., 1997.) A comparison with ground-based measurements (AERONET/PHOTONS) enabled to validate both instrument and algorithm. Over the Mediterranean Sea, the MICROPOL instrument was associated with the airborne lidar LEANDRE. The combination of passive and active measurements was used to investigate the vertical and horizontal properties of a desert dust plume (Waquet et al, 2005.)\n\nOver land, a new algorithm based on the polarized measurements performed at 2.2 µm has been developed and appreciated. A surface study confirmed a weak spectral dependence of the surface contribution from the visible to the middle-infrared. Then the surface contribution in each channel was estimated according to measurements at 2.2µm. A path radiance technique was also considered (Kaufman et al, 1997.) The comparison of both approaches showed that, in the specific case of anthropogenic aerosol observations, only the new polarized approach enables to retrieve aerosol optical thickness and size parameter over both urban and natural surfaces. This study constitutes a crucial step of validation in the frame of the development of a new spatial polarimeter including multispectral and multidirectional capacities, based on the POLDER concept (OSIRIS). END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room H114 DTSTART;TZID=US/Eastern:20060130T110000 SUMMARY:Paulo Artaxo: TBA DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060203T110000 SUMMARY:Michael Schultz: Why do direct aerosol forcing estimates in global models differ? Lessons from the AeroCom intercomparison DESCRIPTION:Estimating the direct radiative forcing from the aerosol involves assumptions on the aerosol life cycle, optical properties and the forcing efficiency.\n\nRecent observation based estimates suggest a substantially larger cooling effect due to anthropogenic aerosols than most of the global aerosol models simulate.\n\nThe discrepancy is discussed using an analysis of the model output assembled in the aerosol model intercomparison AeroCom. A sensitivity analysis suggests important contributions of direct aerosol effects in cloudy skies, due to the interaction of carbonaceous aerosols with the cloudy-sky radiation fields.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room H114 DTSTART;TZID=US/Eastern:20060210T130000 SUMMARY:Goddard Annual Aerosol Update DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060214T110000 SUMMARY:Ray Hoff: 3D Air Quality System (3D-AQS) DESCRIPTION:Over the last thirty years, we have come to understand that the atmosphere is quite dynamic, leading to transport of pollutants over wide areas including continent-to-continent motions. Only recently, however, have regulatory agencies paid particular attention to local versus long-range transport. In order to understand how to discriminate between these sources, measuring and modeling the vertical third dimension needs to be understood to assess source/receptor relationships. \n\nOur group has combined lidar at UMBC with measurements from spaceborne platforms to provide views of aerosol pollution in ways that weren't possible even ten years ago. As a result of the initial lidar/AOD work, we have recently been funded to create a Three Dimensional Air Quality System (3D-AQS) under the ROSES Decisions solicitation. This talk will review some of those studies on air pollution in the Baltimore-Washington region and describe the work to be conducted under 3D-AQS. We see this as the beginning of a new vision for NASA, NOAA, EPA and the Centers for Disease Control to combine systems under the Global Earth Observing Systems of Systems (GEOSS) approach to better determine the effects of aerosols on human health.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060228T110000 SUMMARY:Xiaoyang Zhang & Shobha Kondragunta: Near Real-time Monitoring of Biomass Burning Particulate Emissions (PM2.5) Using Multiple Satellite Data DESCRIPTION:Biomass burning is the second largest source of aerosols, which affects air quality and the Earth’s radiation budget. Because the emissions of aerosols is strongly influenced by factors including biomass density, combustion efficiency, and burned area, current burning emission estimates are rather imprecise and vary markedly with different methodologies. The aim of this study is to model biomass burning emissions using satellite-derived vegetative fuel loadings, fuel moisture, and fire sizes in the USA. For this purpose, we first developed an approach for mapping vegetative fuel loadings using Moderate-Resolution Imaging Spectroradiometer (MODIS) data at a spatial resolution of 1 km. MODIS data used in this study were land cover types, vegetation continuous fields, and a time series of leaf-area index (LAI). This dataset were compared with the fuel datasets derived from National Fire Danger Rating System (NFDRS) and Fuel Characteristic Classification System (FCCS). We then determined weekly fuel moisture categories from AVHRR-based vegetation condition index (VCI) to estimate fuel combustion efficiency and emission factors. The VCI was calculated by normalizing the NDVI (normalized difference vegetation index) to the difference of the extreme NDVI fluctuations (maximum and minimum) from 1982-2004. Further, we derived sub-pixel fire sizes from GOES WF_ABBA fire products at an interval of 30 minutes. We integrated all these parameters to produce aerosols (PM2.5, particulate mass for particles with diameter < 2.5 m) for each individual fire in 2002-2004 across the USA. Finally, we compared the daily estimates with National Wildfire Emissions Inventory data. The results suggest the biomass burning emissions from multiple satellite data can be applied to air quality forecast in near real time. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060307T110000 SUMMARY:Brian Vant-Hull and Yuan Tianle : A potluck of aerosol indirect effect, viewing geometry and retrieval biases from MODIS DESCRIPTION:The MODIS instrument offers the possibility of studying the aerosol indirect effect for small cumulus cloud fields with measurements of aerosol and cloud at approximately the same time and location. A distinctive relationship emerges when droplet effective radius increases with increased aerosol loading for clouds studied around the US Gulf coast, which is opposite to most past findings that show a 'Twomey-like' behavior. The contrast between the 3-dimensional nature of cumulus clouds and 1-dimensional retrieval algorithms is brought to the forefront. Influences of viewing geometry on the measurements and the impact on satellite studies of the aerosol indirect effect are examined.\n\nThe first part of the talk presents results from a study of the clouds from the US Gulf coast. It is demonstrated that aerosols may increase the droplet effective radius with an efficiency dependant upon the environmental water vapor.\n\nIn the second part of the talk it is shown that the observation of shallow clouds in Amazonia leads to coupled biases in the aerosol and effective radius retrievals. By varying the viewing geometry, either Twomey-like or Gulf-like behavior is observed. The common factor coupling the biases appears to be cloud geometry.\n\nThe last part of talk demonstrates that after carefully filtering the data to eliminate the effects of 3D geometry discussed in the second part, the anomalous relationship in the gulf region stands. An inter-comparison study using two methods shows a similar conclusion. These results raise the exciting possibility of a new physical effect of aerosols on cumulus clouds.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060314T110000 SUMMARY:Yoram Kaufman, Sasha Smirnov, Brent Holben: AERONET cloud screening using 2 different philosophies - implementations and implications DESCRIPTION:AERONET cloud screening: Two philosophies–\nimplementation and implications\n\nModerator: Brent Holben, presenters Sasha Smirnov and Yoram Kaufman\n\nThe successful use of AERONET optical depth and inversion products is contingent upon separating data that are cloud contaminated from those that are responding only to aerosols and known gases. To take maximum advantage of the diurnal range of AERONET measurements, screening should be based solely on the collected data and not from ancillary sources. Because aerosol optical depth (AOD) is acquired more frequently than sky radiance observations the screening technique has relied on the aerosol optical depth. Furthermore, the AOD being an extensive property is common to both clouds and aerosols, thus advantage was taken of the temporal data based on the general assumption that clouds vary more rapidly through time than aerosols. The resulting series of algorithms based on thresholds triplet variance, diurnal smoothness and minimum observations has been implemented for nearly a decade with good success (Smirnov et al., 2000). \n\nClearly aerosol loading can vary rapidly in time and clouds vary slowly, thus, on occasion, contaminated data are accepted into and pure aerosol data rejected from the quality assured AERONET database. With the acquisition of over two orders of magnitude more AERONET data and in more diverse conditions since the initial study, this seminar will present two new examinations of the problem. Alexander Smirnov will provide an analysis of the modified Smirnov et al. algorithm while Yoram Kaufman will focus on the difference in the spectral variation of aerosols. The new techniques will be compared for selected diverse data sets with the existing algorithm results. We anticipate a lively discussion of the constraints, applicability and implications of the new approaches for the AERONET database. The coin flip begins at 11 am, March 14, in Rm F225.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room H114 DTSTART;TZID=US/Eastern:20060317T020000 SUMMARY:Jim Coakley: Space-borne observations of the effects of aerosols on clouds DESCRIPTION:Aerosols represent one of the greatest sources of uncertainty in assessments of climate change caused by humans. Modeling studies that include the interaction of aerosols with cloud droplets render such assessments utterly uncertain. Estimates of the effects of aerosols on clouds based on correlations of space-borne observations of aerosol burdens and cloud properties are ambiguous. The correlations may be affected by a number of physical processes which could have little to do with aerosol-cloud interactions. In addition, clouds and aerosols respond to the thermodynamics of their environment, further complicating the determination of the effects of aerosols on clouds. Biases in the retrievals of cloud properties likewise enhance estimates of the aerosol indirect effect. Nonetheless, observations of the response of clouds to aerosols obtained from ship tracks off the west coast of the U.S. and from observations of summertime marine stratocumulus in the northeastern Atlantic polluted by plumes from Europe show clouds responding in ways predicted by large eddy simulation cloud models. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060321T110000 SUMMARY:NASA ROSES potential proposals discussion forum DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060411T110000 SUMMARY:Hermann Gerber: Entrainement in Trade Wind Cumuli DESCRIPTION:We have had for a long time a reasonable conceptual idea how cumulus (Cu) clouds\nevolve: latent heat from condensation drives the positive buoyancy, entrainment of dry air from\noutside the Cu dilutes the cloud and changes the droplet size spectrum, and coalescence and\ncollection of the drops leads to precipitation. It thus is surprising that we are still unable to\nquantify sufficiently with observations or modeling these basic physical processes. The recent RICO (Rain in Cumulus over the Ocean) study on Carribean trade wind cumuli was designed to\nmeet again this challenge. We report here on RICO data analysis dealing with numerous\naircraft passes through the Cu, passes which are used to estimate the clouds’ vertical evolution\nand to quantify the entrainment and mixing processes. We take advantage of unique incloud\nmicrophysical data collected with a resolution of 10cm, as well as data from other probes on the\nNCAR C-130 aircraft. We determine for the first time which of the oft-described\nentrainment/mixing processes, “homogeneous or inhomogenous”, dominates these Cu, the\nlength scale of the entrained parcels, the percentage of cloud-free voids within the Cu caused by entrainment, and the role played by the newly activated cloud drops in the entrained air.\nRecommendations are given for additional research on Cu. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F128 DTSTART;TZID=US/Eastern:20060418T110000 SUMMARY:Ying Chen: Atmospheric deposition of nutrients to the Gulf of Aqaba seawater: Fluxes and Ecological Effects DESCRIPTION:Atmospheric deposition of dissolved nutrient species (e.g. Fe, N and P) can have an important impact on the productivity and structure of an oligotrophic oceanic ecosystem. Seminar will present the studies of atmospheric inputs of soluble nutrients and their ecological effects on a desert-surrounded oligotrophic sea, the Gulf of Aqaba. The Gulf receives practically no river’s discharge and thus atmospheric deposition could be a major external source of nutrients to this system. Seminar will report the two-year data of soluble aerosol nutrients over the Gulf, the comparison results between pure-water and seawater extraction of aerosol nutrients, the dry deposition fluxes of soluble nutrients calculated using a particle deposition model, the contribution of atmospheric inputs to the dissolved nutrient concentrations in the water column and their support to the new production. These field measurements are very important for modeling the nutrient budgets and dynamics in this oligotrophic sea which may be representative of other present day dust-dominated oligotrophic systems and particularly may represent future conditions of increased aridity and dust fluxes. