BOREAS AFM-03 NCAR Electra 1994 Aircraft Sounding Data Summary The BOREAS AFM-03 team used the NCAR Electra aircraft to make sounding measurements to study the planetary boundary layer using in situ and remote- sensing measurements. Measurements were made of wind speed and direction, air pressure and temperature, potential temperature, dewpoint, mixing ratio of H2O, CO2 concentration, and ozone concentration. Twenty-five research missions were flown over the NSA, SSA, and the transect during BOREAS IFCs 1, 2, and 3 during 1994. All missions had from 4 to 10 soundings through the top of the planetary boundary layer. This sounding data set contains all of the in situ vertical profiles through the boundary layer top that were made (with the exception of "porpoise" maneuvers). Data were recorded in 1-second time intervals. These data are stored in tabular ASCII files. Table of Contents * 1 Data Set Overview * 2 Investigator(s) * 3 Theory of Measurements * 4 Equipment * 5 Data Acquisition Methods * 6 Observations * 7 Data Description * 8 Data Organization * 9 Data Manipulations * 10 Errors * 11 Notes * 12 Application of the Data Set * 13 Future Modifications and Plans * 14 Software * 15 Data Access * 16 Output Products and Availability * 17 References * 18 Glossary of Terms * 19 List of Acronyms * 20 Document Information 1. Data Set Overview 1.1 Data Set Identification BOREAS AFM-03 NCAR Electra 1994 Aircraft Sounding Data 1.2 Data Set Introduction The BOReal Ecosystem-Atmosphere Study (BOREAS) Airborne Fluxes and Meteorology (AFM)-03 team used the National Center for Atmospheric Research (NCAR) Electra aircraft to make sounding measurements to study the planetary boundary layer using in situ and remote-sensing measurements. Measurements were made of wind speed and direction, air pressure and temperature, potential temperature, dewpoint, mixing ratio of H2O, CO2 concentration, and ozone concentration. Twenty-five research missions were flown over the Northern Study Area (NSA), Southern Study Area (SSA), and the transect during BOREAS Intensive Field Campaigns (IFCs) 1, 2, and 3 during 1994. All missions had from 4 to 10 soundings through the top of the planetary boundary layer. This sounding data set contains all of the in situ vertical profiles through the boundary layer top that were made (with the exception of "porpoise" maneuvers). Data were recorded in 1-second time intervals. These data are stored in tabular American Standard Code for Information Interchange (ASCII) files. 1.3 Objective/Purpose The Electra aircraft was used both to measure surface fluxes and to study the planetary boundary layer using in situ and remote-sensing measurements. This sounding data set contains all of the in situ vertical profiles through the boundary layer top that were made (with the exception of "porpoise" maneuvers). 1.4 Summary of Parameters The AFM-03 soundings data include time, date, location, wind speed and direction, air pressure and temperature, potential temperature, dewpoint, mixing ratio of H2O, CO2 concentration, and ozone concentration. 1.5 Discussion A total of 25 research missions were flown, distributed fairly evenly throughout IFCs 1, 2, and 3. Flights were always along the regional transect, following the waypoints between Saskatoon and Churchill, except for some deviations north of the NSA. See Section 7.1 for location of the waypoints. Some missions concentrated exclusively on the SSA (waypoints A-H). Other missions (at least one each IFC) went to/from Churchill, Manitoba (YYQ). All missions had from 4 to 10 soundings through the top of the planetary boundary layer. Takeoff and landing vertical profiles (at Saskatoon (YXE) or Churchill (YYQ)) are included when they penetrated the top of the boundary layer. Most soundings were transitions between legs flown at 100 meters above ground level (AGL) to measure fluxes close to the surface and legs flown above the boundary layer (sometimes as high as 3,150 meters AGL) to measure continuous water vapor profiles remotely using a downward-looking water vapor DIAL instrument. These soundings were flown as circles near the waypoint so that both the low and high legs would begin/end at the same location. There are several flights, such as R05, where a