US Dept of Commerce
NOAA /
OAR /
PMEL
PMEL Programs for FY 99 and Plans for FY 00
Tropical Atmosphere-Oceans Program
Accomplishments in FY 99
Work at PMEL during the past year has included description and
diagnosis of physical mechanisms responsible for the 1997-98 El Niño,
which was among the strongest on record. This work has highlighted the
importance of intraseasonal atmospheric forcing in affecting the
amplitude and onset of the event. A cover story in Science magazine
described the interplay between the physics, biology, and chemistry of
the tropical Pacific during the 1997-98 El Niño using data from the TAO
array, NOAA ships, and from spaceborne sensors. Other studies have examined
the upper ocean mass, heat, momentum, and fresh water balances in the
upper equatorial Pacific Ocean using TAO and related data sets. These
studies have illustrated the complex mix of mechanisms that give
rise to observed variability on a wide range of time scales (diurnal,
intraseasonal, seasonal, and interannual) of relevance to climate.
In FY 99, refinements of the Next Generation ATLAS moorings continued,
and the number of sites in the array instrumented with this new
technology increased from 11 to 24. Moored bio-optical, nutrient and chemical
sensors were maintained at a few sites in collaboration with the NOAA Ocean
Atmosphere Carbon Exchange Studies (OACES) Program and the NASA SeaWifs
(ocean color) satellite program. The TAO project also continued a short
wave radiation measurement program in the western Pacific in
collaboration with the US Department of Energy/Atmospheric Radiation Measurements
(DOE/ARM) program, and an in situ rainfall and surface salinity
measurement program with the NASA Tropical Rainfall Measuring Mission (TRMM)
program. The TAO project also participated in two special field studies in FY 99,
the DOE/ARM NAURU99 Experiment and the NASA/TRMM KWAJEX Experiment.
Surface salinity measurements were maintained between 156E and the date
line, supported in part by the French Institut de Recherche pour le
Developement. Implementation of the Pilot Research Moored Array in the
Tropical Atlantic (PIRATA) continued in collaboration with Brazil and
France, with the array expanding from five to eleven sites. Two high
latitude ATLAS moorings, transmitting via GOES, were successfully
deployed in the North Pacific at Ocean Station PAPA (50N, 145W) and Station MOMMA
(35N, 165W) as part of the National Ocean Partnership Program.
In all, TAO used 434 sea days on 7 ships from 5 countries to deploy 93
moorings. TAO personnel spent 932 person days at sea on cruises during
this time.
Thermal Modeling Analysis Project
Accomplishments in FY 99
- El Niño global ocean surface anomaly composite, and robust
features, published. There are many common features of the last
ten events. The most variability occurs during the Onset and
Decay phases of the events, but they have many similarities once
they get started. No statistically significant case can be made
that recent events differ from other post-WWII events. (Harrison
and Larkin, Rev. of Geophys)
- US statistically significant seasonal weather anomalies (and
extreme anomalies) associated with El Niño events described and
compared with the anomalies of the 97-98 El Niño. Although there
are statistically significant anomalies over 90% of the US in
either temperature or precip in one or more of Autumn, Winter and
Spring, only a few regions in a few seasons have anomalies really
strongly linked to El Niño. These regions, seasons, and
anomalies are described. (Harrison and Larkin, GRLet)
- A new mechanism for the end-phase of El Niño events, which
depends on the seasonal shift of warmest SST south of the equator
and the observed SST-zonal wind anomaly connection, has been
described. Simple model experiments suggest that the effect may
be more important than delayed oscillator reflected waves in
creating the central and eastern Pacific thermocline shallowing
that appears to precede the end of El Niño events. (Harrison and
Vecchi, GRLet)
- A strong association between anomalies of NPac storm tracks,
blocking events and high-zonal index periods and the SSTA over
the core of the PDO region has been identified. NCEP/NCAR
Reanalysis turbulent heat fluxes suggest that flux anomalies are
substantial and that they are of a sign so as to try to remove
the SSTA. (Bond and Harrison (GRLet)
- The SST changes following Westerly Wind Events have been
evaluated. There is cold tongue warming following Type W and C
WWEs, if the ocean was normal or cooler than normal initially.
And the ocean remains warmer than normal following them, if it
was warmer than normal initially. In the absence of WWEs the
ocean SST returns toward climatology. Because the mechanisms for
these types of behavior have been described via model studies of
the equatorial Pacific, it is suggested that WWEs are a key
element of atmospheric variability for the onset and maintenance
of El Niño conditions. (Harrison and Vecchi, Vecchi and
Harrison, J.Climate)
- The statistically significant ocean surface anomalies during
the Cold Phases of ENSO have been described and their robustness
evaluated. While there are many similarities between Cold and
Warm phases in the tropical Pacific the extra-tropical Pacific
anomalies show many differences. There are stronger and
longer-lived anomalies in the North Pacific, the tropical Indian
and the tropical Atlantic oceans during Cold events than during
Warm events. (Larkin and Harrison, J. Climate).
Atmospheric Chemistry Program
Accomplishments in FY 99
The Atmospheric Chemistry Program at PMEL is a measurement-based program designed to
improve the accuracy of estimates of climate forcing by tropospheric aerosol particles.
Specific goals of the program are to
i) determine the physical, chemical, and meteorological processes that
control the shape and magnitude of the aerosol number size distribution, aerosol
chemical composition as a function of particle size, and aerosol light scattering and
absorption,
ii) determine the spatial and temporal variability of these parameters, and
iii) compile a data base of aerosol parameters essential to the estimation of
aerosol radiative forcing that encompasses a wide range of geographical regions.