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060425T110000 SUMMARY:Gregory Leptoukh: Exploring Aerosol and other Atmospheric data online with Giovanni (MOVAS) DESCRIPTION:MOVAS is a Giovanni interface oriented towards the aerosol studies with MODIS and model data. It allows quick exploration and online analysis of atmospheric data. In MOVAS and other Giovanni instances, a variety of options has been prototyped for the future implementation: parameter intercomparison, anomalies, zonal and meridional cross-sections, vertical profiles visualization (MLS, HALOE, AIRS), OMI L2G --> custom L3, quick access to subsets of identified or related higher resolution products, etc. Utilization of Giovanni in several projects (Ocean Color Time Series, A-Train Data Depot, NEESPI Data Center, etc.) is outlined. Statistical issues related to spatial and temporal averaging are addressed. Giovanni usage for convenient multi-sensor data intercomparison and data fusion is discussed. Feedback on the current and suggestions on the future features are solicited. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060509T110000 SUMMARY:Peter Colarco: Comparison of the GEOS-4 GOCART Aerosol Optical Thickness to AERONET and MODIS DESCRIPTION:We have implemented a version of the GOCART aerosol module into the NASA GEOS-4 transport model and data assimilation system. We have run simulations spanning the model years 2000 through 2004 running the model in a replay mode, using assimilated meteorology from the GEOS Data Assimilation System. Here we compare the simulated aerosol optical thickness to measurements from AERONET and retrievals from MODIS for the year 2000. In particular, we consider the effects of model horizontal resolution on the simulated AOT, as well as considering different sources for biomass burning and seasalt aerosols. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060516T110000 SUMMARY:IPCC review discussion forum (Chapter 2) DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060523T110000 SUMMARY:John DeVore, A.T. Stair, R.A. McClatchey, A.J. LePage: "Introducing SAM (Sun and Aureole Measurement), a New, Ground-based Capability for Measuring Cloud Optical Properties". DESCRIPTION:Visidyne has developed a new, ground-based capability for the remote measurement of cloud and aerosol optical properties. Named SAM, for Sun and Aureole Measurement, this system makes precise measurements of the radiance profile of the solar disk and aureole. The radiance of the solar disk affords a definitive measure of the column optical depth when corrected for forward scattering. The aureole profile is a measure of the forward scattering properties of the particles in the column and can be used to correct the optical depth. The aureole profile can also be used to derive the size distribution of particles in the column. Measurements of the SAM imaging system complement those of sun scanning photometers (e.g., AERONET), in that SAM is ideally suited to investigate the larger particles found in water and especially cirriform clouds. We present examples of SAM measurements and comparisons with Monte Carlo radiative transfer calculations. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060530T110000 SUMMARY:IPCC review discussion forum (Chapter 7) DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060613T110000 SUMMARY:AEROCENTER: In Remebrance of Yoram Kaufman DESCRIPTION:As many of us know, AEROCENTER was created by Yoram Kaufman. His departure is a great loss to all of us in the global aerosol community in particular and in the earth science community at large.\n\n\nIt would be nice for the AEROCENTER Forum to pay tribute to him in our own small way. Therefore, we will dedicate our first session following his departure for a sort of AEROCENTER Memorial Service in honor of Yoram Kaufman.\n\n\nAs usual, it will be an informal discussion forum, where several people can:\n(1) share some of the wonderful memories of Yoram they remember (I am sure that many people have such things to share, but not everyone had the opportunity to share them during the main Memorial service last Sunday).\n(2) make suggestions on what they would like to see for the future of the AEROCENTER Forum.\n\n\non Jun 13, 2006, at 11:00 AM, in room F225, bldg 33\n\n\nThanks to Judd who was originally scheduled to give a talk on that date for giving it up and for suggesting this activity.\nThanks to Hongbin for forwarding messages to the group during the most difficult days last week, when I was uncoordinated.\n\n\nIt would be great if everyone who has ever been in an AEROCENTER meeting could attend this one.\n\n\nIf you would like to speak, there is no need to let me know beforehand, just let me know as soon as you arrive at the meeting. Please try to arrive early.\n\n\nWith best regards,\nCharles Ichoku. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060616T110000 SUMMARY:Kazuaki Kawamoto: Cloud remote sensing from satellites and the application for understanding aerosol indirect effects. DESCRIPTION:Relationships between anthropogenic aerosols and low-level water clouds were investigated to better understand the aerosol indirect effect over East Asia. Results from numerical simulations yielded the anthropogenic aerosol concentration Ma. Satellite-derived products yielded information on low-level water cloud properties (cloud optical depth t, effective particle radius re, vertically integrated cloud droplet number Nc). Comparisons of monthly means for aerosols and clouds showed that t increased and re decreased as Ma increased. Such tendencies were consistent with the Twomey effect, which describes how aerosols affect cloud properties. Nevertheless, comparisons of Ma with t in April and October would suggest the importance of dynamic effects on cloud formation and maintaining processes. Values of Nc that were calculated from t and re also increased as Ma increased. This result also agreed with the Twomey effect by indicating that additional aerosols generated more cloud droplets. A comparison of Ma with lower and middle clouds revealed similar tendencies to the previous case (i.e., total water cloud case), but differences in re (i.e., larger for middle and smaller for lower clouds) reflected the vertical profile of aerosol numbers. However, differences in t (i.e., thicker for middle and thinner for lower clouds) might have been influenced by the vertical extent. If time permits, other examples of aerosol indirect effects, cloud-precipitation relationships will be also described. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060620T110000 SUMMARY:Allen Chu, Lorraine Remer, Vanderlei Martins: Highlights from the MILAGRO and INTEX-B Campaigns DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room F225 DTSTART;TZID=US/Eastern:20060627T110000 SUMMARY:Alexander Sinyuk: Simultaneous retrieval of aerosol and surface properties from a combination of AERONET and satellite data DESCRIPTION:We present a method for simultaneously retrieving aerosol and surface parameters from ground based and satellite observations collocated in space and time. We show that a combination of down and up-looking observations provides sufficient measurement constraints for characterizing both aerosol and surface properties with minimal assumptions. In order to employ this concept in AERONET processing, the standard inverse algorithm (Dubovik and King, 2000) has been modified to retrieve surface reflectance in addition to aerosol parameters when co-incident satellite measurements are available.\nThe method was applied to observations of smoke and desert dust over the Mongu (Zambia) and Solar Village (Saudi Arabia) AERONET sites respectively. The AERONET data were complemented by available observations from the MISR, MODIS, and POLDER-2 satellite sensors. The retrieved bidirectional reflectance factor (BRF) and surface albedo comparison shows good agreement between results obtained using observations from different satellites.\nThe robustness of the method is tested by analyzing surface albedo time series retrieved during periods of high aerosol optical depth variability and low seasonal changes in surface reflectance. The analysis shows that the performance of retrieval algorithm is stable under different aerosol loadings. It is shown that much of the observed surface albedo temporal variability could be attributed mostly to the combined uncertainty in satellite radiometric calibration and aerosol vertical distribution for Mongu and to differences in satellite angular sampling on different days for Solar Village.\nThe sensitivity of surface retrievals to assumptions on aerosol vertical distribution and aerosol particle shape are analyzed. It is found that the maximum error in retrieved surface albedo at 0.44 µm is 0.035 for aerosol optical depth 0.85 at 0.44 µm. For aerosol optical depths lower than ~ 0.7 the error in retrieved surface albedo is less than 0.02. Analysis of particle shape assumptions on surface retrievals showed that aerosol particle non-sphericity significantly affects the angular shape of BRF, but not the surface albedo.\nFinally, the sensitivity of AERONET aerosol retrievals to uncertainty in assumed surface reflectance is analyzed by comparing aerosol retrievals obtained with different surface assumptions. It is found that the uncertainty in surface reflectance model employed in the version 1 AERONET operational algorithm is larger than was previously assumed in (Dubovik et al., 2000) and may have more significant effect on the retrieved aerosol properties than was documented in that work. In particular, larger errors were encountered for the real part of the refractive index (~0.05-0.07 increase) and maximum of the particle size distribution (~ 20% decrease) retrievals for the Mongu case, when the aerosol optical depth was relatively small (~ 0.4 at 0.44 µm). The retrieved single scattering albedo uncertainties were within the error bars (0.03) estimated in (Dubovik et al., 2000), with the exception of the 0.44 µm retrievals for the desert dust case when they increased by ~0.09 and 0.07 for low and high aerosol loadings respectively.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room H114 DTSTART;TZID=US/Eastern:20060821T110000 SUMMARY:Prof. Colin Price: Lightning and Climate: The Water Vapor Connection DESCRIPTION:Lightning activity in thunderstorms is closely related to the intensity of vertical updrafts in deep convective clouds that also transport large amounts of moisture into the upper troposphere. Small changes in the amount of upper tropospheric water vapor (UTWV) can have major implications for the Earth's climate. We present evidence showing a strong connection between the daily variability of tropical lightning activity and daily upper tropospheric water vapor concentrations. Our results over the African continent show that the upper tropospheric water vapor peaks one day after intense lightning activity in the tropics. Since regional and global lightning activity can be monitored from a few ground stations around the world via the electromagnetic phenomenon known as the Schumann resonances, we suggest the possible use of continuous lightning observations for studying the daily variability of upper tropospheric water vapor. \n\nPrice, C., and M. Asfur, 2006: Can lightning observations be used as an indicator of upper-tropospheric water vapor variability? Bull. Amer. Meteor. Soc., 87, 291–298.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 F225 DTSTART;TZID=US/Eastern:20060829T110000 SUMMARY:Nicholas Meskhidze: The effect of phytoplankton on clouds in the Southern Ocean: A natural “shiptrack” (or “smog chamber”?) DESCRIPTION:The effect of ocean biological productivity on marine clouds is explored over the large phytoplankton bloom in the Southern Ocean using remotely sensed data. Compared to the background, cloud droplet number concentration over the bloom was doubled and cloud effective radius was reduced by 30%. The resulting change in the short-wave radiative flux at the top-of-the-atmosphere is -15W m^ -2, comparable to the aerosol indirect effect over highly polluted regions. This is by far the strongest impact of phytoplankton on clouds observed to date, and is attributed to changes in the size-distribution and chemical-composition of cloud condensation nuclei (CCN). We propose that secondary organic aerosol (SOA) formed from the oxidation of phytoplankton-produced isoprene, may strongly affect chemical composition of marine CCN and impact cloud droplet number. Model simulations support this hypothesis, as 100% of the observed changes in cloud properties can be attributed to the isoprene SOA. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20060912T110000 SUMMARY:Lorraine Remer: Looking forward: Where the "MODIS aerosol group" goes from here DESCRIPTION:We are at a turning point. Yoram is gone. We are at the end of a 3 year funding cycle. The Collection 005 reprocessing is cranking out a much superior product than was available previously. A natural question arises, "Are we done?"\n\nThe only thing I can say is, "If we are done, why am I still working so hard?"\n\nWe are far from done. In this talk I will describe the work we are doing that will take us through the next 3 year funding cycle and beyond. This will include:\n- plans for the MODIS algorithm\n- topics in aerosol-cloud interaction\n- topics in aerosol absorption and aerosol composition\n- topics in air quality and long range transport of pollutants\n- a look at lidar\n- ideas for future satellite missions\n\nThis will be a very informal presentation with lots of ideas and not that many results.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20060919T110000 SUMMARY:Paper Discussion : Kaufman, Y. J., and I. Koren, 2006: Smoke and Pollution Aerosol Effect on Cloud Cover. SCIENCE, 313, 655-658, doi: 10.1126/science.1126232 DESCRIPTION:Pollution and smoke aerosols can increase or decrease the cloud cover. This duality in the effects of aerosols forms one of the largest uncertainties in climate research. Using solar measurements from Aerosol Robotic Network sites around the globe, we show an increase in cloud cover with an increase in the aerosol column concentration and an inverse dependence on the aerosol absorption of sunlight. The emerging rule appears to be independent of geographical location or aerosol type, thus increasing our confidence in the understanding of these aerosol effects on the clouds and climate. Preliminary estimates suggest an increase of 5% in cloud cover. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20060926T110000 SUMMARY:Francis Okeke: Satellite monitoring of environmental change: the Nigerian experience DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20061003T110000 SUMMARY:Saulo Freitas DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20061010T110000 SUMMARY:Mike Fromm: 'Particle'larly Interesting Science: The Meaning, Marvels, and Mysteries of PyroCumulonimbus DESCRIPTION:Pyroconvection is not a new concept. However, the idea that pyroconvection can be explosive enough to inject into the stratosphere a smoke plume that pollutes hemispherically, goes against the grain of textbook atmospheric physics. Since the discovery of forest fire smoke in the stratosphere, skepticism has given way to acceptance, understanding, excitement, and wonder. That is because pyrocumulonimbus (pyroCb for short) research continues to make more discoveries, involve growing collaborations, and invite new questions.\n\nThis talk will give an overview of pyroCb research. It will focus on observations, from satellite, ground, and aircraft. Satellite-based emphasis will be on platforms such as MODIS, TOMS, OMI, MISR, AVHRR, GOES, DMSP, SAGE, POAM, HALOE. Revelations from groundbased resources such as AERONET and lidar will also be exploited. Finally, some ideas on how to study pyroCb with the A-Train will also be presented.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20061024T110000 SUMMARY:Pete Colarco: Future Satellite Measurements of Aerosols: What do models need to know? DESCRIPTION:As NASA's EOS sensors age and the A-Train constellation is filled in, it is important to think what future NASA satellite missions are needed to increase our understanding of the role of aerosols in Earth's climate system. Here we pose the question of what missions are needed in the context of what modelers of the global aerosol system need to know to improve their models, and hence their estimates of the impact of aerosols on Earth' climate. For example, recent reviews and model intercomparisons suggest that while models may generally converge toward a particular value for the global aerosol optical thickness, there is a wide diversity in the contribution of particular species (e.g., dust, black carbon, etc.) to that total in the various models. This illustrates a need for more information about the composition of aerosols. We review other such examples and suggest measurements needed to address these questions. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20061031T110000 SUMMARY:Paper Discussion DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20061107T110000 SUMMARY:Tad Anderson: 'Stay the Course' or 'Cut and Run'? Strategic Considerations Regarding the Quantification of Climate Forcing by Anthropogenic Aerosols DESCRIPTION:Since the second year of the Ford Administration when Junge outlined the problem, atmospheric scientists have been engaged in a mission to beat down the uncertainties in Aerosol Climate Forcing. The intervening years have seen exponential increases in the number of scientist attacking this problem, the power of their instrumental and computational weaponry, and, of course, the overall cost of the mission. Publications have also increased exponentially, and yet, five Presidents and four party switches later, any semblance of victory remains elusive. Even our weakest enemy (the "direct forcing" problem), though targeted in well-armed field campaigns, has managed to stage repeated comebacks via such unanticipated tactics as the insertion of absorbing aerosol above boundary layer clouds, where its effects may be great and yet are almost impossible to measure. Meanwhile, the hydra-headed monster known as "indirect forcing", while surrendering tiny slivers of territory, has only grown in overall strength and incomprehensibility. Our great nation stands this very day at a turning point - a moment of decision. Shall we battle on with our bottom-up techniques, as the mad-dogs of the Red Party advocate? Shall we abandon the field to top-down (or inverse) methods, wherein we merely pick the forcing value that allows a climate model to fit the temperature record, as called for by the cowards of the Blue Party? Should we listen to those queer Third Party voices, urging, for example, approaches based on monitoring the heat content of the ocean or the albedo of the entire planet? These are trying and confusing times, and yet the choice is upon us. My goal in this presentation and the discussion to follow is not to recommend any particular course of action, but to help equip us to choose wisely. Specific topics will include: What do recent, so- called "observation-based" estimates of direct forcing tell us about the state of the science? What do we know about the accuracy of AERONET retrievals of absorption optical depth and fine-mode fraction? How does the notion of an aerosol/cloud continuum affect our observational and modeling strategies? Even though they cannot vote today, non-U.S. citizens are encouraged to come and participate - we need all the help we can get! END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room F225 DTSTART;TZID=US/Eastern:20061114T110000 SUMMARY:Alexei Lyapustin and Yujie Wang : A new generic aerosol retrieval-atmospheric correction algorithm for MODIS DESCRIPTION:If given a consecutive set of images of the same region of the Earth obtained from space, an untrained human will easily solve many of the remote sensing problems, such as selecting clear-skies areas, identifying clouds, distinguishing between clear and hazy conditions, and so on. What, in contrast to our brain’s work, is missing in our algorithms, armed with the modern science, that solving these problems becomes difficult and fraught with uncertainties?\nOne answer is that the contemporary concepts of aerosol and land surface remote sensing from whiskbroom (MODIS-like) sensors are pixel-based and disregard history of previous measurements. In this case, some important invariants of the atmosphere-surface system are overlooked. One example is a spatial structure (or texture) of the land surface at the landscape level, which generally changes at a very slow rate as compared to the frequency of spaceborne observations.\nIn this seminar, I will describe a new MODIS land algorithm, which uses multi-temporal observations and an image-based rather than pixel-based processing. The new algorithm retrieves aerosol optical thickness simultaneously with surface bidirectional reflectance and albedo. It is generic and works over the dark vegetated and bright non-vegetated world regions with the current exception of snow-covered areas. The algorithm has internal water vapor retrievals and a new cloud mask algorithm. An initial validation shows an excellent agreement of our retrievals with AERONET water vapor and aerosol measurements.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20061121T110000 SUMMARY:Jun Wang, Andrew H. Hoffman, Scot T. Martin, and Daniel J. Jacob: Sensitivity of sulfate aerosol direct climate forcing to the particle physical state: A global perspective DESCRIPTION:Accurate estimate of sulfate aerosol direct climate forcing (DCF) requires spatial and temporal characterization of DCF dependence on the crystalline and aqueous states of sulfate particles. This characterization is practically difficult for both passive remote sensing and chemistry transport models (CTMs), because sulfate phase transition is hysteretic in nature and their optical properties varies with relative humidity history as well as chemical composition of the particle. To date, our knowledge of sulfate physical state in the ambient air is rather limited, especially from a global perspective. \n\nIn this presentation, I will first introduce our recent efforts in using a 3D global chemistry transport model (Harvard’s GEOS-CHEM) to explicitly simulate the distribution of aqueous sulfate particles and crystalline ammonium sulfate, letovicite, and ammonium bisulfate particles. Based upon our model results, the DCF uncertainty metrics are analyzed in context of various previous studies that assumed different sulfate physical state for the calculation of optical properties. In the end, the implication of this study for the investigation of cirrus cloud formation as well as the potential of active remote sensing for the retrieval of aerosol phase transition will also be discussed.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20061128T110000 SUMMARY:Paper Discussion DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION: DTSTART;TZID=US/Eastern:20061212T090000 SUMMARY:Fall AGU DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20061219T110000 SUMMARY:Eric Shettle: Potential of Nighttime Aerosol Retrievals with VIIRS DESCRIPTION:Previous satellite measurements of the atmospheric aerosol optical depth (AOD) have utilized measurements of backscattered sunlight, starting with the AVHRR [Advanced Very High Resolution Radiometer] measurements on the NOAA polar-orbiting satellites and including NASA's MODIS instruments on the Terra and Aqua Satellites. The National Polar-orbiting Operational Environmental Satellite System [NPOESS], which is currently being developed for the next generation of polar-orbiting meteorological measurements, will also use backscattered solar radiation with the Visible Infrared Imaging Radiometer Suite [VIIRS] to measure the AOD. The NPOESS AODs will cover a much wider spectral range and an improved aerosol size characterization than NOAA's current operational aerosol products from AVHRR, building on the experience with the MODIS instruments. In addition the VIIRS instrument also includes a Daytime/Nighttime Visible Imagery band or the Day-Night Band (DNB) which is a broad band channel covering from about 500 to 900 nm, with sufficient dynamic range to provide calibrated cloud imagery from quarter moon to full sunlight. This presentation will discuss the potential of using backscattered moonlight from the DNB to provide an additional new capability of nighttime measurements of AOD. We have used MODTRAN to simulate the lunar radiances scattered by the atmosphere under different conditions and investigate the possibility of using the DNB to provide nighttime measurements of AOD. Our simulations indicate that uncertainties in the retrieved AODs at night will be largely determined by accuracy of the DNB calibration near the lower limits of its operating range. Assuming a radiometric calibration accuracy of about 10% could be achieved, there would be sufficient signal-to-noise to measure the AOD with an uncertainty of ±0.08 to ±0.09 for lunar phase angle of 60° near nadir. The uncertainty increases towards the edge of the across-track scan. While this is far short of the day-time capabilities of VIIRS, it is sufficient to provide quantitative information on regions of high aerosol loading. This would provide improved temporal information on the transport of desert dust or other transient phenomena (such as Land/Sea breeze), due to the addition of nighttime measurements to supplement the daytime data. The presence of the aurora could mask any aerosol signal. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Lobby DTSTART;TZID=US/Eastern:20070109T110000 SUMMARY:AEROCENTER Annual Poster Session DESCRIPTION:Important posters from different (especially recent) meetings that took place in 2006 are welcome. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room F225 DTSTART;TZID=US/Eastern:20070123T110000 SUMMARY:Zhanqing Li: Validation of the MODIS Aerosol Products over China DESCRIPTION:The MODIS aerosol products have been widely used for addressing global climatic issues, but no validation has been done over the vast territory of China. Thanks to the EAST-AIRE project, extensive aerosol measurements have been taken since 2004 using both Cimel and hand-held sunphotometers across China. In comparison with ground observations, the newly revised aerosol retrieval algorithm (C005) showed much better performance than previous ones, but further improvements are needed to better tackle the effects of surface reflectance and aerosol type. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room F225 DTSTART;TZID=US/Eastern:20070130T110000 SUMMARY:Nikisa S. Jordan: Estimating Smoke Emissions Over the U.S Southern Great Plains Using MODIS Fire Radiative Power(FRP) Measurements DESCRIPTION:Two general methods exist to estimate emissions from fires: (1) an indirect method combining satellite measures with an emissions-factor model and (2) a direct method that involves the use of measurements of energy released by a fire. The indirect approach (1) has been widely used but limitations and uncertainties exist. Direct correlations have recently been published which show the statistically significant relationship between biomass combusted and Fire Radiative Energy (FRE). Moreover, the direct approach (2) relies less on external parameters and has been used with the intent to adequately minimize uncertainties evident in the indirect approach. Coarse global scale analysis has been done using the technique but no fine scale analysis has been presented for the U.S. Southern Great Plains, which is the area of interest in this study. This region was chosen since extensive burning occurs annually. The primary focus of this research was to employ the direct method to obtain smoke emission rates for the selected area. More specifically, the objective was to derive the FRE-based coefficient of smoke emission (Ce) for the U.S. Southern Great Plains using MODIS FRE rates and Aerosol Optical Depth (AOD) data. The Ce derived was comparable to results published by Ichoku and Kaufman (2005) for smoke emission estimation of similar fuel types.