very long (in this case 1,000 km) flight at 100 meters was broken up by an "up- and-down" sounding. All flights had other changes of altitude within the boundary layer that have not been included in this data set. 1.6 Related Data Sets BOREAS AFM-01 NOAA/ATDD Long-EZ 1994 Aircraft Flux Data over the SSA BOREAS AFM-02 Wyoming King Air 1994 Aircraft Flux and Moving Window Data BOREAS AFM-03 NCAR Electra 1994 Aircraft Flux Data BOREAS AFM-03 NCAR Electra 1994 Aircraft Moving Window Data BOREAS AFM-04 NRC Twin Otter Aircraft Flux Data BOREAS AFM-04 NRC Twin Otter Aircraft Sounding Data BOREAS AFM-05 Level-1 Upper Air Network Data BOREAS AFM-05 Level-2 Upper Air Network Standard Pressure Level Data 2. Investigator(s) 2.1 Investigator(s) Name and Title Donald H. Lenschow National Center for Atmospheric Research/MMM Boulder, CO (303) 497-8903 (303) 497-8181 (fax) 2.2 Title of Investigation Airborne Investigation of Biosphere—Atmosphere Interactions Over the Boreal Forest 2.3 Contact Information Contact 1 ---------- Donald H. Lenschow NCAR/MMM Boulder, CO (303) 497-8903 (303) 497-8181 (fax) lenschow@ncar.ucar.edu Contact 2 ---------- Steven P. Oncley NCAR/ATD/SSSF Boulder, CO (303) 497-8757 (303) 497-8770 (fax) oncley@ucar.edu Contact 3 ---------- Jeffrey A. Newcomer Raytheon ITSS NASA GSFC Greenbelt, MD (301) 286-7858 (301) 286-0239 (fax) 3. Theory of Measurements This section summarizes the capabilities of the Electra as used in BOREAS. For a complete description, see the Project Summary Documentation for BOREAS distributed by the Research Aviation Facility (RAF) and associated RAF Bulletins. Winds were determined by combining measurements of the air motion relative to the aircraft by pressure sensors connected to five holes on the radome of the Electra, with aircraft motion measured by a Honeywell laser inertial reference system (IRS). Corrections to the IRS data were made using measurements by a Global Positioning System (GPS) satellite receiver. See NCAR RAF Bulletin No. 23 for a complete description of this system and the data processing used. In situ measurements of temperature, humidity, atmospheric pressure, aerosol and cloud droplet size distributions were made by sensors mounted to the wing and fuselage of the aircraft (RAF Bulletin Nos. 22 and 24). In situ measurements of chemical constituents were made by drawing outside air into closed-path sensors within the aircraft cabin. These sensors included a LI-COR LI-6262 for water vapor and carbon dioxide and two NCAR gas-phase chemiluminescent sensors for ozone. 4. Equipment 4.1 Sensor/Instrument Description None given. 4.1.1 Collection Environment Most data were acquired by an onboard computer that handled serial digital data, analog data (after anti-alias filtering), and event counters. (The DIAL system and disjunct sampler each had independent data systems.) Data were written to 8-mm digital tape in flight and were later processed using the Nimbus program to calibrate, digitally filter (when necessary), and synchronize the final time series. The time series data sets are available in NetCDF format at two data rates: 1) all channels output at 1 sample/second, and 2) all turbulence channels output at 25 samples/second. 4.1.2 Source/Platform All instruments were mounted on a Lockheed Electra, which is a pressurized, low- wing, turbo-propeller airplane, designed as a medium-range airliner. It is powered by four Allison 501-D13 constant-speed, axial-flow, turbine engines that drive four-bladed, full-feathering, reversible-pitch, turbo-propellers. Flight is approved in known icing conditions; however, external instrumentation installations may restrict operations in icing conditions. 4.1.3 Source/Platform Mission Objectives See Section 1.3. 4.1.4 Key Variables See Sections 1.4 and 7.3. 4.1.5 Principles of Operation See Section 4 and associated documents. 4.1.6 Sensor/Instrument Measurement Geometry Most turbulence sensors are mounted on or near the aircraft radome on the fuselage. The air-chemistry instruments had sampling inlets protruding from window locations along the fuselage. Particle size sensors were mounted from pylons on the wings. 4.1.7 Manufacturer of Sensor/Instrument None given. 