This information is needed to detect regional and global climate change, to attribute
that change to anthropogenic aerosols, and to improve the prediction of future climate
changes for various radiative forcing scenarios.
PMEL plays a lead role in the planning and execution of the
Aerosol Characterization Experiments (ACE) of the International Global Atmospheric Chemistry Project (IGAC).
ACE 1 took place in the remote marine atmosphere
south of Australia in order to characterize aerosol properties in a minimally polluted
environment. The ACE 1 Special Sections of the Journal of Geophysical Research were
published in FY 98 and FY 99 with papers describing the chemical, physical, radiative,
and cloud nucleating properties of aerosols over the remote ocean and the controlling
processes. These data currently are being used to develop aerosol process models.
ACE 2 focused on the radiative effects and processes
controlling anthropogenic aerosols from Europe and desert dust from the Africa as they
were transported over the North Atlantic Ocean. The experiment, which took place in
June/July 1997, involved over 250 research scientists from Europe and the United States.
It included 60 coordinated aircraft missions with six aircraft, one ship, five satellites,
and ground stations on Tenerife, Portugal and Madeira. NOAA-PMEL coordinated the shipboard
measurements aboard the Ukranian Research Vessel, Professor Vodyanitskiy. The initial results
from ACE 2 have been summarized in 48 research articles that have been submitted to Tellus
for a special issue that will appear
in early 2000. Highlights of the NOAA results include:
(1) The background submicron aerosol measured over the Atlantic Ocean during ACE 2 was more
abundant (number and volume) and appeared to be more aged than that measured over the Southern
Ocean during ACE 1. The submicron aerosol number size distributions in the air masses that
passed over Northern Europe, the Mediterranean, and coastal Portugal were distinctly different
from each other and the background aerosol. The differences can be attributed to the age of
the air mass and the degree of cloud processing. (2) Larger sulfate aerosol concentrations
were measured in the ACE 2 region than the ACE 1 region during periods of both continental and
marine flow. Concentrations during marine flow were about 4 times larger during ACE 2 than
during ACE 1. Continental concentrations during ACE 2 were an order of magnitude larger than
ACE 2 marine concentrations. The higher concentrations during marine flow most likely were a
result of a more continentally-impacted North Atlantic compared to the Southern Ocean and the
longer aerosol lifetimes in the ACE 2 region. Submicron and supermicron sea salt concentrations
were similar during ACE 1 and ACE 2. (3) During ACE 1 sea salt controlled the optical
properties of both the sub- and supermicron aerosol. Sea salt had a relatively smaller
influence on aerosol optical properties during ACE 2 because of the large concentrations
of submicron continental (mainly sulfate) aerosol. The smaller role of sea salt during ACE 2
was observed in several measured aerosol optical properties. The spectral dependence of light
scattering by particles indicated the strong influence of smaller fine mode rather than larger
coarse mode particles during ACE 2. The single scattering albedo indicated the presence of a
more absorbing aerosol than sea salt during ACE 2. (4) The amount of carbon-containing aerosol
and the identity of the carbon species are large unknowns that contribute to the uncertainty
in estimates of aerosol radiative forcing. A previous IGAC experiment in the Western Atlantic
(TARFOX) found sulfate to total carbon ratios of 1.6 +/- 0.7 at altitudes below 300 m. Shipboard
measurements during ACE 2 revealed a ratio of 2.9 +/- 1.3. The average sulfate concentrations
from the two regions were comparable but the total carbon concentration during TARFOX was
larger. This type of data helps us start to understand differences in the aerosol chemical
composition for different ocean regions.
Data from PMEL atmospheric chemistry cruises in the Pacific and Southern Oceans were compiled
and summarized to show that, for the entire central Pacific from 55°N to 70°S, sea salt dominates
the aerosol mass concentration in the marine boundary layer with a significant fraction occurring
in the submicron size range. Because of the high scattering efficiency of submicron sea salt
and its relatively long lifetime, sea salt is major contributor to scattering by the aerosol
in marine regions. It was estimated that in the tropics, outside of the ITCZ, sea salt can
account for 80 to 90% of the aerosol optical depth. These results
were reported by Quinn
and Coffman (1999).
The PMEL atmospheric chemistry group spent 106 days at sea during FY 99 aboard the Ronald H.
Brown participating in the AEROSOLS, INDOEX and
NAURU projects. Our participation in these projects
enabled us to collect an extensive data set of aerosol properties in different air masses
included background marine, desert dust, biomass burning, and North American, African and
Asian urban plumes.
Carbon Dioxide Program
Accomplishments in FY 98
Carbon dioxide is one of the most important gases in the atmosphere affecting the radiative balance of the earth. Atmospheric CO2
concentrations in the past 400,000 years have oscillated from around 200 to 280 ppm. Current atmospheric concentrations are
now around 367 ppm as a result of industrial and agricultural activities. In the past few decades, only half of the CO2 released by
human activity has remained in the atmosphere; on average, about 30% of the CO2 is taken up by the ocean and about 20% by the
terrestrial biosphere. Because carbon reservoirs in the ocean, atmosphere and terrestrial biosphere are irrevocably linked, the CCSP
calls for an integrated approach to studying the carbon cycle. The ocean plays a critical role in the global carbon cycle since it has a vast
reservoir of CO2 containing approximately 50 times more CO2 than the atmosphere, and therefore, exerts a controlling influence on
atmospheric levels.
