Aerosol Profiles from SAGE I and SAGE II 1. TYPE OF DATA 1.1 Parameter/Measurement 1.2 Unit of Measurement 1.3 Data Source 1.4 Data Set Identification 2. SPATIAL CHARACTERISTICS 2.1 Spatial Coverage 2.2 Spatial Resolution 3. TEMPORAL CHARACTERISTICS 3.1 Temporal Coverage 3.2 Temporal Resolution 4. INSTRUMENT DESCRIPTION 5. DATA PROCESSING SEQUENCE 5.1 Processing Steps and Data Sets 5.2 Derivation Techniques/Algorithms 5.3 Special Corrections/Adjustments 5.4 Processing Changes 6. QUALITY ASSESSMENT 6.1 Data Validation by Producer 6.2 Confidence Level/Accuracy Judgment 6.3 Usage Guidance 7. CONTACTS FOR DATA PRODUCTION INFORMATION 8. OUTPUT PRODUCTS AND AVAILABILITY 8.1 Tape Products 8.2 Film Products 8.3 Other Products 9. DATA ACCESS 9.1 Archive Identification 9.2 Procedures for Obtaining Data 9.3 NCDS Status/Plans 10. CONTACTS FOR ARCHIVE/DATA ACCESS INFORMATION 11. REFERENCES 11.1 Satellite/Instrument/Data Processing Documentation 11.2 Journal Articles and Study Reports 11.3 Archive/DBMS Usage Documentation 12. RELATED DATA SETS 13. SUMMARY/SAMPLE 14. NOTES ENDOFTOC 1. TYPE OF DATA 1.1 Parameter/Measurement. Atmospheric mixing ratio profiles and number density profiles for aerosol are measured during spacecraft sunrise and sunset. 1.2 Unit of Measurement. Parameter Unit --------- ---- Aerosol Extinction Coefficient 1.0E-4 km**-1 Rayleigh Extinction Coefficient 1.0E-4 km**-1 Aerosol Extinction Ratio (1.0 micrometer only) ---- 1.3 Data Source. Parameters are derived from the Stratospheric Aerosol and Gas Experiment (SAGE I) instrument on the Applications Explorer Mission-2 (AEM-2) spacecraft, and the SAGE II instrument on the Earth Radiation Budget Experiment Satellite (ERBS). 1.4 Data Set Identification. The AEM-2 SAGE I and ERBS SAGE II aerosol profile data sets are identified within NCDS as SAGEI-PROF_AEROSOLS and SAGEII-PROF_AEROSOLS. The data sets contain derived aerosol and Rayleigh extinction coefficients, total extinction ratios, and corresponding error arrays for each sunrise and sunset event. 2. SPATIAL CHARACTERISTICS 2.1 Spatial Coverage. The orbital characteristics of SAGE I and SAGE II provide near-global coverage of aerosol measurements. Low- and mid- latitude coverage is obtained from both SAGE I and SAGE II. Each instrument observes one sunrise and one sunset per orbit. Within NCDS, sunrise events are identified as "0" and sunset events are identified as "1". SAGE I: There are 15 sunrise and 15 sunset events per day. SAGE I events offer latitudinal sweep ranges of approximately 130 degrees within a 4 week period. In addition, they provide global coverage from 72 degrees north to 72 degrees south latitude during a year. Successive observations of the same type are separated by approximately 24 degrees longitude. SAGE II: Spatial coverage is similar to that of SAGE I; however, coverage is provided from 80 degrees south to 80 degrees north annually. 2.2 Spatial Resolution. The spatial resolution of the SAGE I and SAGE II data sets is the same. The 1 micrometer wavelength measurement has a vertical resolution of 1 kilometer below 25 km and a resolution of 5 km above 25 km. The vertical resolution of the 0.45 micrometer wavelength channel is 3 km below 25 km. The horizontal resolution is about 250 km for all wavelengths. 