4.2 Calibration Most of the sensors were calibrated following normal NCAR/RAF procedures. See the Project Documentation Summary for BOREAS (in particular, the Data Quality Report), available from Paul Spyers-Duran, for a complete description of the data used for these calibrations and a list of unique problems. Some general conclusions: Wind finding was good once a 10- to 15-degree bias in wind direction was removed. Aircraft position and velocity measured by the IRS were adjusted to match positions from the GPS receiver. The Lyman-alpha hygrometer failed during flights 3, 9, and 12, and during periods of flights 17 and 20. For these flights, the LI-COR measurement of humidity was used. The bottom dewpoint hygrometer performed worse than a "top" one, so the top sensor was used for all flights. The LI-COR carbon dioxide channel was calibrated using a series of measurements with calibration gases during preflight testing and in-flight. An empirical fit using pressure and temperature was used, since the manufacturer calibration equation performed poorly. 4.2.1 Specifications Specifications for standard Electra sensors are given in RAF Bulletin No. 4. 4.2.1.1 Tolerance None given. 4.2.2 Frequency of Calibration See the Project Documentation Summary for BOREAS (in particular, the Data Quality Report), available from Paul Spyers-Duran. Many sensors are checked before every flight. 4.2.3 Other Calibration Information None given. 5. Data Acquisition Methods Most data were acquired by an onboard computer that handled serial digital data, analog data (after anti-alias filtering), and event counters. (The DIAL system and disjunct sampler each had independent data systems.) Data were written to 8- mm digital tape in flight and were later processed using the Nimbus program to calibrate, digitally filter (when necessary), and synchronize the final time series. The time series data sets are available in NetCDF format at two data rates: 1) all channels output at 1 sample/second, and 2) all turbulence channels output at 25 samples/second. 6. Observations 6.1 Data Notes None given. 6.2 Field Notes Each investigator on the aircraft kept his/her own set of (usually handwritten) notes. These have not yet been assembled into a complete document. 7. Data Description 7.1 Spatial Characteristics These data were taken at 1-second intervals during aircraft vertical spiral maneuvers and during takeoff and landings. At a nominal airspeed of 100 m/s and climb rate of 10 m/s, this corresponds to measurements every 100 m horizontally and 10 m vertically. A total of 25 research missions were flown, distributed fairly evenly throughout IFCs 1, 2, and 3. Flights were always along the regional transect, following the waypoints between Saskatoon and Churchill, except for some deviations north of the NSA. This track was approximately a line from Saskatoon, Saskatchewan (52? N, 107? W) to a point north of Churchill (61? N, 95? W). The North American Datum of 1983 (NAD83) are: Waypoint Latitude Longitude A 53? 32’ N 106? 34’ W H 54? 7’ N 104? 13.5’ W K 54? 41.7’ N 103? 47.5’ W L 54? 57.3’ N 101? 58’ W M 55? 54.8’ N 99? 7.5’ W O 55? 53.2’ N 98? 00’ W P 60? 30’ N 98? 00’ W Q 60? 30’ N 95? 30’ W R 59? 00’ N 95? 30’ W CH 58? 44.5’ N 94? 04’ W Some missions concentrated exclusively on the SSA (waypoints A-H). Waypoints between A and H: Waypoint Latitude Longitudes a 53? 34.7’ N 106? 23.8’ W b 53? 42.8’ N 105? 52’ W c 53? 55’ N 105? 04’ W d 53? 59’ N 104? 47.2’ W Other missions (at least one each IFC) went to/from Churchill, Manitoba (YYQ). All missions had from 4 to 10 soundings through the top of the planetary boundary layer. Takeoff and landing vertical profiles (at Saskatoon (YXE) or Churchill (YYQ)) are included when they penetrated the top of the boundary layer. 7.1.1 Spatial Coverage All soundings are nominally taken at one point horizontally, though these usually are in the form of tight (6-km diameter) circles flown near one of the waypoints listed above. In a few cases (such as takeoffs and landings) the sounding was taken as an "enroute" climb or descent. The altitude range typically is 100 meters AGL to about 300 m above the inversion height for these soundings. Obviously, the takeoff and landing soundings go to 0 meters AGL. In some cases, the bottom of the soundings are higher. 