The primary objective of NOAA’s Global Carbon Cycle (GCC) Program is to quantitatively assess the fate of CO2 in the atmosphere
and oceans. In order to accomplish this goal the natural sources and sinks of carbon dioxide must be determined. During FY 99, the
PMEL CO2 group determined the distribution of pCO2 in the equatorial Pacific during the transition between the 1997-98 El Niño and
the 1998-99 La Niña event. Data from the eastern equatorial Pacific during and after the 1997-98 El Niño shows that, during the mature
phase of the1997-98 El Niño, surface-water pCO2 was generally below atmospheric levels (Figure 1). By June of 1998 recovery from
the El Niño had begun, and high surface-water pCO2 was measured at 0E, 155EW. The recovery at the mooring at 2ES, 170EW occurred
later; waters low in pCO2 were found at this site in June 1998. Levels increased rapidly in July, followed by large excursions associated
with the passage of tropical instability waves.
CFC Tracer and Large-Scale Ocean Circulation Program
Accomplishments in FY 99
The PMEL Chlorofluorocarbon CFC Tracer Program studies ocean circulation
and mixing processes
by measuring the distribution of dissolved CFCs in
the ocean. Key long-term goals are to document the entry of CFCs
from the atmosphere into the world ocean by means of repeat long-line
hydrographic sections at decadal intervals, and to use these
observations
to help test and evaluate ocean-atmosphere models. Comparisons
of CFC data from repeat sections highlight regions, such as the North
Atlantic
between 1988 and 1993, where intermediate and deep waters can rapidly
take
up anthropogenic gases such as carbon dioxide on decadal time-scales.
The development and testing of models models is critical for
understanding
the present state of the ocean-atmosphere system, quantifying the
ocean's
role in the uptake of climatically important trace gases such as Carbon
Dioxide, and improving predictions of climate change for the coming
century.
During FY 99, the PMEL CFC Tracer Group continued work on improving
techniques for analyzing CFCs, and techniques of storing seawater
samples
in glass ampules.
The CFC group worked on the analyses of data collected on a
multi-institutional
oceanographic
expedition in the southwestern Pacific on the NOAA Ship Discoverer
(CGC96),
as part of the World Ocean
Circulation
Experiment (WOCE) and on a long
zonal section in the North Atlantic. A variety of physical, chemical
and biological measurements were made on these expeditions. The CFC data
obtained on these expeditions highlight the rapid uptake of atmospheric
gases into these regions, and the CFC signals carried equatorward in
abyssal
currents of North Atlantic Deep Water, and Antarctic Bottom Water.
The seventh year of a NOAA supported program
study
to monitor variability of dense water formation and ventilation
processes
in the Greenland-Iceland-Norwegian Seas, using CFCs and
helium/tritium
as tracers was completed. These studies have shown that the rate of
formation
of new Greenland Sea Deep Water (GSDW) during the 1980s and early 1990s
was drastically lower than that in the 1970s. The near-cessation of the
production of this cold, dense water mass by deep convective processes
may be the result of decadal-scale changes in surface conditions in the
central Greenland Sea.
Collaborative efforts
to utilize the CFC datasets in numerical models of ocean circulation
were expanded to include groups involved in the use of CFCs and other
tracers
to evaluate models of oceanic uptake of anthropogenic Carbon Dioxide, as
part of the
OACES and
Ocean Carbon Modeling
Intercomparison Programs. Such comparison studies are critical if we
are to have confidence in the ability of such models to predict possible
changes in the earth's climate due to release of greenhouse gases or
other
anthropogenic activities.
Monitoring Transport of Ocean Currents
Accomplishments in FY 99
Daily mean values of the Florida Current volume transport have been
measured since 1982 from cross stream voltages using a retired
submarine telephone cable from 1982 to 1990 and an in-service cable
from 1990 to 1999 when it was retired. The data set is nearly
continuous and has been calibrated using profiling derived transports.
The decadal transport variations (excluding periods less than two years)
from 17 years of daily mean values converted to montly mean values, show
a strong correlation (0.92) with the negative value of the North
Atlantic Oscillation when the transport is lagged by 10 months. In other words,
the Florida Current transport increases when the westerlies decrease.
This high correlation reveals a strong decadal connection between the
NAO, a purely atmospheric climate indicator, and the purely
oceanographic measurement of the Florida Current. Importantly, it would not have
been possible to detect this decadal variation with shorter time
series.
Fisheries Oceanography Coordinated Investigation
Accomplishments in FY 99
During FY 1999, Fisheries-Oceanography
Coordinated Investigations (FOCI) led nine research
cruises, and participated in five others, for a total of 225 sea days,
to the North Pacific, Gulf of Alaska, and Bering Sea during spring, summer,
and fall. Activities included deployment and recovery of moorings
and biophysical platforms, surveys of marine life, measurement of water
properties, and studies of processes that affect the ecosystem. In
spring, a cruise to the eastern Bering Sea surveyed mesopelagic
fishes and squids, a little-studied component of the ecosystem.
During summer and fall, FOCI again documented a bloom of coccolithophorid
phytoplankton concurrent with the coldest water temperatures seen on the
shelf in the last five years. Information from FOCI's field operations
may be instrumental in explaining why these events happened.