3. TEMPORAL CHARACTERISTICS 3.1 Temporal Coverage. SAGE I data collection began February 21, 1979. Four months after launch, a spacecraft power subsystem problem forced SAGE I data collection to be limited to sunsets only. Limited operation continued until November 18, 1981. SAGE II data collection began October 5, 1984 and continues to the present time. 3.2 Temporal Resolution. Each satellite instrument makes two aerosol profile determinations per orbit. SAGE I and SAGE II each have 15 orbits per day. 4. INSTRUMENT DESCRIPTION 4.1 Mission Objectives. The mission objectives of the SAGE I and SAGE II are to determine the spatial distribution and to map vertical profiles of stratospheric aerosols. Specific objectives are: a. To develop a viable satellite-based remote sensing technique for measuring stratospheric aerosols, nitrogen dioxide, ozone, and water vapor. b. To utilize these measurements to study global circulation, transient stratospheric phenomena, and sources and sinks of individual species. c. To investigate aerosol optical properties using data from flight experiments and correlative observations. 4.2 Key Satellite Flight Parameters. Nominal orbit parameters for SAGE I and SAGE II are listed below: SAGE I SAGE II ------ ------- o Launch Date February 18, 1979 October 5, 1984 o Planned Duration 1 year 1 year o Actual Duration 2 years and 9 months Still operating o Orbit Non-sun synchronous Non-sun synchronous o Inclination 55 degrees 57 degrees o Nodal Period 96.8 minutes 98 minutes 4.3 Principles of Operation. SAGE I is a four-channel solar photometer with spectral bands at 0.385, 0.45, 0.60, and 1.00 micrometers. SAGE II is a seven-channel solar photometer with spectral bands at 0.385, 0.448, 0.454, 0.525, 0.600, 0.940, and 1.019 micrometers. The 0.940 um channel allows for water vapor detection. The 0.448 um channel provides an additional channel for nitrogen dioxide detection, and the 0.525 um channel provides an additional channel for aerosol detection. The remaining channels allow the separation of atmospheric extinction along the line-of-sight due to Rayleigh scattering, aerosols, ozone, nitrogen dioxide. 4.4 Instrument Measurement Geometry. The SAGE I and SAGE II instruments use the sun as a constant radiant energy source. The instrument's sensors measure the radiation that has passed through the Earth's atmosphere during sunrise and sunset. The photometers receive a vertically scanned solar image with respect to the Earth's horizon. The SAGE I photometric data are sampled at a rate of 64 samples per second per channel and digitized to 12-bit resolution. Accuracy of the sample is 1 bit. Sampling occurs twice per orbit for durations varying from 3 to 10 minutes each, depending on the angle between the orbit plane of the spacecraft and the Earth-Sun vector. The SAGE I field-of-view, approximately 0.5 arc-minutes, produces an approximate vertical resolution of 1 km at altitudes ranging from 10 km to the horizon. The nominal scan rate of the SAGE II instrument is 15 arc-minutes per second. The radiometric data are sampled at a rate of 64 samples per second per channel and digitized to 12-bit accuracy. Sampling occurs twice per orbit for durations varying from 3 to 10 minutes each. The SAGE II vertical field-of-view, approximately 0.5 arc-minutes, produces a vertical resolution of approximately 1 km at altitudes ranging from cloud tops to 10 km. 5. DATA PROCESSING SEQUENCE 5.1 Processing steps and data steps. Radiance data, along with spacecraft attitude and housekeeping data are stored aboard the satellite and transmitted four times a day to NASA/Goddard Space Flight Center (GSFC) through a ground station or TDRS relay satellite. GSFC then forwards these data to NASA/Langley Research Center (LaRC) for processing and scientific analysis. GSFC also sends spacecraft and solar ephemeris data on a separate tape containing one week of data. Data from three sources are combined at Langley to produce the SAGE I and SAGE II aerosol profiles. They include: (a) NOAA National Meteorological Center (NMC) temperature and density readings at nineteen different pressure levels in the atmosphere; (b) spacecraft position and velocity vectors as functions of time, and (c) SAGE I raw radiance data in each of the four spectral bands, or (d) SAGE II raw radiance data in each of the seven spectral bands. Atmospheric parameters are derived from these data, including aerosol, ozone, water vapor, and nitrogen dioxide density. These data are arranged into four- day periods beginning with the first day of the month. 