7.1.2 Spatial Coverage Map None given. 7.1.3 Spatial Resolution Individual position measurements should be accurate to 100 m horizontally, and 1 m vertically. 7.1.4 Projection None given. 7.1.5 Grid Description None given. 7.2 Temporal Characteristics The Electra flew 25 missions during the 1994 IFCs (25-May-1994 to 16-Sep-1994): 8 in IFC-1, 8 in IFC-2, and 9 in IFC-3. 7.2.1 Temporal Coverage Each flight was about 7 hours in duration and was usually between 11:00 a.m. and 4:00 p.m. local time (all daylight hours). 7.2.2 Temporal Coverage Map Measurements were made from 25-May-1994 to 16-Sep-1994. 7.2.3 Temporal Resolution Measurements were made at intervals of 1 second. Missions were flown five to seven times per month. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (afm3as94.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (afm3as94.def). 8. Data Organization 8.1 Data Granularity All of the AFM-03 NCAR Electra 1994 Aircraft sounding Data are contained in one data set. 8.2 Data Format(s) The data files contain numerical and character fields of varying length separated by commas. The character fields are enclosed with single apostrophe marks. There are no spaces between the fields. Sample data records are shown in the companion data definition file (afm3as94.def). 9. Data Manipulations 9.1 Formulae Values are reported at one sample per second. Since all channels on the aircraft are sampled faster than this rate, these values are "boxcar" averages over all of the samples acquired during each second. 9.1.1 Derivation Techniques and Algorithms None. 9.2 Data Processing Sequence 9.2.1 Processing Steps 1. AFM-03 processed data and sent them to the BOREAS Information System (BORIS). 2. BORIS staff received the data, made necessary conversions to standard units, and loaded the data into the database. 3. BORIS staff documented the data set and compiled basic statistics about the data. 9.2.2 Processing Changes None. 9.3 Calculations None. 9.3.1 Special Corrections/Adjustments Most values reported here are copied directly from the standard RAF low-rate data file. The only exception is radar altitude, which was derived from two independent sensors. A single radar altitude was synthesized from the low-range altimeter (HGM) for altitudes less than 780 m, and from the high-range altimeter (HGME) above 780 m. This synthesized altitude had occasional spikes. These spikes were detected by testing if the difference between the pressure altitude and sum of radar altitude plus height of the ground was greater than 50 m. The ground height was set to the difference between pressure altitude and radar altitude at the first point in the sounding. Spikes were replaced by pressure altitude minus the ground height. 9.3.2 Calculated Variables Most values reported here are copied directly from the standard RAF low-rate data file. The only exception is radar altitude, which was derived from two independent sensors. A single radar altitude was synthesized from the low-range altimeter (HGM) for altitudes less than 780 m, and from the high-range altimeter (HGME) above 780 m. See Section 9.3.1 for information about corrections to this parameter. 9.4 Graphs and Plots None. 10. Errors 10.1 Sources of Error There were several instrument malfunctions during this program. See the Data Quality section of the Project Documentation Summary. Calibration gas was connected to the LI-COR CO2/H2O sensor during some flight legs. Most of these periods were near the beginning or end of a flight leg and have been removed by selection of leg start and stop times, but a few cases have been included. The LI-COR CO2 calibration is still somewhat uncertain, though it is the best we can do at this time. The Lyman-alpha hygrometer has spikes caused by rain that have not yet been removed from the data. The radar altimeter has spikes from an unknown source. These have not been removed, but should not contaminate the mean altitude much. (They should be detectable by comparing the altitude standard deviation from the radar altimeter and pressure altitude.) The dew-point hygrometer sometimes cannot keep up with large changes in temperature (as occur during ascents and descents), so humidity profiles (not included in the leg-average data) should be used with caution. 