FOCI scientists convened an International
Workshop on Recent Conditions in the Bering Sea. The purpose of the
workshop was to share information, integrate knowledge, suggest mechanisms,
propose hypotheses, and outline future research needs to address and understand
changing conditions in the Bering Sea. A prominent theme of the workshop
was the implication of recent environmental changes on the management of
living marine resources. Workshop participants agreed that focused,
long-term, integrated research is needed, and recommended the recently
written Draft Science
Plan for the Bering Sea Ecosystem (pdf file requires Adobe
Acrobat Reader) that FOCI helped craft last year.
Southeast Bering Sea Carrying
Capacity (SEBSCC) began its second research cycle (1999-2000) for NOAA's
Coastal Ocean Program. Objectives are to (1) determine how changes
in on-shelf transport of nutrients impact pelagic food webs (including
determination of how timing, duration, magnitude and species composition
of primary, secondary and forage fish production affect food availability
for higher trophic levels), and (2) determine how climate variability influences
the spatial overlap of pollock of different life stages, and how the availability
of juvenile pollock to predators affects pollock survival rate. First-year
results underscore the importance of sea ice to ecosystem variability
and establish some environmental factors that may be used to develop an
index of pollock survival. A final
report (pdf file) on the first SEBSCC research cycle (1996-1998) supports
the need to continue monitoring of the productive southeastern Bering Sea
shelf to better understand the response of the ecosystem to climate forcing.
Contrasts in the environment of the Bering Sea shelf and slope from observations
made during 1996, 1997, and 1998 underscore the strong interannual variability
in the ecosystem. Seasonal pack ice extent and duration, wind-driven
mixing over the shelf during spring and summer, summertime sea surface
temperature, mixed layer depth, timing of the spring phytoplankton bloom,
summer nutrient reservoir concentrations, seabird mortality, and salmon
returns varied widely during the first research cycle. One hypothesis
is that oceanographic conditions, and, to a degree, biological responses,
are controlled by climate/weather fluctuations. For example, the
position and strength of the Aleutian Low affects the direction and intensity
of winds over the Bering Sea. Those winds largely control the duration
and extent of seasonal pack ice which influence the cold pool, a persistent
area of cold, sub-surface water. These features, in turn, affect
the timing of the spring bloom and cannibalism of juvenile pollock by adults.
FOCI, one of a few marine fisheries oceanography programs in the world
predicting recruitment, made its eighth annual prediction
of pollock year-class strength for Shelikof Strait: average recruitment
for the 1998 year class. Developed in 1992, the Shelikof Recruitment Index
(SRI) is based on process-oriented studies, field surveys, and numerical
modeling experiments. This index is used to predict the abundance
of age-0 and age-1 walleye pollock that will survive to recruit to the
Shelikof Strait, Gulf of Alaska, fishery as adults. SRI incorporates
environmental estimates such as rainfall, wind mixing, advection, and larval
abundance, and predictions by SRI compare favorably with actual recruitment.
Together with spawning biomass estimates also produced by FOCI, the index
provides fishery-independent
information that helps National Marine Fisheries Service stock assessment
scientists project future stock sizes. These projections help the
North Pacific Fishery Management Council establish fishing quotas
for the Gulf of Alaska. This year FOCI began cooperative work with
NMFS stock assessement specialists to incorporate FOCI's predictive scheme
into the stock assessment model.
FOCI also supported the Bering
Sea and North Pacific Ocean Theme Page, a clearing house for regional
environmental information. The theme page provides pointers to information
and images generated by NOAA, universities and other governmental sources.
Included are links to up-to-date satellite imagery, new research, and educational
material related to the North Pacific Ocean and the Bering Sea. The
theme page also links to historical and real-time data, and to the Bering
Sea Ecosystem Biophysical Metadatabase, a resource for locating data
pertaining to the Bering Sea ecosystem.
Vents Program
Accomplishments in FY 99
The second annual expedition to the NeMO (New Millenium Observatory)
site in the vicinity of Axial Volcano was conducted in June and July,
1999 from the R/V’s Thomas G. Thompson and
Wecoma. Twenty-one dives were
made this year at NeMO in the area of Axial Volcano with the Canadian
ROV ROPOS. While the Axial Volcano continued in a post-eruptive phase
following the eruptive activity of January, 1998, many interesting
investigations continue at the site. Among them were:
- The discovery of several previously unknown hydrothermal vents south
of Axial caldera in a new lava flow.
- High-resolution sea-floor mapping in the northern portion of the new
lava flow using the Imagenex sonar system mounted on ROPOS
- An array of seafloor miniature temperature recorders (SMTRs) was
deployed near several seafloor vents in the Axial caldera to monitor
trends in individual vent temperatures, to correlate temperature
changes with geophysical events, if possible, and to compare seafloor
temperature changes to changes observed in the water column by annual
ship surveys and in situ temperature recording moorings to assess the
impact of hydrothermal fluxes from the Axial Volcano.
- Using ROPOS, engineers freed from the new lava the Volcanic Systems
Monitor that that had been embedded in lava following the January, 1998
eruption.
- For the first time, images and data from a remote seafloor-mounted
camera and array of temperature sensors were transmitted in
near-realtime via acoustic telemetry and satellite to the laboratory.
- 1999 marked the second year (and third cruise) of monitoring
hydrothermal changes resulting from the 1998 eruption on Axial Volcano.