5.2 Derivation Techniques/Algorithms. Data from each satellite sunrise and sunset event are converted to an atmospheric transmission versus tangent-height profile. The mean slant path optical depth is calculated for 1 km altitude bins using the Lambert-Beer law. The following three-step inversion is then performed: 1. The effects of Rayleigh scattering are calculated from the meteorological data and subtracted out. 2. The slant path optical depths are separated by species: aerosol, ozone, nitrogen dioxide, and water vapor. 3. Inversion from slant path optical depth to vertical extinction is performed using the Twomey modification of the Chahine nonlinear inversion. 5.3 Special Corrections/Adjustments. During the processing of SAGE I and SAGE II data, corrections are made for solar limb darkening, atmospheric refraction, and Rayleigh scattering to derive the parameter data sets. When atmospheric temperature and pressure profiles are not available to make these corrections, latitude-dependent model temperature/pressure profiles, based on standard atmospheric profiles, are provided. If model data are provided, the event containing model data is so annotated. 5.4 Processing Changes. As a result of published corrections to the NOAA temperature data at 5 mb and above, and the desire to compare SAGE I and SAGE II data for long-term trend studies, the SAGE I data have been reprocessed using improved retrieval techniques employed for SAGE II. These data have replaced the original profile data. 6. QUALITY ASSESSMENT 6.1 Data Validation by Producer. SAGE I and SAGE II results have been validated by comparison with those obtained from a wide range of sensors, including an airborne LIDAR, balloon-borne optical particle counters, impactors, spectrometer strobes, ozonesondes, ozone rocketsondes, and other satellite data sets. An extensive feedback process for SAGE II has produced a vastly improved data set from the original. Detailed information on SAGE I and SAGE II data validation can be found in Items Item 11.1 and 11.2. NASA has made facilities available at LaRC so that visiting scientists may analyze and evaluate SAGE I and SAGE II data sets with their correlative data. Predictions of SAGE II overpasses for correlative purposes are also available upon request from LaRC. 6.2 Confidence Level/Accuracy Judgment. Since measurement accuracy is a function of altitude, each atmospheric profile array is accompanied by an error array. Typically, 1.0 micrometer aerosol extinction uncertainties are less than 10 percent from cloud tops to 25 km. Uncertainties generally increase for aerosol extinction profiles at shorter wavelengths because of the stronger Rayleigh influence. 6.3 Usage Guidance. Numerous studies using SAGE I and SAGE II data have been conducted on atmospheric dynamics that use aerosols as tracers and on stratospheric chemistry, which correlates observed aerosol variability with other atmospheric species. 7. CONTACTS FOR DATA PRODUCTION INFORMATION 7.1 Sensor Scientist Dr. M. Patrick McCormick Mail Stop 475 Langley Research Center Hampton, Virginia 23665-5225 (804) 864-2669 FTS 928-2669 8. OUTPUT PRODUCTS AND AVAILABILITY 8.1 Tape Products. 