10.2 Quality Assessment Spot checks of data quality were done in the field, in calibration by NCAR/RAF, and in post-processing. These checks mostly relied on the experience of the person checking to determine if values were suspicious. Time series, profiles, and spectra have been used. According to the AFM03 team, this process is ongoing and the quality of these products is still unknown. 10.2.1 Data Validation by Source 10.2.2 Confidence Level/Accuracy Judgment None given. 10.2.3 Measurement Error for Parameters None given. 10.2.4 Additional Quality Assessments None given. 10.2.5 Data Verification by Data Center BOREAS personnel verified that the delivered data agreed with the information provided by the AFM-03 team. 11. Notes 11.1 Limitations of the Data None given. 11.2 Known Problems with the Data See the Data Quality Report (Appendix A.4) for a complete list of data quality issues. In particular, pay attention to the sections describing the following sensors: The Electra carried two dewpoint hygrometers, a Lyman-alpha hygrometer, and a LI-COR closed-path infrared absorption hygrometer. The dewpoint reported here came from the dewpoint hygrometer, which was determined to behave the best (by inspection). Even so, there are periods where this signal has large oscillations due to the inability of the hygrometer to cycle fast enough to follow the large changes in humidity often found in soundings. This behavior can be checked qualitatively by looking at the mean water vapor density, which was derived from either the Lyman-alpha or LI-COR sensor. However, both of these sensors have their own problems: the Lyman-alpha can read high after cloud penetration or rain, and the LI-COR had a pressure dependence that obviously changed with height. Also, calibrations of the LI-COR often were performed during soundings. Mean carbon dioxide (from the LI-COR) and ozone values should not be trusted due to instrument and calibration problems. Wind calculations on the Electra depend on accurate measurements of aircraft acceleration, which is large during the turns typical of these soundings. Therefore, the wind speed and direction reported here could be in error, though it is difficult assign a magnitude for this error. 11.3 Usage Guidance The Lyman-alpha hygrometer can read high after cloud penetration or rain, and the LI-COR closed-path infrared absorption hygrometer had a pressure dependence that changed with height. 11.4 Other Relevant Information None given. 12. Application of the Data Set These data could be used to verify the quality of the AFM-03 flux and moving window data. 13. Future Modifications and Plans None given. 14. Software 14.1 Software Description None given. 14.2 Software Access None given. 15. Data Access 15.1 Contact for Data Center/Data Access Information These BOREAS data are available from the Earth Observing System Data and Information System (EOS-DIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The BOREAS contact at ORNL is: ORNL DAAC User Services Oak Ridge National Laboratory (865) 241-3952 ornldaac@ornl.gov ornl@eos.nasa.gov 15.2 Procedures for Obtaining Data BOREAS data may be obtained through the ORNL DAAC World Wide Web site at http://www-eosdis.ornl.gov/ or users may place requests for data by telephone, electronic mail, or fax. 15.3 Output Products and Availability Requested data can be provided electronically on the ORNL DAAC's anonymous FTP site or on various media including, CD-ROMs, 8-MM tapes, or diskettes. The complete set of BOREAS data CD-ROMs, entitled "Collected Data of the Boreal Ecosystem-Atmosphere Study", edited by Newcomer, J., et al., NASA, 1999, are also available. 16. Output Products and Availability 16.1 Tape Products All time series as recorded by the investigators are saved on the NCAR Mass- Store System in NetCDF format and are available from the investigators upon request. Contact Steven Oncley or Don Lenschow. 16.2 Film Products Videotapes with imagery from forward-, side (left)-, and downward-looking cameras are also available from the investigators. The forward-looking is black and white, and the others are color. The quality is medium, since the tapes were recorded in "extended play" mode to create one tape for each (6-7 hour) flight. All videotapes have a time stamp in the image. Contact Steven Oncley for details. 