A series of CTD tows and casts found that the inventory of hydrothermal
heat and particulate matter in the water column over Axial continued to
decline. The decrease of both species can be modeled as a power law,
with the rate of decline similar to that observed at CoAxial following
the 1993 eruption.
- Between the 1998 and 1999 field seasons, Vents scientists improved on
the prototype hydrothermal fluid and particle sampler (HFPS) and then
used it to collect 120 samples during 5 ROPOS dives at Axial Volcano. A
major emphasis of the NEMO project is the investigation of the
sub-seafloor microbial biotope, and the HFPS is the primary tool to
recover samples. 1999 was our second year of studying the hydrothermal
effects of the January, 1998, volcanic eruption. The time series and
spatial extent of our diffuse vent fluid sampling in the eruption area
are unprecedented, and we are gaining new insight to the chemical and
microbiological importance of low-temperature reaction particle samples
was characterized and revealed very high diversity in both
particle-attached and "free-living" microbes.
- The Cleft segment time series plume chemistry studies continued in
1999. Total CO2 measurements were added to the suite of analytes, to
provide background values for future eruptive events in this area.
- The Axial Volcano post eruption monitoring continued in 1999 as well.
Significant decreases from 1998 were observed in CO2, Fe, and Mn.
- The primary objective of the VENTS Suspended Matter Project is to
provide a better understanding of the evolution of particulate
hydrothermal chemical species, including S and Fe, near deep-sea vents.
These chemical species provide the metabolic energy resources for
hydrothermal particle-bound bacteria, and the resulting vent-related
ecosystems. Towards this end, we are focussing on hydrothermal sources
and sinks for particulate sulfur. We have developed a procedure for
collection, preservation and analysis of particulate non-volatile and
volatile sulfur by x-ray fluorescence spectrometry. Coupled with our SEM
methods, these procedures help us to differentiate between biotic and
abiotic forms of sulfur (Figure 1). We are working closely with the
microbiologists at UW and WWU to identify particle-bound bacteria.
Together with the micobiological results, we will elucidate the
efficiency of the microbial systems with respect to the chemical species
emanating from deep-sea vents.
Other major activities and accomplishments included:
- Autonomous hydrophones were deployed in the North Atlantic to monitor
seismic activity in the mid-Atlantic Ridge. Another array of hydrophones
was deployed in the North Pacific and Gulf of Alaska to aid in studying
the behavior of marine mammals in that region.
- Thermistor and current measurements at Axial Volcano were used in a
inverse calculation to infer active-vent locations that might have been
overlooked by sea floor towed-instrument surveys. Results suggest,
among other things, the likelihood of hydrothermal sources on the
eastern flank of the volcano during 1998, but ones which ceased
discharging by summer 1999.
- Numerical experiments of buoyant convection from line segment sources
were undertaken for both laboratory and ocean scalings to examine the
number of individual bolues into which rising event plumes might break.
At ocean rotation rates and stratification, breakup is borderline.
Results suggest an event plume source must be actively discharging along
more than several kilometers of seafloor before even two plumes at the
level of neutral buoyancy could be created.
- Publication of a paper in Earth Planetary Science Letters addressing
the way in which event plumes, or megaplumes, are produced during
magmatic events on mid-ocean ridges. This paper relied on the helium
and heat content in these event plumes to place constraints on the
mechanism of their formation.
- Completion of a major expedition exploring hydrothermal vent sites
along the southern East Pacific Rise using the deep submersible Alvin.
Tsunami Program
Accomplishments in FY 99
The PMEL Tsunami Program seeks to mitigate tsunami hazards in Hawaii,
California, Oregon, Washington, and Alaska through research and
development aimed at improving operational products. The Program
conducts instrumental, observational, and modeling R&D through three
tightly coupled activities: the Deep-ocean Assessment and Reporting of
Tsunamis (DART) Project; the Center for Tsunami Inundation Mapping
Efforts (TIME); the Short-term Inundation Forecasting for Tsunamis
(SIFT) Project. Research efforts focus on improved understanding of
tsunami generation, propagation and inundation dynamics; development
efforts focus on providing the nation with effective tools for tsunami
hazard mitigation, including real-time reporting measurement systems,
improved inundation maps for at-risk communities, and an integrated
event- and site-specific forecasting capability.
NOAA bears primary national responsibility for tsunami warning and
hazard mitigation and is the lead agency for implementation of the
U.S. National Tsunami Hazard Mitigation Program (NTHMP). The PMEL
Tsunami Program continues to coordinate the activities of the three
Federal agencies and five States that are members of the NTHMP.
This includes hosting and
participating in NTHMP Steering Group meetings and the development of
informational Web sites and electronic bulletin boards. In FY 99,
DART and TIME support was augmented by the NTHMP.
The DART Project successfully deployed three systems in the North
Pacific, establishing two stations just south of the Alaskan-Aleutian
Seismic Zone (AASZ), a known region of tsunamigenic potential. A
third DART station was maintained off California as an engineering
test site. All systems survived the hostile North Pacific winter
season, and improvements to the communications system successfully
increased the data return rate to acceptable levels. The real-time
DART data stream is now accessed by NOAA's Pacific Tsunami Warning
Center (PTWC) and the West Coast and Alaska Tsunami Warning Center
(WCATWC), and can be viewed at the DART Data Quality Control web site.