8.1.1 SAGE I Profile Archival Tape, Level II Medium/Specification: 9-track, 6250-bpi computer tape. Format and Content: The tape is generated on a Control Data Corp. (CDC) Cyber-series computer. Each record contains one event and is 1488 60-bit fields in length. Each field is in CDC-Cyber floating point notation. Each record contains the event time and location, the type of event (sunrise [0] or sunset [1]), meteorological data, processing information, ground distances, quality factors for the wavelength measurements, and arrays of Rayleigh and of aerosol extinction. Data Quantity/Rate: 1 tape per year Status: Available Plans/Schedule: No additions or changes are expected. 8.1.2 SAGE II Profile Archival Tape, Level II Medium/Specification: 9-track, 6250-bpi computer tape. Format and Content: These tapes contain processed aerosol concentration profiles along with associated error estimates. Each record represents one profile and is 640 60-bit Cyber floating point words long. An end-of-tape mark is written after the last profile record. Data Quantity/Rate: Each tape contains one year of data, starting with October and ending with December of the following year. For the first year of SAGE II operation (1985), the tape also contains profiles for November, and December 1984. Status: Available. Plans/Schedule: NCDS plans to archive all SAGE II profile tapes. 8.2 Film Products. None. 8.3 Other Products. 8.3.1 SAGE I and II Aerosol Profile Common Data Formats (CDF) Medium/Specification: Magnetic disk Format and Content: The data are stored in a special data-set- independent format, designated as the Common Data Form (CDF). CDF was developed as a uniform method of storing and retrieving data on disk. Each CDF contains data and descriptions about the data. A standard software package called the "CDF Library" allows a user within an NCDS session to create and access these data and descriptions. These CDF files may be accessed within the Data Applications Subsystem of NCDS. Data Quantity/Rate: SAGEI-PROF_AEROSOL; 1 file, 36 Mb SAGEII-PROF_AEROSOLS; 5 files (1/year), 246 Mb SAGEII-PROF_MET-DATA; 1 file, 30 Mb Status: Available Plans/Schedule: Additional data will be integrated periodically as it becomes available. 8.3.2 The Greenhouse Effect Detection Experiment (GEDEX) CD-ROM Medium/Specifications: CD-ROM in ISO 9660 standard Format and Content: The data on this disk will be stored in a special data-set-independent format, designated the Common Data Format (CDF). CDF was developed as a uniform method of storing and retrieving data on disk. Each CDF contains data and descriptions about the data. A standard software package called the "CDF Library" will be included with this CD-ROM allowing a user to create and access these data and descriptions. The CD-ROM will consist of many different data sets related to the study of the Greenhouse Effect, including the SAGE I and SAGE II Aerosol Profile data sets, and the accompanying data set documentation. Quantity/Rate: 1 CD-ROM disk set. Status: This product was released in March 1992. An update is scheduled for June 1, 1992. Plans/Schedule: Users interested in this product should contact NCDS staff for more details. 9. DATA ACCESS 9.1 Archive Identification Central Data Services Facility Code 933 National Space Science Data Center Goddard Space Flight Center Greenbelt, Maryland 20771 (301) 286-6695 9.2 Procedures for Obtaining Data. Users may submit requests for data by letter, telephone, personal visit, or through the NSI DECnet computer network at NSSDC::REQUEST. Data costs are dependent on affiliation and sponsorship of the user program. Data are free to NASA personnel. Communication with the NSSDC Request Coordination Office is advised before ordering. Researchers who reside outside the USA should direct their requests to: World Data