\n\nIchoku, C. and Kaufman, Y.J., (2005), A method to derive smoke emission rates from MODIS fire radiative energy measurements, IEEE Transacations on Geosceince and Remote Sensing, 43, 11, 2636-2649.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20070213T110000 SUMMARY:Raymond Rogers: Daytime Raman Lidar Measurements of Hygroscopic Growth DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room F225 DTSTART;TZID=US/Eastern:20070306T110000 SUMMARY:Paper Discussion : Hu, R.-M., R.V. Martin, and T.D. Fairlie, Global retrieval of columnar aerosol single scattering albedo from space-based observations, J. Geophys. Res., in press, 2007 DESCRIPTION:We retrieve the global distribution of columnar single scattering albedo (SSA) by\ntaking advantage of the high sensitivity of satellite measurements at ultraviolet channels by the Total\nOzone Mapping Spectrometer (TOMS) to both aerosol optical depth and SSA, and the high sensitivity\nof satellite measurements at visible channels by the Moderate Resolution Imaging SpectroRadiometer\n(MODIS) to aerosol optical depth. A radiative transfer model (LIDORT) is used to calculate the local SSA that reproduces the TOMS aerosol index, when constrained by MODIS aerosol optical depth and by\nrelative vertical profiles from a global chemical transport model (GEOS-CHEM). The simulated aerosol\npro les are evaluated with lidar measurements of aerosol extinction. The retrieved !0 at 360 nm is\nnear 1 over the remote ocean, in contrast with values of 0.75 to 0.9 over regions dominated by biomass\nburning and mineral dust aerosol. The retrieval uncertainty is 15 percent. We validate our retrieval\nwith measurements from the Aerosol Robotic Network (AERONET); the correlation coecient, slope\nand intercept are 0.75, 0.99 and 0.02 respectively. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20070313T110000 SUMMARY:Nicole Riemer: Variability of African dust transport across the Atlantic DESCRIPTION:The North African continent represents a dominant global source of mineral dust. It has\nbeen known for a long time that that large dust plumes are transported to the Atlantic\nOcean and the Mediterranean Sea from the Saharan desert and surrounding regions. This\nexport is subject to a strong interannual variability, which in turn is related to the largescale\ncirculation. Understanding this variability is key to quantifying the impact of\nmineral dust on the various processes in the climate system.\nWe will present a new approach for analyzing the seasonal and interannual variability of\nSaharan Dust transport over the Atlantic using TOMS/NIMBUS-7 and TOMS/Earth\nProbe satellite aerosol data and the atmospheric “Centers of Action”.\nWe focus our analysis on two examples: Firstly, we investigate the area off the North-\nWest African coast (15-30oN, 30-5oW) during the winter season. Previous studies have\nsuggested that the variability of the Saharan dust in this region can be partially explained\nby the North Atlantic Oscillation. We show that this picture can be improved upon by\napplying the Centers of Action approach, which decouples the semi-permanent pressure\nsystems in the Atlantic, the Azores High and the Icelandic Low.\nThe second example focuses on the transport of Saharan mineral dust to the Carribean.\nAn increasing trend in the quantity of mineral dust over the Caribbean is observed during\nthe 1980s with elevated dust levels being present into the 21st century. Furthermore, the\nyearly duration of the time in which dust is present in the Caribbean has been drastically\nincreasing. We show that both increased emissions and changes in transport patterns\ncontribute to the observed trend. We apply the Centers of Action approach to gain insight\ninto the atmospheric controls on Saharan Dust into the Caribbean and identify the\nlongitudinal displacement and the pressure of the Hawaiian High and the longitudinal\ndisplacement of the Azores High as key players. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room F225 DTSTART;TZID=US/Eastern:20070327T110000 SUMMARY:Zahra Chaudhry : In Situ Measurements of Aerosol Mass Concentration and Radiative Properties in Xianghe, SE of Beijing DESCRIPTION:As a part of the EAST-AIRE study, Nuclepore filters were collected in two size ranges (coarse, 2.5µm < d < 10µm, and fine, d < 2.5µm) from January-May 2005 in Xianghe, about 70 km southeast of Beijing and analyzed for aerosol mass concentration, spectral absorption efficiency and absorption coefficient. Twelve-hour aerosol mass concentration measurements showed an average concentration of 120 µg/m3 in the coarse mode, and an average concentration of 25 µg/m3 in the fine mode. To determine how representative ground-based measurements are of the total column, the mass concentration data was compared with AERONET AOT at 500nm and AERONET size distribution data. The vertical distribution of the aerosols were studied with a micro-pulse lidar and in the cases where the vertical column was found to be fairly homogenous, the comparisons of the filter results with AERONET agreed favorably, while in the cases of inhomogeneity, the comparisons have larger disagreement. For fine mode aerosols, the spectral absorption efficiency compares favorably to a (lambda-1) model, while the coarse mode shows a much flatter spectral dependence, consistent with large particle models. The coarse mode absorption efficiency was compatible with that of the fine mode in the NIR region, indicating the much stronger absorption of the coarse mode due to its composition and sizable mass. Single scattering albedo results are presented from a combination between absorption coefficients derived from the filter measurements, from a PSAP and from a three-wavelength Nephelometer. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room F225 DTSTART;TZID=US/Eastern:20070410T110000 SUMMARY:Brent Holben: Uncle AERONET needs you! DESCRIPTION:AERONET is nearly a decade and a half old, long enough to track significant evolutionary processes through algorithm development, aerosol products, site distribution, quality control, synergism with satellite, models and other data sets and various research applications not envisioned in 1992. This talk will discuss the migration of Version 1.0 aerosol products to Version 2.0 (try to convince you that V2 is better), vote on the continuance of V1 products and outstanding issues new to V2, and discuss some of the new evolutionary lines of mother AERONET. Please come, listen, participate and cast your vote before HS grinds the center to a halt. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room G133 DTSTART;TZID=US/Eastern:20070424T110000 SUMMARY:Tobias Zinner: Remote sensing of cloud sides of deep convective clouds : Simulating CLAIM-3D for realistic cloud situations DESCRIPTION:The CLAIM-3D (cloud aerosol interaction mission in 3-D) passive cloud side viewing sensor concept is planned to become a new means of measuring the vertical profile of cloud microphysical properties (particle size, phase, temperature) from airborne or satellite platforms. On the basis of simplified statistical cloud cases Marshak et al (2006) have proven the concept and introduced the idea of a Bayesian retrieval algorithm. Martins et al (2007) showed promising results for a first airborne case study. The question answered in this talk is, if the concepts work for realistic deep convection scenes with a complex mixture of water, ice and mixed phase cloud structures. It is shown that a Bayesian retrieval accounting for the 3D complexity of realistic cloud fields can be established based on a number of cloud data sets from the cloud resolving Goddard Cumulus Ensemble Model and consecutive 3D Monte Carlo simulations of the sensor observations. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room G133 DTSTART;TZID=US/Eastern:20070515T153000 SUMMARY:Rangasayi Halthore: Whatever happened to the shortwave ‘excess’ or the ‘anomalous’ absorption problem? DESCRIPTION:In the mid-90s a series of papers appeared reporting that the measured shortwave absorptance in cloudy and in some cases cloud-free atmospheres was much higher than model calculations. If true, this would have had serious consequences for climate studies and remote sensing. To a large extent these problems have been resolved by using improved calibration of instruments on board satellites, aircraft and at the surface. I will describe our efforts at resolving this problem concentrating mainly on cloud-free atmospheres. These efforts included a model intercomparison exercise, several diffuse flux measurement intercomparison efforts and an understanding of the role of aerosol properties, in particular, its absorption. I will describe these and other related issues in an attempt at resolving the remaining problems. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room G133 DTSTART;TZID=US/Eastern:20070529T153000 SUMMARY:Wei Kuo Tao: The role of atmospheric aerosol concentration on deep convective precipitation: Cloud-resolving model simulations DESCRIPTION:A two-dimensional cloud-resolving model (CRM) with detailed spectral-bin microphysics is used to examine the effect of aerosols on three different deep convective cloud systems that developed in different geographic locations: South Florida, Oklahoma and the Central Pacific. A pair of model simulations, one with an idealized low CCN (clean) and one with an idealized high CCN (dirty environment), is conducted for each case.\n\nIn all three cases, rain reaches the ground earlier for the low CCN case. Rain suppression is also evident in all three cases with high CCN. However, this suppression only occurs during the first hour of the simulations. During the mature stages of the simulations, the effects of increasing aerosol concentration range from rain suppression in the Oklahoma case, to almost no effect in the Florida case, to rain enhancement in the Pacific case. The model results suggest that evaporative cooling is a key process in determining whether high CCN reduces or enhances precipitation. Stronger evaporative cooling can produce a stronger cold pool and thus stronger low-level convergence through interactions with the low-level wind shear. Consequently, precipitation processes can be more vigorous. For example, the evaporative cooling is more than two times stronger in the lower troposphere with high CCN for the Pacific case. Sensitivity tests also suggest that ice processes are crucial for suppressing precipitation in the Oklahoma case with high CCN. A brief comparison and review of other modeling studies are also presented.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room G133 DTSTART;TZID=US/Eastern:20070605T110000 SUMMARY:Paper Discussion : Dimming Effect: Mishchenko et al.(2007) Science, Streets et al. (2006) GRL, Wild et al. (2007) GRL DESCRIPTION:Long-Term Satellite Record Reveals Likely Recent Aerosol Trend\nMichael I. Mishchenko,* Igor V. Geogdzhayev, William B. Rossow, Brian Cairns, Barbara E. Carlson, Andrew A. Lacis, Li Liu, Larry D. Travis\nScience 16 March 2007: Vol. 315. no. 5818, p. 1543, DOI: 10.1126/science.1136709\nAbstract: Analysis of the long-term Global Aerosol Climatology Project data set reveals a likely decrease of the global optical thickness of tropospheric aerosols by as much as 0.03 during the period from 1991 to 2005. This recent trend mirrors the concurrent global increase in solar radiation fluxes at Earth's surface and may have contributed to recent changes in surface climate.\nhttp://www.sciencemag.org/cgi/content/summary/sci;315/5818/1480\n\n\nGEOPHYSICAL RESEARCH LETTERS, VOL. 33, L15806, doi:10.1029/2006GL026471, 2006\nTwo-decadal aerosol trends as a likely explanation of the global dimming/brightening transition\nDavid G. Streets , Argonne National Laboratory, Argonne, Illinois, USA\nYe Wu Energy Systems Division, Argonne National Laboratory, Argonne, Illinois, USA\nMian Chin NASA Goddard Space Flight Center, Greenbelt, Maryland, USA\nhttp://www.agu.org/pubs/crossref/2006/2006GL026471.shtml\nAbstract: Global average trends in solar radiation reaching the Earth's surface show a transition from dimming to brightening that occurred in about 1990. We show that the inter-annual trend in solar radiation between 1980 and 2000 mirrors the trend in primary emissions of SO2 and black carbon, which together contribute about one-third of global average aerosol optical depth. Combined global emissions of these two species peaked in 1988 - 1989. The two-decadal rate of decline in aerosol loading resulting from these emission changes, 0.13% yr(-1), can be compared with the reported increase in solar radiation of 0.10% yr(-1) in 1983 - 2001. Regional patterns of aerosol and radiation changes are also qualitatively consistent. We conclude that changes in the aerosol burden due to changing patterns of anthropogenic emissions are likely contributing to the trends in surface solar radiation.\n\n\nGEOPHYSICAL RESEARCH LETTERS, VOL. 34, L04702, doi:10.1029/2006GL028031, 2007\nImpact of global dimming and brightening on global warming\nhttp://www.agu.org/pubs/crossref/2007/2006GL028031.shtml\nMartin Wild Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland\nAtsumu Ohmura Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland\nKnut Makowski Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland\nAbstract\nSpeculations on the impact of variations in surface solar radiation on global warming range from concerns that solar dimming has largely masked the full magnitude of greenhouse warming, to claims that the recent reversal from solar dimming to brightening rather than the greenhouse effect was responsible for the observed warming. To disentangle surface solar and greenhouse influences on global warming, trends in diurnal temperature range are analyzed. They suggest that solar dimming was effective in masking greenhouse warming, but only up to the 1980s, when dimming gradually transformed into brightening. Since then, the uncovered greenhouse effect has revealed its full dimension, as manifested in a rapid temperature rise (+0.38°C/decade over land since mid-1980s). Recent solar brightening cannot supersede the greenhouse effect as main cause of global warming, since land temperatures increased by 0.8°C from 1960 to 2000, even though solar brightening did not fully outweigh solar dimming within this period.