The TIME Center continued to provide valuable assistance to the NTHMP States in the
development of inundation maps for at-risk communities. In Oregon,
inundation maps have been produced for the communities of Warrenton
and Astoria, and a risk analysis has identified and prioritized an
additional seven communities to be mapped. In Washington, two maps
have been completed that cover all at-risk communities on the soutwest
coast in Gray's Harbor and Pacific Counties. In California, TIME
developed merged bathymetric/topographic grids essential to the
numerical modeling of the San Francisco, Santa Barbara, Los
Angeles/Long Beach and San Diego areas; modeling of these coastal
regions is now underway. In Alaska, inundation modeling was initiated
for three study areas -- the City of Kodiak, the U.S. Coast Guard Base
region, and Women's Bay -- using merged bathy/topo grids developed by
TIME; fifteen additional high-priority communities have been
identified for future mapping. Hawaii inundation modeling activities
were begun in FY 99 through a competitive selection process that
awarded two tsunami modeling contracts -- one to address the issue of
distant tsunami generation, the other to investigate locally generated
events.
The SIFT Project published three reports, the first on tsunami
prediction in coastal regions and a forecast method to predict the
heights of later waves, the second on an analytic theory for tsunami
wave scattering in the open ocean, the third on forecasting offshore
Hawaii tsunamis and the creation of a database of model runs
simulating multiple scenarios of tsunami generation in the AASZ and
propagation into deep water off Hawaii
The
generation/propagation database was also transferred to the Pacific
Disaster Center as the first step in developing a real-time,
site-specific, Hawaii inundation forecasting capability to guide
decision-making during an actual event.
Innovative Technology
Innovative technology in software and hardware has been developed in support of
PMEL's research projects. Outstanding software and data management capabilities
allow scientists to access, view and analyze observational
and gridded data,
and to work with geograpical
information systems. Up-to-date information about PMEL
research is available on the World Wide Web, and near-realtime data, analysis
products and retrospective climatologies can be previewed
and downloaded for further analysis.
Three dimensional visualizations, animations,
and Virtual Reality methodologies
enable scientists to view and interact with data in new ways.
Perspective on PMEL's research program results is provided by
World Wide Web Theme Pages.
Essential support for computer and network technology are provided
by PMEL's Computing and
Network Services Division.
PMEL's Engineering Development
Division supports PMEL research with innovations in elecronics, mechanics,
materials, and sofware engineering. PMEL's
measurement capabilities in the field and laboratory are enhanced by application
of state-of-the-art instruments and systems that integrate observational and
measurement technologies.
University/NOAA Partnerships
NOAA has established formal collaborative research
agreements with
participating
universities to form the Joint Institutes. The Joint Institutes
combine the resources of universities and NOAA to develop centers
of excellence in environmental research.
PMEL complements its research efforts through four cooperative
institutes: the Joint Institute for Study of the Atmosphere and Ocean
(JISAO), with the University of Washington;
the Joint Institute for Marine and Atmospheric Research (JIMAR), with the University of Hawaii;
Cooperative Institute for Arctic Research (CIFAR), with the University of
Alaska; and the Cooperative
Institute for Marine Resources Studies (CIMRS), with
Oregon State University.
Tropical Atmosphere-Oceans Program
Plans for FY 00
-
Maintain the array as part of the ENSO Observing System in
support of NOAA's Seasonal to Interannual Climate Prediction Program (SICPP),
GOOS, GCOS, and CLIVAR.
-
Transition the TAO array to the TAO/TRITON array, with TRITON
moorings maintained by the Japan Science and Technology Center (JAMSTEC) west of
165E.
-
Continue transition to Next Generation ATLAS moorings east of
165E; upgrade ATLAS moorings for real-time velocity, longwave radiation, and
barometric pressure.
-
Continue moored radiation, rainfall, bio-optical, chemical, and
salinity measurements as part of collaborative studies.
-
Expand and enhance the array in the eastern tropical Pacific
along 95W in support of NOAA's Pan American Climate Studies (PACS)/Eastern
Pacific Investigation of Climate Processes (EPIC).
-
Conduct a special month-long land-based intercomparison study
between ATLAS, TRITON, and WHOI/IMET moorings at Woods Hole Oceanographic
Institute.
-
Complete the PIRATA array in the tropical Atlantic (12 sites);
expand and enhance PIRATA with new moorings in "hurricane alley" (10-20N).
-
Conclude NOPP field program with recovery of moorings at
Stations PAPA and MOMMA.
-
Maintain and enhance on-line access to TAO data sets.
-
Continue scientific analyses of TAO, PIRATA, and NOPP data, in
conjunction with shipboard, satellite, historical, and model based
data sets.
Thermal Modeling and Analysis Project
Plans for FY 00
Continue study of atmospheric subseasonal variability and its
effects on ENSO. Composite the ocean surface expression of the
MJO during periods when NINO3 SSTA is cooler than normal, normal
and warmer than normal. Evaluate the OLR signatures of WWEs and
contrast with those of the MJO. Composite the cold tongue SST
changes following WWEs, according to whether or not the WWE was
part of an MJO. Examine the effects of MJO forcing on the
tropical Indian and Atlantic oceans.
Compare the ENSO Cold and Warm event composites, in the
context of EOF and regression "S-I" modal patterns, simple models
of SST-wind anomaly relationships, and simple coupled models of
ENSO.
Examine the utility of regression modes for Pacific decadal
variability of SST and wind and wind speed. Examine the US
seasonal weather associations relative to a North Pacific SSTA
index
that is in the core PDO region.
Work with NCEP and NRL/MRY to try to improve the impact of
ocean surface wind observations on operational surface wind
products.