Center A for Rockets and Satellites Code 930.2 Goddard Space Flight Center Greenbelt, Maryland 20771 USA (301) 286-6695 9.3 NCDS Status/Plans. NCDS currently supports SAGE I and SAGE II profile data: aerosols, ozone, nitrogen dioxide and water vapor as well as SAGE NMC meteorological data. NSSDC supports the Meteorological, Ephemeris Raw Data Archive Tapes (MERDAT) generated from SAGE I and SAGE II. 10. CONTACTS FOR ARCHIVE/DATA ACCESS INFORMATION Request Coordination Office National Space Science Data Center Code 933-Central Data Services Facility NASA/Goddard Space Flight Center Greenbelt, Maryland 20771 PHONE: (301) 286-6695 TELEX: 89675 NASCOM GBLT TWX No: 7108289716 Goddard DAAC User Support Office NASA/Goddard Space Flight Center Code 935 Greenbelt, Maryland 20771 INTERNET:: NCDSUSO@NSSDCA.GSFC.NASA.GOV NSI DECnet: NSSDCA::NCDSUSO 11. REFERENCES 11.1 Satellite/Instrument/Data Processing Documentation a. Chu, W.P., and M.P. McCormick, 1979. "Inversion of Stratospheric Aerosol and Gaseous Constituents from Spacecraft Solar Extinction Data in the 0.38 - 1.0 Micron Wavelength Region." Appl. Optics, 18:1404-1413. b. Kent, G.S., and P-H. Wang, 1986. "SAGE II Satellite Data Set Validation." Science and Technology Corporation, Hampton, VA. NASA Contractor Report 178189. c. Mauldin, L.E., III, N.H. Zaun, M.P. McCormick, J.H. Guy, and W.P. Vaughan, 1985. "Stratospheric Aerosol and Gas Experiment II Instrument: A Functional Description." Optical Eng. 24:307-312 d. McCormick, M.P., P. Hamill, T.J. Pepin, W.P. Chu, T.J. Swissler, and L.R. McMaster, 1979. "Satellite Studies of the Stratospheric Aerosol." Bull. Amer. Meteor. Soc. 60:1038-1046. e. Russell, P.B., T.J. Swissler, M.P. McCormick, W.P. Chu, J.M. Livingston, and T.J. Pepin, 1981. "Satellite and Correlative Measurements of the Stratospheric Aerosol I: An Optical Model for Data Conversions." J. Atmos. Sci. 38:1279-1294. f. Yue, G.K, M.P. McCormick, and W.P. Chu, 1984. "A Comparative Study of Aerosol Extinction Measurements Made by the SAM II and SAGE I Satellite Experiments." J. Geophys. Res. 89:5321-5327. 11.2 Journal Articles and Study Reports a. Ackerman, M., C. Brogniez, B.S. Diallo, G. Fiocco, P. Gobbi, M. Herman, M. Jager, J. Lenoble, C. Lippens, G. Megie, J. Pelon, R. Reiter, and R. Santer, 1989. "European Validation of SAGE II Aerosol Profiles." J. Geophys. Res., 94, D6:8399-8411. b. Chu, W.P., M.P. McCormick, J. Lenoble, C. Brogniez, and P. Pruvost, 1989. "SAGE II Inversion Algorithm" J. Geophys. Res. 94, D6:8339-8351 c. Ghazi, A., Pi Wang, and M.P. McCormick, 1985. "On Radiative Damping of Planetary Waves Using Stratospheric Observations." J. Atmos. Sci. 42, 19:2032-2042. d. Kelly, K. K., A. F. Tuck et al, 1989. "Dehydration in the Lower Antarctic Stratosphere During Late Winter and Early Spring 1987," J. of Geophys. Res., 94:D9:11317-11357. e. Kent, G. S. and M. McCormick, 1988. "Remote Sensing of Stratospheric Aerosol Following the Eruption of El Chichon," Optics News, 14:11-19. f. Kent, G. S., U. O. Farrukh, P.-H. Wang and A. Deepak, 1988. "SAGE I and SAM II Measurements of 1.0 5m Aerosol Extinction in the Free Troposphere," J. of Climate and Appl. Meteorol., 27:269-279. g. Kent, G.S. and M.P. McCormick, 1984. "SAGE I and SAM II Measurements of Global Stratospheric Aerosol Optical Depth and Mass Loading." J. Geophys. Res. 89:5303-5314. h. Kent, G.S., C.R. Trepte, U.O. Farrukh, and M.P. McCormick, 1985. "Variation in the Stratospheric Aerosol Associated with North Cyclonic Polar Vortex as Measured by the SAM II Satellite Sensor." J. Atmos. Sci. 42,14:1536-1551 i. Kinne, S., O. B. Toon, G. C. et al, 1989. "Measurements of Size and Composition of Particles in Polar Stratospheric Clouds From Infrared