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room G133 DTSTART;TZID=US/Eastern:20070612T110000 SUMMARY:Yogesh Sud, Dongmin Lee, and G. K. Walker: Parameterization of aerosol indirect effects (AIE) to complement McRAS and its evaluation with the ARM-SGP SCM data and GCM simulations DESCRIPTION:"Microphysics of clouds with the Relaxed Arakawa¬Schubert Scheme (McRAS)" was used for several recent cloud microphysics-climate interaction studies with GEOS4 GCM. Its Sundqvist cloud microphysics algorithms however ignore aerosol-cloud interaction, the topic of primary interest to the aerosol scientists in the group. The aerosol direct effect was relatively easy to include, once aerosol optical properties, mass fraction and size distribution fields are known a priori, such as provided by the GOCART model runs, the aerosol indirect effect is more difficult; it invokes aerosol activation, cloud droplet growth, precipitation microphysics, and the most challenging of all, algorithms for phase change processes between ice and water clouds and their optical properties. To accommodate these needs, McRAS was upgraded to include the Aerosol Indirect Effects (AIE) comprising of: (i) Fountoukis and Nenes (2005) aerosol activation module for obtaining cloud condensation nuclei; (ii) Seifert and Beheng (2006) algorithms for precipitation microphysics, except for modified accretion constant for the coarse vertical-resolution typical of a global general circulation model (GCM); (iii) Liu and Penner ice-cloud microphysics (recently included in the package); and (iv) Khvorostyanov and Curry parameterization for the effective radius (re) of cloud drops.\n\nThe rationales for choosing these algorithms and preliminary results of simulations made with Single Column Model and GEOS4 GCM will be presented. Overall, the upgraded package simulates quite realistic annual cycles of cloud water, cloud optical thickness, CDNC, and re. The impact of aerosol mass concentration on the column cloud water, and bulk optical properties of clouds were also assessed by varying the aerosol mass concentration.\n\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room G133 DTSTART;TZID=US/Eastern:20070619T110000 SUMMARY:Eric Wilcox: Towards empirical and model estimates of aerosol indirect forcing DESCRIPTION:I will present the results of an effort to estimate the magnitude of top-of-atmosphere radiative forcing attributable to aerosol-cloud interactions using a blending of in-situ and satellite observations, as well as using satellite observations alone. Empirical strategies using satellite data are subject to some significant limitations and uncertainties which are now familiar to most of us. Thus we also rely on numerical models to estimate the forcing and the climate response to it. However, the empirical results derived from observations of cloud microphysics and radiative forcing also lend themselves to the statistical validation of new GCM parameterizations of aerosol-cloud interactions, such as the one presented by Dr. Yogesh Sud in the previous Aerocenter presentation, which predicts the concentration and size of cloud drops in response to variations in the aerosol concentration. I will present some results of this validation effort and some early results from simulations with this new GCM. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room G133 DTSTART;TZID=US/Eastern:20070626T110000 SUMMARY:Paper Discussion : Aerosol Effects: Ackerman etal (2004) Nature, Hegg et al. (2007) TELLUS DESCRIPTION:Indirect Effect: Factors that modulate cloud albedo.\n\nThe impact of humidity above stratiform clouds on indirect aerosol climate forcing\nhttp://www.nature.com/nature/journal/v432/n7020/full/nature03174.html\nAndrew S. Ackerman1, Michael P. Kirkpatrick2, David E. Stevens3 and Owen B. Toon4\n 1. NASA Ames Research Center, Moffett Field, California 94035, USA\n 2. University of Tasmania, Hobart, TAS 7001, Australia\n 3. Lawrence Livermore National Laboratory, Livermore, California 94552, USA\n 4. University of Colorado, Boulder, Colorado 80309, USA\nCorrespondence to: Andrew S. Ackerman1 Email: andrew.ackerman@nasa.gov\nAbstract\nSome of the global warming from anthropogenic greenhouse gases is offset by increased reflection of solar radiation by clouds with smaller droplets that form in air polluted with aerosol particles that serve as cloud condensation nuclei1. The resulting cooling tendency, termed the indirect aerosol forcing, is thought to be comparable in magnitude to the forcing by anthropogenic CO2, but it is difficult to estimate because the physical processes that determine global aerosol and cloud populations are poorly understood2. Smaller cloud droplets not only reflect sunlight more effectively, but also inhibit precipitation, which is expected to result in increased cloud water3, 4. Such an increase in cloud water would result in even more reflective clouds, further increasing the indirect forcing. Marine boundary-layer clouds polluted by aerosol particles, however, are not generally observed to hold more water5, 6, 7. Here we simulate stratocumulus clouds with a fluid dynamics model that includes detailed treatments of cloud microphysics and radiative transfer. Our simulations show that the response of cloud water to suppression of precipitation from increased droplet concentrations is determined by a competition between moistening from decreased surface precipitation and drying from increased entrainment of overlying air. Only when the overlying air is humid or droplet concentrations are very low does sufficient precipitation reach the surface to allow cloud water to increase with droplet concentrations. Otherwise, the response of cloud water to aerosol-induced suppression of precipitation is dominated by enhanced entrainment of overlying dry air. In this scenario, cloud water is reduced as droplet concentrations increase, which diminishes the indirect climate forcing.\n\nTellus B Volume 59 Issue 1 Page 66 - February 2007\nD. A. HEGG, K. NIELSEN, D. S. COVERT, H. H. JONSSON, P. A. DURKEE (2007)\nFactors influencing the mesoscale variations in marine stratocumulus albedo\nTellus B 59 (1), 6676.\ndoi:10.1111/j.1600-0889.2006.00231.x \nMeasurements of both horizontal gradients and vertical profiles of aerosols, cloud droplets and thermodynamic parameters in the cloud topped marine boundary layer off of central California are presented. They suggest that, while aerosols can indeed modulate cloud albedo, other parameters such as sea surface temperature may similarly affect cloud albedo. Additionally, the impact of aerosols, through sedimentation and precipitation, on cloud optical depths and thus albedo is not always in accord with conventional expectations and can either enhance or decrease the albedo, depending on ambient conditions. Taken together, these results suggest that current estimates of indirect forcing by aerosols could be significantly in error.\n\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room G133 DTSTART;TZID=US/Eastern:20070703T110000 SUMMARY:Ariel Stein: TBA DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room E125 DTSTART;TZID=US/Eastern:20070809T110000 SUMMARY:Norm O'Neill: Recent developments in UV to SWIR* spectrometry from AERONET data DESCRIPTION:The spectral deconvolution algorithm (SDA) whose output of fine and coarse mode optical depth is currently an AERONET product is reviewed with respect to recent findings which include an empirical demonstration of the rather subtle difference between FMF and SMF (fine mode fraction and sub- micron mode fraction). An extended spectral deconvolution algorithm (SDA+) which exploits the added information content of the new 1.64 um AERONET band will be discussed along with results from the recent UAE^2 experiment. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33 Room G133 DTSTART;TZID=US/Eastern:20070814T110000 SUMMARY:Jonathan Jiang: Connecting surface emissions, convective uplifting, and long-range transport of carbon monoxide in the upper-troposphere: New observations from the Aura MLS and other "A-Train" satellites DESCRIPTION:Two years of observations of upper tropospheric (UT) carbon monoxide (CO) from the Aura Microwave Limb Sounder are analyzed in combination with the CO surface emission climatology and data from other A-Train satellites and chemical transport models. It is shown that spatial distribution, temporal variation and long-range transport of UT CO are closely related to the surface emissions, deep-convection and horizontal winds. Over the Asian monsoon region, surface emission of CO peaks in boreal spring due to high biomass burning in addition to anthropogenic emission. However, the UT CO peaks in summer when convection is strongest and surface emission of CO is dominated by anthropogenic source. The long-range transport of CO from Southeast Asia across the Pacific to North America, which occurs most frequently during boreal summer, is thus a clear imprint of Asian anthropogenic pollution influencing global air quality. Comparisons of these satellite observations against two global three-dimensional global air quality models (GEM-AQ and GEOS-CHEM) reveal significant differences, which indicate models may have difficulty representing transport by deep convection in the UT. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room G133 DTSTART;TZID=US/Eastern:20070828T110000 SUMMARY:Easan Evans Drury: Using locally inferred surface reflectance ratios and aerosol optical properties from a chemical transport model (CTM) to retrieve aerosol optical depths (AODs) from MODIS reflectances over land. DESCRIPTION:Quantitative evaluation of aerosol fields from chemical transport models (CTMs) with aerosol optical depth (AOD) products retrieved from satellite backscattered reflectances can be compromised by inconsistent assumptions of aerosol optical properties and errors in surface reflectance estimates. We have developed a method for estimating local (1x1.25 degree) 0.65 ?m /2.13 ?m surface reflectance ratios from MODIS top of the atmosphere (TOA) reflectances under conditions where we expect minimal aerosol reflectance. Using this estimate of surface reflectance and aerosol optical properties from the global CTM GEOS-Chem, we model TOA reflectances for each MODIS scene in the sun / satellite geometry of the instrument. We use the modeled to MODIS reflectance comparison to iteratively scale modeled AODs. Comparison of AODs retrieved using this method with collocated AERONET AODs and collection 4 and 5 MODIS AODs will be discussed. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room G133 DTSTART;TZID=US/Eastern:20070918T110000 SUMMARY:Brent Holben: Herding CATZ DESCRIPTION:Throughout the course of human history, seemingly random chaotic events have culminated in some of the world’s profound and enduring political and social historical markers, the Magna Carta in 1215 AD and the murals of the Mogao Caves on the Silk Road come to mind. So too in science evolutionary processes bring together disorganized actions and reactions resulting in new order in the universe from thought processes, to new species to cosmic events such as super novas. Indeed, herding CATZ (Calipso And Twilight Zone) may one day will be considered (by some, probably few) as just such a marker. Given an ample supply of summer student energy, aerosol-cloud processes, Calipso and A-train data, ~15 NASA affiliated scientists willingness to try the unorthodox, three aircraft, and a variety of ground measurement resources from MPLNET, SMART, AERONET, MAN, SAM and Maryland crabs, CATZ will provide data for joint inversions for aerosol retrievals, provide data for analysis of the aerosol-cloud continuum, validation of the Calipso aerosol products, and assess new possibilities of lunar photometry and lidar retrievals. In this seminar I’ll at least explain the acronyms, discuss what data we’ve collected so far, identify who has the data and what ‘we’ hope to achieve. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room G133 DTSTART;TZID=US/Eastern:20071002T110000 SUMMARY:Svetlana Kotchenova: Radiative Transfer Codes for Atmospheric Correction and Aerosol Retrievals: Intercomparison Study DESCRIPTION:Svetlana Y. Kotchenova and Eric F. Vermote\n\nThe study is being performed in collaboration with: Robert Levy, Alexei Lyapustin, and Omar Torres\n\nRadiative transfer (RT) codes simulating the propagation of solar radiation through the atmosphere serve as cornerstones for passive remote sensing. One of their most significant applications is the calculation of look-up tables (LUTs) or pre-computed sets of radiance (reflectance) values for satellite data processing algorithms. Thus, one can say that the accuracy of LUTs directly depends on the code used for its creation. The general atmospheric RT code accuracy requirement for pure simulation studies is 1%. However, it would be interesting to find out if violation of this requirement had a significant effect on the resulted satellite product.\nTo answer this question, we have started a joint project devoted to the comparison and detailed evaluation of five atmospheric RT codes incorporated in different satellite data processing algorithms, namely: (1) 6SV1.1, which is the basic vector RT code of the MODIS atmospheric correction algorithm; (2) RT3, a polarized vector RT code which underlies the MODIS coarse-resolution (1-km) aerosol retrieval algorithm; (3) VPD (otherwise often called the Dave code), a relatively old IBM-based vector code used for the TOMS aerosol inversion; (4) SHARM, a scalar code underlying the MAIAC algorithm; and (5) MODTRAN, another scalar code which is widely used for the analysis of AVIRIS data.