Work with NCEP, OSU and FNMOC toward a new ocean data
assimilation system for NCEP, using the MOM-4 model.
Atomspheric Chemistry Program
Plans for FY 00
- Finish Aerosol99/INDOEX data analysis and prepare manuscripts for publication in the JGR Special Sections.
- Continue long-term monitoring of aerosol chemical composition at the NOAA Aerosol Regional Monitoring Network of stations at Barrow, AK, Bondville, IL, and Southern Great Plains, OK.
- Continue the organization of ACE Asia planned for March/April 2001
Carbon Dioxide Program
Plans for FY 00
In the 1990s, the cooperative multi-agency efforts of the World Ocean Circulation Experiment (WOCE), Joint Global Ocean Flux Study
(JGOFS), and Ocean-Atmosphere Carbon Exchange Study (OACES) together with parallel international programs greatly improved the
global ocean carbon database. Total carbon dioxide (TCO2) data sets accurate to 2-3 µmol/kg, equivalent to approximately 2 to 3 years’
uptake of anthropogenic CO2 in near-surface waters, are now available for hydrographic transects representing most of the world’s oceans.
These data, together with recently improved interpretive techniques, will allow a comprehensive global estimate of anthropogenic CO2 in the
oceans that will serve as a bench mark for future observational programs. The spatial distribution of the data-based inventory estimates also
provide robust constraints for the evaluation of prognostic ocean carbon models. Figure 1. Zonal mean anthropogenic CO2 column inventories.
Atlantic results from Gruber (1998), Indian results from Sabine et al. (1999), Pacific results based on preliminary estimates along P16 (155ºW) only.
The preliminary results are shown in Figure 2 as zonal means of the anthropogenic CO2 column inventories. This figure clearly shows the
large North Atlantic sink for CO2 as well as substantial sinks in the Southern Hemisphere associated with the Subtropical Convergence
in both the Atlantic and Indian Oceans. These calculations imply that relatively little anthropogenic CO2 is stored in the high latitude
Southern Ocean. Analysis of the Pacific data is currently underway. A first look at the meridional trends in the Pacific can be estimated from
the preliminary column inventory estimates along WOCE line P16 (~155°W). The location of the largest inventories in all three basins are
generally consistent with the location of the largest net surface ocean CO2 sink regions as compiled by Takahashi et al. (1999). During
FY 2000, the Global Carbon Cycle Program will continue the analysis of the field data from the Atlantic, Pacific and Indian Oceans.
In particular, the group will compare data sets obtained on other WOCE-WHP cruises and will provide internally consistent data sets
encompassing roughly 16 cruises in the Pacific Ocean, 15 cruises in the Indian Ocean, and 10 cruises in the Atlantic. These data
will be used by the modeling community for setting boundary conditions for general ocean circulation models, to determine the DIC
inventory in each basin using several independent methods, and to estimate anthropogenic CO2 increases in the ocean. To facilitate
comparisons of models and observations, the data will be gridded into similar box sizes as currently used in the models.
In addition to this activity, we will continue our pCO2 instrument development activities with the group at MBARI, directed by Francisco
Chavez, to provide a suite of chemical and biological sensors deployed on the 155EW and 170EW TAO morring array in the equatorial
Pacific. The work leverages on developmental efforts carried out by MBARI (with support from NOAA, NASA, and PMEL) over the
past several years. The primary objectives of this project are: (1) to determine the relationships between physical forcing, primary
production and the exchange of carbon dioxide between ocean and atmosphere; (2) to determine the biological and chemical responses
to climatic and ocean variability in the equatorial Pacific; (3) to determine the spatial, seasonal and interannual variability in primary
production, carbon dioxide, and nutrient distributions; and (4) to determine the spatial, seasonal and interannual variability of sea surface
pigment distributions to groundtruth sattelite measurements of ocean color.
CFC Tracer and Large-Scale Ocean Circulation Program
Plans for FY 00
-
Improve analytical techniques for measuring CFCs in the atmosphere and
ocean.
-
Develop improved techniques for the long-term storage of dissolved CFC
samples.
-
Continue the program to monitor annual variability of dense water
formation
and ventilation process in the Greenland-Iceland-Norwegian Seas, using
CFCs and helium/tritium as tracers.
-
Complete analyses of data collected on the NA24N expedition.
-
Take the lead on the synthesis of the CFC data collected as part of the
WOCE Hydrographic Progam
Pacific One-Time Survey,
in collaboration with other investigators.
-
Work jointly with other investigators on a global synthesis of the WOCE
CFC data sets.
-
Continue interactions with modelers and utilize the CFC results to help
evaluate and improve the ability of numerical models to realistically
simulate
oceanic ventilation processes as well as carbon uptake and
transport.
Monitoring Transport of Ocean Currents
Plans for FY 00
The in-service cable has been retired and permission has been
granted by AT&T and Batelco to record voltages at the Eight Mile
Rock site, Grand Bahama Island, using the retired cable. The
voltage measurements will resume in March 2000.
The observation program will continue with a strong collaboration
between AOML and PMEL/JIASAO. AOML will maintain the cable voltage
and calibration measurements and PMEL/JIASAO will play an advisory role
until the measurement program and data reduction software is fully in
place. PMEL/JIASAO will then continue collaboration on the interpretion
of the transport measurements.
PMEL/JIASAO plans to explore ways to continue a network of existing
trans-Pacific cable measurements for montinoring ocean currents.