16.3 Other Products These data are available on the BOREAS CD-ROM series. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation Airborne Humidity Measurements. 1987. NCAR Research Aviation Facility Bull. No. 22, Boulder, CO. Baumgardner, D. 1989. Airborne measurements for cloud microphysics. NCAR Research Aviation Facility Bull. No. 24, Boulder, CO. Flight Planning: The NCAR Electra. 1993. NCAR Research Aviation Facility Bull. No. 7, Boulder, CO. Glover, V. and L. Bannehr. 1993. Radiation measurements from NCAR aircraft. NCAR Research Aviation Facility Bull. No. 25, Boulder, CO. Lenschow, D.H. and P. Spyers-Duran. 1989. Measurement Techniques: Air motion sensing. NCAR Research Aviation Facility Bull. No. 23, Boulder, CO. 17.2 Journal Articles and Study Reports Davis, K.J. et al. 1996. 22nd Conference on Agricultural and Forest Meteorology, Atlanta, GA, Jan. 28-Feb. 2, American Meteorological Society. Lenschow, D.H., Q. Wang, S.P. Oncley, K.J. Davis, and J. Mann. 1996. Lake-induced modification of the boundary layer over the boreal forest. 22nd Conference on Agricultural and Forest Meteorology, Atlanta, GA, Jan. 28- Feb. 2, American Meteorological Society. Mann, J., K.J. Davis, D.H. Lenschow, S.P. Oncley, C. Kiemle, G. Ehret, A. Giez, and H.G. Schreiber. 1995. Airborne observations of the boundary layer top, and associated gravity waves and boundary layer structure. Ninth Symp. on Met. Obs. and Instrum., Amer. Met. Soc., Boston, MA. Oncley, S.P., D.H. Lenschow, K.J. Davis, T. Campos, and J. Mann. 1996. Regional-scale surface flux observations across the boreal forest during BOREAS. 22nd Conference on Agricultural and Forest Meteorology, Atlanta, GA, Jan. 28-Feb. 2, American Meteorological Society. Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96). Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year. Bulletin of the American Meteorological Society. 76(9):1549-1577. Sellers, P.J., F.G. Hall, R.D. Kelly, A. Black, D. Baldocchi, J. Berry, M. Ryan, K.J. Ranson, P.M. Crill, D.P. Lettenmaier, H. Margolis, J. Cihlar, J. Newcomer, D. Fitzjarrald, P.G. Jarvis, S.T. Gower, D. Halliwell, D. Williams, B. Goodison, D.E. Wickland, and F.E. Guertin. 1997. BOREAS in 1997: Experiment Overview, Scientific Results and Future Directions. Journal of Geophysical Research 102 (D24): 28,731-28,770. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None. 19. List of Acronyms AFM - Airborne Fluxes and Meteorology AGL - Above Ground Level ASCII - American Standard Code for Information Interchange ATD - Atmospheric Technology Division of NCAR BL - atmospheric Boundary Layer BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System CD-ROM - Compact Disk-Read-Only Memory DAAC - Distributed Active Archive Center EOS - Earth Observing System EOSDIS - EOS Data and Information System GPS - Global Positioning System GSFC - Goddard Space Flight Center HTML - HyperText Markup Language IFC - Intensive Field Campaign INS - Inertial Navigation System IRS - Inertial Reference System MMM - Mesoscale and Microscale Research Division, NCAR NAD83 - North American Datum of 1983 NASA - National Aeronautics and Space Administration NCAR - National Center for Atmospheric Research NDVI - Normalized Difference Vegetation Index NRC - National Research Council, Canada NSA - Northern Study Area OA - Old Aspen ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park PPFD - Photosynthetic Photon Flux Density RAF - Research Aviation Facility, NCAR SSA - Southern Study Area SSSF - Sounding and Surface System Facility, NCAR TF - Tower Flux URL - Uniform Resource Locator UTC - Universal Time Code 20. Document Information 20.1 Document Revision Date Written: 29-Sep-1995 Last Updated: 20-Jul-1999 20.2 Document Review Date(s) BORIS Review: 30-Jun-1999 Science Review: 20.3 Document ID 20.4 Citation These data were provided by the National Center for Atmospheric Research, which is sponsored by the National Science Foundation. 20.5 Document Curator 20.6 Document URL Atmospheric Pressure Wind direction Wind speed Temperature Dewpoint temperature Mixing ratio Carbon dioxide concentration Ozone concentration AFM03_Soundings.doc 08/21/99