\n\nThe major goals of the project are: (1) to evaluate the accuracy of each code based on the comparison with standard benchmark references such as Coulson’s tabulated values and a Monte Carlo approach; (2) illustrate differences between individual simulations of the codes; (3) to determine how the revealed differences influence on the accuracy of aerosol optical thickness and surface reflectance retrievals; and (4) to create reference (benchmark) data sets that can be used in future code comparison studies. All information about this project can be found on the official project Web site at http://rtcodes.ltdri.org. The calculations are totally completed for 6SV1.1 and SHARM, and partially completed for RT3, VPD, and MODTRAN. END:VEVENT BEGIN:VEVENT LOCATION: DTSTART;TZID=US/Eastern:20071016T090000 SUMMARY:Clark Weaver: A Slow Retrieval Algorithm for Surface Based Instruments DESCRIPTION:I present results from a retrieval algorithm for ground based instruments using the Arizona radiative transfer code. A state vector describing the atmospheric and surface condition is iteratively modified until the calculated radiances match the observed values. Elements of the state vector include: aerosol concentrations, radius, optical properties, mass-weighted altitudes and surface reflectance BRDF. Both Almucantar and Principle plane radiances along with AOT observations from selected AERONET sites are used simultaneously to retrieve the state of the atmosphere and surface conditions. The retrieved aerosol size distributions and optical properties are consistent with the aerosol inversions from the AERONET group. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room F225 DTSTART;TZID=US/Eastern:20071019T110000 SUMMARY:CANCELLED - Dr. Heikki Lihavainen: Aerosol measurements at Pallas-Sodankylä Global Atmosphere Watch station DESCRIPTION:IMPORTANT: We are very sorry, but this event has been cancelled.\n\nFinnish Meteorological Institute's air quality measuring station at Pallas, northern Finland, has been part of the Global Atmosphere Watch program of the World Meteorological Organization since 1994. Continuous measurements of aerosol particle characteristics were started on 1996. The present instrumentation includes continuous measurements of total number concentration, size distribution, scattering and backscattering coefficients, aerosol black carbon concentration and aerosol optical depth. Also various trace gases and weather parameters are continuously monitored. In this presentation I will give an overview of the results of the aerosol measurements measurements. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room G133 DTSTART;TZID=US/Eastern:20071030T110000 SUMMARY:Ed Nowottnick: Use of A-Train and NAMMA Observations to Validate a New Dust Source Scheme in GEOS-4 DESCRIPTION:Annually, about 240 Tg of Saharan dust is transported across the Atlantic Ocean. Dust deposited to the surface provides nutrients that support the aquatic ecosystems of the Atlantic Ocean as well as the terrestrial ecosystems of South America, the Caribbean, and North America. Additionally, the long-range transport of dust is a potential source of pollutant particulate matter. Dust has an influence on the Earth radiation budget through scattering and absorption of radiation and modification of cloud properties. These radiative feedbacks potentially influence the cyclogenesis occurring off the west African coast. We have implemented a new dust source scheme in the NASA Goddard Earth Observing System (GEOS-4) atmospheric general circulation model and data assimilation system. Our dust source scheme is a more physically based scheme than previous incarnations of the model. Here we use A-Train observations from MODIS, OMI, and CALIPSO along with NAMMA LASE data to evaluate simulated dust distributions during 2006. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room G133 DTSTART;TZID=US/Eastern:20071113T110000 SUMMARY:Zia Ahmad: Atmospheric Correction for Visible and NIR Bands of the MODIS and SeaWiFS Sensors for Ocean Remote Sensing Studies DESCRIPTION:Satellite remote sensing of the ocean in the visible region of the spectrum, even under the best conditions, is very challenging. Radiative transfer simulations show that the contribution from the water-leaving radiance to the top-of-the atmosphere (TOA) radiance over deep ocean (depth >1000 m) is around 12 percent, and the contribution decreases to a few percent in the coastal areas like Chesapeake Bay. The retrieval of water-leaving radiance, in other words, requires subtracting one large number (atmospheric contribution) from another large number (the TOA radiance). Within the Ocean Biology Processing Group (OBPC) at NASA/GSFC, the remote sensing of the ocean is carried out by SeaWiFS and MODIS sensors. I will describe the atmospheric correction algorithm adopted by OBPG to retrieve water-leaving radiances, and other products like aerosol optical thickness (AOT) and chlorophyll concentration from the two sensors. In addition, I will talk about main features of the OBPG and MODIS-atmosphere aerosol algorithms, and show a comparison of the OBPG retrieved AOTs with AERONET data over the Chesapeake Bay where there is no MODIS-atmosphere aerosol product available. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room H114 DTSTART;TZID=US/Eastern:20071114T033000 SUMMARY:Dr. Mian Chin: Aerosol Absorption: From Pollution, Dust, and Biomass Burning DESCRIPTION:It is well known that aerosol absorption plays important roles in weather and climate, and yet the spatial distributions and radiative properties of absorbing aerosols remain largely uncertain. We present here a global modeling study of aerosol absorption in the atmosphere with an attempt to quantify the aerosol optical depth and single scattering albedo for climate studies. I will:\n\n- Compare aerosol optical properties from GOCART model calculation and AERONET measurements/retrievals at 131 AERONET sites in 2004.\n\n- Quantify spatial and temporal variation of absorption by pollution, dust, and biomass burning aerosols.\n\n- Discuss uncertainties in biomass burning emissions.\n\nI would also like to use this opportunity to get feedback for this study! END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room G133 DTSTART;TZID=US/Eastern:20071127T110000 SUMMARY:Dr. Mian Chin DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION: DTSTART;TZID=US/Eastern:20071218T090000 SUMMARY:Post_AGU Poster Session Event DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room H114 DTSTART;TZID=US/Eastern:20080107T110000 SUMMARY:Glenn Shaw: A Certain Slant of Light DESCRIPTION:This seminar is a nostalgic and historical look back to the science of radiometry, especially as practiced by Samuel Pierpont Langley and Charles Greeley Abbot, driven by their suspicion that the sun is a variable star. Their research unwittingly opened up the field of remote sensing. The author contends that this is still a scientifically fruitful field and will demonstrate this using data from spacecraft platforms and from home-built gadgets. END:VEVENT BEGIN:VEVENT LOCATION: DTSTART;TZID=US/Eastern:20080205T110000 SUMMARY:Alexander Marshak: The Apparent Bluing of Aerosols Near Clouds DESCRIPTION:Numerous studies based on satellite observations have reported that aerosol optical depths increase with increasing cloud cover. Part of the increase comes from the humidification and consequent growth of aerosol particles in the moist cloud environment, but part comes from 3D cloud-radiative transfer effects on the retrieved aerosol properties. Often, discerning whether the observed increases in aerosol optical depths are artifacts or real proves difficult. We describe a simple model that can quantify the enhanced illumination of cloud-free columns in the vicinity of clouds. This model is based on the assumption that the enhancement in the cloud-free column radiance comes from enhanced Rayleigh scattering that results from the presence of the nearby clouds. This assumption leads to a larger increase of AOT for shorter wavelengths, or to a "bluing" of aerosols near clouds. Examples from the MODIS observations that illustrate the apparent bluing of aerosols near clouds will be discussed. END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, G133 DTSTART;TZID=US/Eastern:20080219T110000 SUMMARY:Omar Torres: Use of OMI and A-train observations for accurate characterization of aerosol absorption DESCRIPTION:The Ozone Monitoring Instrument (OMI) on the Aura satellite is a hyper-spectral sensor that measures the backscattered radiation in the 270-500 nm spectral range. A variety of retrieval techniques are applied to retrieve total column ozone amount, tropospheric gas concentration and aerosols. The unique advantage of the OMI sensor for aerosol characterization is the availability of measurements in the near-UV that are used to measure aerosol absorption taking advantage of the interaction between the processes of molecular scattering and particle absorption. In this seminar I will discuss the retrieval approach, present evaluation results and discuss the potential of A-train applications to enhance the science value of the aerosol information derived from space-borne sensors. END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, room H114 DTSTART;TZID=US/Eastern:20080304T133000 SUMMARY:Aerosol Update DESCRIPTION:More Information\n\n1:30 PM - 4:30 PM. END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, H-120 DTSTART;TZID=US/Eastern:20080314T100000 SUMMARY:Jeffrey Pierce: Ultrafine atmospheric aerosols, clouds and climate DESCRIPTION:Atmospheric aerosol regulates climate by scattering and absorbing radiation and by altering the radiative properties of clouds. Estimates of how humans are affecting the energy balance of the planet are uncertain largely due to complicated interactions between aerosols and clouds. A major factor in this uncertainty is the how humans have\nchanged the number of particles in the atmosphere that may act as cloud condensation nuclei (CCN). Ultrafine particles (particles with diameters smaller than 100 nm), are often too small to act as CCN; however, a large fraction of particles in the atmosphere begin as ultrafine particles and must grow to CCN sizes. In this talk we will explore how uncertainties in ultrafine aerosol sources, such as nucleation and emissions from primary sources, lead to uncertainties in predictions of CCN concentrations and cloud albedo. The impact of these ultrafine particles on CCN will be explored using both a simple model of aerosol timescales as well as a detailed 3-D general circulation model with detailed aerosol microphysics. The importance of reducing uncertainties in primary particle emission rates as well as new particle formation rates in predictions of cloud albedo are assessed. Finally we explore the potential link between cosmic ray intensity and cloud properties through changes in ion-induced new particle formation rates.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, F-225 DTSTART;TZID=US/Eastern:20080318T110000 SUMMARY:Ralph Kahn: How much information about aerosols can we expect from passive satellite observations? DESCRIPTION:For nearly eight years, we have been squeezing the NASA Earth Observing System's MISR and MODIS data to learn everything we can about particles in the atmosphere. We have discovered quite a lot concerning the horizontal and even the vertical distribution of aerosol amount, something about aerosol type distribution, and a little regarding multi-year temporal variations. Further refinements of these products can be expected over the coming few years. However, there are also some significant gaps in our knowledge that appear difficult to remove with satellite observations alone. These range from near-surface chemical speciation, critical for some health applications, to quantitative assessments of long-term trends. I will summarize how far we've come, how much farther I think we can go with the satellite data themselves, and what efforts might help fill some of the gaps that matter most to key environmental applications.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Room G133 DTSTART;TZID=US/Eastern:20080325T110000 SUMMARY:Tom Zhao: Study of Long-term Trend in Aerosol Optical Thickness Observed from Operational AVHRR Satellite Instrument DESCRIPTION:The long-term trend of aerosol optical thickness (AOT) over the global oceans has been studied by using a nearly 25-year aerosol record from the Advanced Very High Resolution Radiometer (AVHRR) Pathfinder Atmosphere extended (PATMOS-x) data set. Both global and regional analyses have been performed to derive the AOT tendencies for monthly, seasonal, and annual mean AOT values at AVHRR 0.63um channel (or Channel-1). A linear decadal change of -0.01 is obtained for globally and monthly averaged aerosol optical thickness of AVHRR Channel-1. This negative tendency is even more evident for globally and annually averaged AOT and the magnitude can be up to -0.03/decade. Seasonal patterns in the AOT regional long-term trend are evident. In general, negative tendencies are observed for seasonally averaged AOT in the regions influenced by the emissions from industrialized countries and the magnitude can be up to -0.10/decade. Positive tendencies are observed in the regions influenced by the emissions from fast developing countries and the magnitude can be up to +0.04/decade. For the regions heavily influenced by Saharan desert particles, a negative trend with a maximum magnitude of -0.03/decade is detected. However, over the regions influenced by the smoke from biomass burning, positive tendencies with a maximum magnitude of +0.04/decade are observed. Sensitivity analyses have also been performed to study the effects of radiance calibration, aerosol retrieval algorithm, and spatial resolution of input retrieval radiances on the global aerosol long-term tendencies. END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, G-133 DTSTART;TZID=US/Eastern:20080401T110000 SUMMARY:Warren Wiscombe: My Experiences as an AGU Council Officer DESCRIPTION:Four years ago, and to my great surprise, I was elected as President of the AGU Atmospheric Sciences Section. Unlike many on the AGU Council, I had not had considerable experience with the organization, and thus many of those things which others took for granted were new to me. This will be the story of my learning the ins and outs of this remarkable organization, and of the things I was able to accomplish (mostly within the Section), and those I was stymied on (mostly within the Council). \n\nAGU is in a period of transformation right now. Some of the transformational issues I will touch upon are:\n* transition to all-electronic publishing, and "the DOI problem";\n* the Eos house organ;\n* exponential growth in Fall meeting attendance; \n* structure of the Council, and the rapid growth of the non-hard-rock Sections;\n* the funding model for AGU, and the fund-raising drive.