Measurements have been made for several years by other groups. Results
indicate a highly suggestive similarity between Hawaii-to-California
voltages and variations in the strength of large scale atmospheric
patterns related to the strength of the Aleutian Low. Climate signals
on the time scales suggested will take at least another decade of data
to begin to resolve.
Fisheries Oceanography Coordinated Investigation
Plans for FY 00
-
Continue monitoring marine environmental conditions on the Bering Sea shelf
to help understand climate- to local-scale processes affecting the ecosystem.
Data from moorings at one of the proposed sites are the longest continuous
time series of oceanographic variables measured for the Bering Sea.
-
Conduct winter, spring and fall research
cruises to the North Pacific, Gulf of Alaska, and Bering Sea supporting
physical, biological and biophysical research for FOCI, SEBSCC, Arctic
Research Initiative, North Pacific Marine Research Program and other associated
programs.
-
Produce a special
issue of Topical Studies in Oceanography on the eastern Bering
Sea ecosystem, with core articles by FOCI researchers.
-
Forecast recruitment of the 2000 walleye pollock year class for Shelikof
Strait.
Vents Program
Plans for FY 00
- Vents scientists remain ready to respond to volcanic events along the
northeast Pacific seafloor spreading centers as determined by seismic
monitoring utilizing the SOSUS array. Scientists will study the
physical, thermal, and chemical characteristics of hydrothermal plumes
resulting from the volcanic activity as well as hydrothermal fluids
venting on the seafloor. A major goal of the event response is to survey
and sample microorganisms which are now known to be venting from new
eruption sites.
- The third annual expedition to the NeMO site will take place in
July-August 2000 aboard the NOAA Ship Ronald H. Brown. Activities will
include deployment of geophysical and hydrothermal instrument systems,
sampling and mapping of geochemical, suspended matter, and water column
properties, and continued geological mapping of the Axial eruption site.
An enhanced monitoring capability will be deployed at Axial, providing
continued sampling of the seafloor environment and near realtime
delivery of collected data to the laboratory.
- Forces that drive steady and subtidal flows at ridge crest depth are
incompletely understood. Measurements often show ridge crest currents
have component periods of ~ five days, suggesting meteorological influence.
One possible connection between surface and seafloor is through
pressure. Numerical experiments will be used to study whether five-day
pressure gradient signals might occur at the sea floor as the result of
incomplete compensation of atmospheric loading by sea surface elevation.
- A cruise to collect additional bathymetric survey data of the Juan de
Fuca Ridge will be accomplished in March.
- Analysis of samples and data collected during the Alvin dives along
the southern East Pacific Rise will be undertaken. We will also
continue to work on samples and data collected with ROPOS dives on the
Juan de Fuca Ridge. A paper describing the distribution of hydrothermal
venting in the pull-apart basins along the Blanco Transform system is
also in preparation.
- As a part of the NeMO cruise activities in July-August, 2000, 15-30
temperature sensors will be deployed directly on the seafloor. These
sensors will be used to monitor long term variations in the temperature
of hydrothermal fluids, variations that may be related to future
tectonic or volcanic activity.
- In FY 2000 the Vents Suspended Matter Project will determine the
relationships between the magnitude of the hydrothermal emission signals
at Axial Volcano and the regional distribution and temporal variability
of particulate inside and beyond Axial Summit Caldera. Our research is
designed to provide quantitative information on the effects of
hydrothermal venting and microbial processes on the chemistry of the
water column of the Pacific Ocean. We intend to deploy an in-situ
particle sampling system to collect co-located plume samples of vent
bacteria and the concentrations particulate Fe, Mn and S, and
particulate trace metals within a hydrothermal plume. We envision short
term-deployments near the vents for the periods of about 4-5 days to
understand high-frequency variability, and also year-long deployments to
obtain information on the longer time scales of variability. This
research has an excellent potential for a strong Vents Chemistry
collaboration with the microbiological efforts of our colleagues at UW,
WWU and the University of Hawaii.
- In 2000, vent fluid chemistry results from the first two years of
sampling at NeMO will be published. We are working on joint
publications with U.W. microbiologist John Baross. We will continue the
time series sampling work at Axial Volcano during ROPOS operations on
the Ron Brown using the hydrothermal fluid and particle sampler (HFPS).
- The HFPS will also be used during an Alvin/Jason submersible research
program to study the effects of tidal perturbations on hydrothermal
systems on the Endeavour segment of the Juan de Fuca ridge.
- In FY 2000, work will be undertaken to initiate a volcanic response
system based on the use of new technology which will allow moorings and
other instrumentation to be deployed from commercial and or military
aircraft. When fully implemented this program will allow an air response
to submarine volcanic eruptions within 24 to 36 hours of their
occurrence as opposed to our current 7-10 day response time using
research ships.
Tsunami Program
Plans for FY 00
- Continue to coordinate the three agencies and five states
participating in the NTHMP.
- Continue the development of real-time DART systems. Maintain
and expand the current network to three sites in the Gulf of Alaska
and one off the U.S. West Coast.
- Continue to assist Hawaii, California, Oregon, Washington and
Alaska in the production of tsunami inundation maps for threatened
coastal communities.
- Develop an inundation forecasting database for Hilo and
Kahului, Hawaii.
Go to
PMEL FY 99 Programs and FY 00 Plans
)window.location='http://www.pmel.noaa.gov/accomp/aerosolexp3.gif'){kind=link}