\n\nI came away with an impression of a remarkably healthy organization which prospers because of the almost unbelievable amount of volunteerism, ranging from those who organize the meetings to those who edit the journals to those who chair and serve on the numerous AGU committees. This is where the real action in AGU is; the Council is not, although as a result of our Section's various motions, the Council was less sleepy than usual during my tenure.\n\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. G-133 DTSTART;TZID=US/Eastern:20080415T110000 SUMMARY:David Giles: Characterizing Aerosols over Southern Asia using the AERONET Data Synergy Tool (Training exercises also provided) DESCRIPTION:The AERONET Data Synergy Tool web portal (http://aeronet.gsfc.nasa.gov) was developed with initial support from REASON CAN to provide value-added Earth Science data sets pertinent to aerosol research. The data synergy tool provides ground-based, satellite, and model data products to characterize aerosol optical and microphysical properties, spatial and temporal distribution, transport, and chemical and radiative properties. The synergy tool structure relies on data partners to maintain the production, transfer, and quality of these data products (e.g., GIOVANNI). Each data product is temporally-independent and associated with a specific AERONET site, while satellite and model products provide greater geographic range around these sites. The tool currently provides data products from AERONET, MPLNET, MODIS, TOMS, OMI, SeaWiFS, GOCART, NOGAPS, Solrad-net and kinematic back trajectory analyses. In general, each data product provides a graph or map and the ability to download these data with custom data controls (e.g., version, level, and resolution). Sun photometer spectral aerosol optical depth measurements as well as microphysical and optical aerosol retrievals over Southern Asia will be analyzed and discussed with supporting ground-based, satellite, and model data sets obtained from the AERONET Data Synergy tool. Furthermore, synergy tool training exercises will be provided to show how the tool can be used for aerosol analysis. \n\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20080425T110000 SUMMARY:Edward Hyer: Evaluation of MODIS over-land retrieved AOD for use in a data assimilation system DESCRIPTION:Measurement and characterization of atmospheric aerosols poses a unique challenge to the capabilities of passive sensors operating in the visible and near-infrared. The MODIS instruments, with their combination of frequent coverage and high radiometric and spectral resolution, offer the best capabilities of any current or planned sensor for aerosol monitoring in near-real time. For these reasons, the MODIS aerosol retrieval was chosen for a project to assimilate satellite retrievals of aerosol optical depth (AOD) into the Navy Aerosol Analysis and Prediction System (NAAPS). Under the auspices of this project, researchers at the Naval Research Laboratory have developed an aerosol data assimilation system (NAVDAS-AOD) based on 2-D variational assimilation of AOD from satellite. This system was built and tested using over-ocean AOD data, and provides substantial improvement in aerosol forecast skill. \nThe next phase, described in this talk, is to incorporate over-land AOD into the data assimilation system. After a brief overview of the AOD data assimilation system, we describe some results from our efforts to characterize the MODIS Collection 5 AOD retrieval over land. With strict QA filtering, we achieved a substantial reduction in the scatter of the AOD retrieval (>20% reduction in RMSE vs. AERONET sunphotometer AOD), but at a high cost in data volume and coverage. We discuss the tradeoffs involved in the context of a real-time aerosol forecasting application.\nOur results in terms of random error and overall global accuracy are quite satisfactory, but substantial regional biases remain in the MODIS AOD product. These biases result from two major causes: surface boundary condition and aerosol microphysical properties. We are using the MODIS albedo product to diagnose and quantify AOD retrieval biases related to the surface boundary condition. This is complicated by residual AOD contamination in the retrieved albedo data, as well as geographic covariance of albedo and AOD. These factors make it difficult to confidently specify the likely extent of either microphysical or surface-boundary bias. This talk concludes with a discussion of the difficulty of separating error sources, and implications for improvement of satellite AOD retrievals.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. G-133 DTSTART;TZID=US/Eastern:20080429T110000 SUMMARY:Franco Einaudi: The Role of the AMS DESCRIPTION:I will describe the functions of the AMS, ranging from being responsible for the quality of its journals and conferences (scientific communication), to the educational and outreach function (support for students and K-12 education), to the communication with the policy makers and the general public.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. G-133 DTSTART;TZID=US/Eastern:20080617T110000 SUMMARY:Chieko Kittaka: Toward the synergy of aerosol modeling, MODIS AOD and CALIPSO DESCRIPTION:Air quality models have become a powerful tool to diagnose and predict three-dimensional distributions of aerosol species. The model performance with dust and smoke is, however, not as good as that with sulfate aerosol. This is because dust and smoke events are episodic and it is difficult to characterize their emissions. Consequently, these aerosol constituents introduce large uncertainties in modeled aerosol distributions. Assimilation of MODIS AOD within an aerosol forecast model makes it possible not only to understand the current aerosol distribution but also to predict it with constraints from the satellite observations. The first half of this talk presents an assessment of the improvement in aerosol predictions due to the incorporation of MODIS AOD in a regional aerosol forecast model. The Real-time Air Quality Modeling System (RAQMS) with a MODIS AOD assimilation is used to simulate the aerosol distributions for Aug - Oct, 2006, when dust is transported from Sahara to the Gulf of Mexico and smoke is emitted from biomass burning over the Pacific Northwest. The model performance is evaluated using the CALIPSO observations for assessing vertical profiles and the EPA AIRNow data for assessing the surface distribution. An impact of the MODIS AOD assimilation on each aerosol species is analyzed. Further improvement of the MODIS AOD assimilation is also discussed. The second half of this talk focuses on the CALIPSO aerosol products. The global CALIPSO aerosol extinction distributions will be presented and discussed along with the comparison with the MODIS AOD product.\n\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, E-108 DTSTART;TZID=US/Eastern:20080812T110000 SUMMARY:Francois-Marie Breon: Polarization in Earth Remote Sensing: Aerosol monitoring and more… DESCRIPTION:The POLDER and Parasol instruments measure the directional and polarization signatures of the Earth reflectances. The primary use of these signatures is for aerosol monitoring. Indeed, polarization is a great tool to measure aerosols over land surfaces although the POLDER concept has some limitations that may be solved with the forthcoming APS instrument onboard the GLORY satellite. There are other use of the polarization, in particular for cloud phase, cloud drop size and ice plate orientations. The seminar will make a broad presentation of polarization signatures as they have been observed by POLDER and Parasol, and what use has been made of it.\n\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. H-114 DTSTART;TZID=US/Eastern:20080815T110000 SUMMARY:Brendan DeLacy: The Determination of Carbon Dioxide Concentration Using Atmospheric Pressure Ionization Mass Spectrometry And Maximizing Visible and Infrared Mass Extinction Coefficients DESCRIPTION: The development of an atmospheric pressure ionization mass spectrometry/isotopically labeled standard (APIMS/ILS) method for the determination of carbon dioxide (CO2) concentration will be discussed in the first part of the presentation. Descriptions of the instrumental components, the ionization chemistry, and the statistics associated with the analytical method will be described. The APIMS/ILS method represents an alternative to the nondispersive infrared (NDIR) technique which is currently used in the atmospheric community to determine atmospheric CO2 concentrations. Both the APIMS/ILS method and the NDIR method are subject to moisture interferences. To circumvent these interferences, a dryer such as a Nafion dryer is used to remove water prior to detection. The APIMS/ILS method measures mixing ratios and demonstrates linearity and range in the presence or absence of a dryer. The NDIR technique on the other hand measures molar concentrations. Errors in molar concentration measurements that are caused by drying will be discussed. An equation describing the errors was derived from the ideal gas law, the conservation of mass, and Dalton’s Law. The purpose of this derivation was to quantify errors in the NDIR technique that are caused by drying. Laboratory experiments were conducted to verify the errors created solely by the dryer in CO2 concentration measurements post-dryer. The laboratory experiments verified the theoretically predicted errors in the derived equations. The impact that these errors have on flux measurements will also be discussed.\n The second part of the presentation will focus on the improvement of visible and infrared obscurant aerosol materials. The U.S. Army currently has a need to improve the visible and infrared attenuation properties of obscurants in order to provide enhanced screening capabilities for soldiers and platforms from both visible and infrared (electro-optic) threats. Theoretical aspects of visible and infrared obscuration will be discussed in the context of material development. Additionally, challenges associated with material fabrication, including particle agglomeration and surface modification, will be discussed. A description of a 190 m3 aerosol test chamber, mass extinction coefficient measurements, and the impact of dissemination techniques (pneumatic and explosive) on extinction measurements will be provided. Finally, alternative material development involving Expancel microspheres and carbon nanorods will be discussed.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. H-114 DTSTART;TZID=US/Eastern:20080822T110000 SUMMARY:Zahra Chaudhry: Optical, Chemical, and Physical Properties of Aerosols from In Situ Measurements in China DESCRIPTION:The rapid population and economic growth seen in China over the last few decades has had strong effects on the local and regional air quality and climate. Several intensive studies have been conducted to examine the transport of air masses from the region over the Pacific, such as ACE-Asia and INTEX-NA. The East Asian Study of Tropospheric Aerosols: an International Regional Experiment (EAST-AIRE) takes a closer look at the physical, optical and chemical properties of aerosols across China through a series of ground-based observation stations. As a part of the EAST-AIRE study, ground-based Nuclepore filters were collected in two size ranges (coarse, 2.5um 800 km or so, but closer to -5/3 at scales < 500 km, as observed by various aircraft campaigns and shown by numerical modeling and theoretical studies. The temperature exponent in the tropics at all length scales becomes less negative and is larger than -5/3. For water vapor, the scaling relationships are vastly different from temperature with -5/3 observed in the midlatitudes, and less than -2 in parts of the tropics and subtropics, with little to no scale break observed. Lastly, we investigate the statistical moments of cloud water content (CWC) fields observed by Cloudsat for multiple cloud-types coincident to AIRS. The various moments of CWC distributions reveal coherent altitude, latitudinal, and cloud-type structures that will be useful to constrain assumptions about sub-grid scale distributions of cloud properties in statistical climate model parameterizations.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. H-114 DTSTART;TZID=US/Eastern:20080919T110000 SUMMARY:Rob Levy: Retrieving global aerosol properties from MODIS: The challenge of the climate data record DESCRIPTION:Aerosols, produced by both natural and anthropogenic processes, are integral in Earth’s climate system. They perturb the radiative budget and hydrologic cycle, through complicated interactions with clouds and the Earth’s surface. Understanding global aerosol distributions, variability and trends are a necessary step in understanding how the climate is changing. Deriving a quantifiable, comprehensive, and long-term global aerosol data record is a primary goal for NASA. \n \nWith its launch aboard Terra in late 1999, MODIS ushered in a new era of global aerosol monitoring. In particular, due to its extensive spectral range, wide viewing swath, and fine spatial resolution (1 km or better), MODIS is capable of providing an accurate and dependable global aerosol optical depth (AOD) data set. MODIS’s AOD products are freely and easily available from NASA, and are currently being accessed by hundreds of users around the world. Production of such a high quality aerosol dataset has required an extensive production team, of which I am proud to have been a part of for the past ten years. As the principal developer of the “second generation” algorithm for retrieving aerosol over dark land surfaces, I guided it from conception, to implementation and finally to validation of its derived products. However, it still must be improved in order to provide climate data quality records. My talk will highlight my contributions to the MODIS related aerosol effort as well as suggest steps towards attainment of climate-quality aerosol data. \n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20081002T110000 SUMMARY:Richard A. Ferrare, Chris Hostetler, John W. Hair, Raymond R. Rogers, Mike Obland, Sharon P. Burton, Wenying Su, Jay Al-Saadi, Jim Szykman, Anthony L. Cook, David B. Harper: THE NASA LANGLEY RESEARCH CENTER AIRBORNE HIGH SPECTRAL RESOLUTION LIDAR: AEROSOL OBSERVATIONS AND APPLICATIONS DESCRIPTION:In this presentation we discuss the High Spectral Resolution Lidar (HSRL) technique and the performance characteristics and applications of the the NASA Langley Airborne HSRL. Observations and analyses from nine field missions dating back to 2006 will be presented. Applications of the data include satellite validation, identification of boundary layer height, aerosol typing and partitioning optical depth by type, assessment of chemical transport models, and studies of aerosol-cloud interactions. We will also discuss the multi-wavelength HSRL that is currently under development at Langley. END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20081007T110000 SUMMARY:Yunha Lee: Development of a global aerosol microphysics model for aerosol indirect effects DESCRIPTION:Aerosols enhance cloud albedo and modify precipitation efficiency by acting as cloud condensation nuclei (CCN) (Twomey, 1974; Albrecht, 1989). These two aerosol indirect effects (AIEs) are the most uncertain climate forcings. Traditionally, global models used to estimate these AIEs have had overly simplified and highly empirical treatments of aerosols and cloud processes. This seminar will describe the development and evaluation of a next generation global model with a sophisticated and physically-based treatment of aerosol-cloud interactions. Our tool is the TwO-Moment Aerosol Sectional (TOMAS) aerosol microphysics algorithm implemented into the Goddard Institute of Space Study General Circulation Model II’ (GISS GCM II’) (Hereafter, GISS-TOMAS model). \nSeveral model development and evaluation activities will be discussed. First, a mineral dust aerosol model is developed for GISS-TOMAS, evaluated with surface measurements, and its impacts on CCN assessed. Second, we evaluate the global distribution of aerosols in GISS-TOMAS against AOD from MODIS, MISR and AERONET. Third, to accomplish the multi-year simulations required to assess AIE, we improve the computational efficiency of GISS-TOMAS by a factor of three with minimal loss in accuracy. Finally, a state-of-the-art cloud microphysics model is implemented to simulate activation (the formation of cloud droplets from aerosol particles) and autoconversion (formation of precipitation from cloud droplets). \n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20081021T110000 SUMMARY:Dilip Ganguly: Constraining the composition and concentration of aerosols in a GCM using AERONET, MPLNET and satellite data DESCRIPTION:A realistic assessment of the impact of aerosols on climate demands climate models to simulate correct distribution of aerosols in the atmosphere around the globe. MODIS and CALIOPE together provide a 3-dimensional view of aerosol distribution in the Earth's atmosphere. Here I will demonstrate a technique of deriving the concentration of aerosol components by minimizing the differences between computed and observed values of parameters like AOD, single scattering albedo, size distribution and vertical profile of aerosols. As some of these parameters are not available through satellite retrievals, we applied our technique over the United States using the data from AERONET and MPLNET stations. The results are validated using ground-based measurements of aerosol concentration from IMPROVE and EPA networks. I will then show how these results are used to improve GFDL-AM2 climate model simulations. Finally, I will talk briefly about my work in progress of combining this technique with MODIS, CALIOPE and OMI data to improve the simulated of aerosol distribution over south Asia in order to understand their impact on the climate over this region.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg 33, Rm. F-225 DTSTART;TZID=US/Eastern:20081118T110000 SUMMARY:Susanna Bauer: Sensitivity of Climate Forcings to Aerosol Microphysics DESCRIPTION:Aerosol effects on climate are sensitive to their composition, size and mixing state, however the character of atmospheric aerosols remains poorly constrained. A new detailed aerosol microphysical scheme, MATRIX, embedded within the global GISS modelE climate model provides the capability to probe a large range of possible aerosol climatologies, and then explore how these variations would affect climate.\n\nAerosols are directly released as particles or formed through secondary particle formation in the atmosphere. Condensation and coagulation processes lead to further aerosol growth, aging and internal mixing. Those aerosol characteristics determine their role in direct and indirect aerosol forcing, as their chemical composition and size distribution determine their optical properties and cloud activation potential. MATRIX includes the above processes that determine the lifecycle and climate impact of aerosols.\n\nThis study presents a quantitative assessment of the impact of single microphysical processes, such as nucleation, coagulation, emission size distributions etc. on aerosol cloud activation and radiative forcing. For example the different parameterization of new particle formation through ternary or binary nucleation theory can change the number concentration of cloud activating particles regionally by up to 20%. This study will summarize the sensitivity of aerosol-climate interactions to microphysical parameterizations.\n\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20081202T110000 SUMMARY:Richard Kleidman: MODIS and A-Train Professional Training and Outreach Activities DESCRIPTION:NASA spends millions of dollars to create the Earth Science data products that we all work so hard to produce. We spend millions more to archive and make the data available. Unfortunately there is very little money spent on professional outreach and training to show those unfamiliar with the products how to understand, obtain and use the data properly. Since January 2007 I have taught (with the help of many others) several MODIS Data Workshops in order to address this omission. I plan to give an overview of these workshops as well as share what I see as the strengths and weaknesses in the systems we have created to facilitate the study of Earth Science. Last but not least I hope to encourage your input and participation in future outreach and training activities. \n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. E-125 DTSTART;TZID=US/Eastern:20081209T110000 SUMMARY:Alexander Smirnov: Maritime Aerosol Network (MAN) as a component of AERONET – first results. DESCRIPTION:We present a concept of a Maritime Aerosol Network of hand-held sunphotometers. The proposed activity includes deployment of hand-held sunphotometers at sea and measurements from various ships of opportunity. Overall it will complement island-based AERONET measurements. Scientific objectives of this kind of activity are primarily climate change studies (direct and indirect forcing); satellite retrievals validation; validation of global aerosol transport model simulations; atmospheric correction in ocean color studies; and also questions of the existing gaps in global aerosol distribution and how representative are the island measurements. Accomplished cruises included transects from Northern to Southern Atlantic, from New Zealand to Japan, measurements in the Southern Ocean, near the coast of Antarctica, in the Mediterranean Sea, Gulf of Botnica, Beafort Sea and in Barents and Greenland Sea. First results are presented.\n END:VEVENT BEGIN:VEVENT LOCATION: DTSTART;TZID=US/Eastern:20090114T090000 SUMMARY:Min M. Oo, Ana Picon, Eduardo Hernandez, Matthias Jerg, Barry M. Gross, Fred Moshary and Samir A. Ahmed : Improved MODIS aerosol retrieval using modified VIS/MIR surface albedo ratio over urban scenes DESCRIPTION:Determination of Aerosol Optical Depth (AOD) by satellite remote sensing measurements over land is complicated by the fact that the Top of Atmosphere (TOA) reflectance is a combination of the desired atmospheric path reflectance as well as the ground reflectance. Unfortunately, inaccurate surface modeling results in inaccurate AOD retrieval as well as reducing spatial resolution. In this presentation, we primarily focus on the use of simultaneous MODIS and AERONET sky radiometer data to refine the surface albedo models regionally and improve on the current AOD operational retrieval. In particular, we show that the correlation coefficient assumption used in the MODIS Collection (5) model between the VIS and MIR channels used for surface reflection parameterization in urban areas such as New York and Mexico City is severely underestimated. This is demonstrated both directly using high spatial imagery data from Hyperion and indirectly by constraining MODIS TOA reflection data with AERONET Sky radiometer AOD retrievals. In particular, we find that combining the satellite and radiometer measurements allows us to generate a regional VIS/MIR surface reflectance correlation coefficient map at spatial resolutions up to 1.5km. Application of the regional VIS/MIR surface reflectance ratio model is shown to completely remove the bias and reduce uncertainty at the operational resolution of 10km as well as at higher resolutions to 1.5km resolution. Finally, spatial AOD retrievals using the surface albedo model are developed within the MODIS operational software showing the reduction in artificial AOD hotspots. In addition, we explore the angular dependence of the surface albedo. In particular, we find that the correlation coefficients are insensitive to scattering angle as expected MODIS and errors in using a Lambertian assumption are shown to be less than the errors associated in the albedo variability. Additional current and future work includes the comparison of MISR retrieved AOD with AERONET derived AOD over urban areas. Moreover, we plan to apply modified surface models to GOES satellite observations and compare to GASP aerosol and surface retrievals. END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20090120T110000 SUMMARY:Allen Chu DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20090127T110000 SUMMARY:Lazaros Oreopoulos: Inferring warm cloud susceptibility from MODIS DESCRIPTION:Satellite studies of the indirect effect remain challenging due to the\ndifficulties involved in trying to quantify a change in cloud properties due\nonly to changes in aerosol amount and type, while all other factors that\naffect cloud properties remain fixed. In other words, it is exceedingly\ndifficult to envision sorting out a “controlled experiment” from\nobservations of a very complex and changing system. Further, the response of\nthe cloud depends on the cloud properties that existed before being modified\nby the presence of aerosol (that is, not all clouds respond the same).\nRather than confronting the formidable task of assessing the indirect effect\non cloud properties at a particular place and time, we adopt an alternative\napproach where satellite retrievals are used to estimate the cloud radiative\nsensitivity (or susceptibility) to a specified change in cloud particle\nnumbers. An understanding of this sensitivity can then be used to specify\nthe regions of the globe where the radiative indirect effect might be more\nsignificant and assist in climate model validation and interpretation.\nIn the presentation I'll explain how we quantify the potential indirect\nradiative effect of aerosols on solar radiation using liquid water cloud\nproperties provided by the MODIS instrument onboard the NASA Terra and Aqua\nsatellites. Individual high spatial resolution data is analyzed as well as\nglobal data for four months. The analysis includes the effect of land\nsurface albedo and atmospheric absorption and demonstrates that in addition\nto the cloud’s properties, the location and environment in which the cloud\nforms is also critically important. We also provide global estimates of what\nwe call "susceptibility forcing" for a few droplet density perturbation\nscenarios.\n END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20090203T110000 SUMMARY:Ellsworth Judd Welton DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20090217T110000 SUMMARY:Hongbin Yu DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20090331T110000 SUMMARY:Eric Wilcox DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20090414T110000 SUMMARY:Zhanqing Li DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20090428T000011 SUMMARY:Santiago Gasso' DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20090512T110000 SUMMARY:Jeff Reid DESCRIPTION: END:VEVENT BEGIN:VEVENT LOCATION:Bldg. 33, Rm. F-225 DTSTART;TZID=US/Eastern:20090609T110000 SUMMARY:Allen Chu DESCRIPTION: END:VEVENT END:VCALENDAR