Solar Absorption Spectra," J. of Geophys. Res., 94:D14:16481-16491. j. Livingston, J.M., and P.B. Russell, 1989. "Retrieval of Aerosol Size Distribution Moments From Multiwavelength Particulate Extinction Measurements." J. Geophys. Res. 94, D6:8425-8433. k. McCormick, M.P., October 1985. SAGE Aerosol Measurements, Vol. I - February 21, 1979 - December 1980. NASA RP 1144. l. McCormick, M.P., January 1986. SAGE Aerosol Measurements, Vol. II - January 1980 - December 31, 1980. NASA RP 1149. m. McCormick, M.P., P. Hamill, and U.O. Farrukh, 1985. "Characteristics of Polar Stratospheric Clouds as Observed by SAM II, SAGE I, and LIDAR." J. Meteor. Soc. of Japan, 63. n. McCormick M.P., and G.S. Kent, G.L. Yue, and D.M. Cunnold, 1982. "Stratospheric Aerosol Effects from Soufriere, St. Vincent as Measured by the SAGE Satellite System." Science 216:1115-1118. o. McCormick, M.P., and J.C. Larsen, 1986. "Antarctic Springtime Measurements of Ozone, Nitrogen Dioxide, and Aerosol Extinction by SAM II, SAGE, and SAGE II." Geophys. Res. Letters 13:1280- 1283. p. McCormick, M.P., H. Steele, P. Hamill, W.P. Chu, and T.J. Swissler, 1983. "Polar Stratospheric Cloud Sightings by SAM II." J. Atmos. Sci. 30:1387-97. q. McCormick, M. P., C. R. Trepte and M. C. Pitts, 1989. "Persistence of Polar Stratospheric Clouds in the Southern Polar Region," J. of Geophys. Res., 94:D9:11241-11251. r. McMaster, L.R., 1986. "Stratospheric Aerosol and Gas Experiment (SAGE II)." Presented at the 6th Conference on Atmospheric Radiation, Williamsburg, VA, May 13-19, 1986. (Extended abstracts, pp. J46-J48) s. Oberbeck, V.R., J.M. Livingston, P.B. Russell, R.F. Pueschel, J.N. Rosen, M.T. Osborn, M.A. Kritz, K.G. Snetsinger, and G.V. Ferry, 1989. "SAGE II Aerosol Validation: Selected Altitude Measurements, Including Particle Micromeasurements". J. Geophys. Res. 94, D6:8367-8380. t. Osborn, M.T., J.M. Rosen, M.P. McCormick, Pi-Huan Wang, J.M. Livingston, and T.J. Swissler, 1989. "SAGE II Aerosol Correlative Observations: Profile Measurements." J. Geophys. Res. 94, D6:8353-8366. u. Russell, P.B., and M.P. McCormick, 1989. "SAGE II Aerosol Data Validation and Initial Data Use: An Introduction and Overview." J. Geophys. Res. 94, D6:8335-8338. v. Wang, Pi-Huan, M.P. McCormick, February 1985. "Behavior of Zonal Mean Aerosol Extinction Ratio and Its Relationship with Zonal Mean Temperature During the Winter 1978-1979 Stratospheric Warming." J. Geophys. Res. 90, C2. w. Wang, Pi-Huan, and M.P. McCormick, October 1985. "Variations in Stratospheric Aerosol Optical Depth During Northern Warming." J. Geophys. Res. 90, C10. x. Wang, Pi-Huan, M.P. McCormick, L.R. McMaster, W.P. Chu, T.J. Swissler, M.T. Osborn, P.B. Russell, V.R. Oberbeck, J.M. Livingston, J.M. Rosen, D.J. Hofmann, G.W. Grams, W.H. Fuller, and G.K. Yue, 1989. "SAGE II Aerosol Data Validation Based on Retrieved Aerosol Model Size Distribution From SAGE II Aerosol Measurements." J. Geophys. Res. 94, D6:8381-8393. y. Wang, Pi-Huan, M.P. McCormick, T.J. Swissler, M.T. Osborn, W.H. Fuller, and G.K. Yue, 1989. "Inference of Stratospheric Aerosol Composition and Size Distribution From SAGE II Satellite Measurements." J. Geophys. Res. 94, D6:8435-8446. z. Woodbury, G.E., and M.P. McCormick, 1983. "Global Distribution of Cirrus Clouds Determined from SAGE I Data." Geophys. Res. Letters 10:1180-1183. aa. Woodbury, G.E., and M.P. McCormick, 1986. "Zonal and Geophysical Distribution of Cirrus Clouds Determined from SAGE Data." J. Geophys. Res. 91:2775-2785. bb. Yue, G.K., M.P. McCormick, W.P. Chu, P. Wang, and M.T. Osborn, 1989. "Comparative Studies of Aerosol Extinction Measurements Made by the SAM II and SAGE II Satellite Experiments." J. Geophys. Res., 94, D6:8412-8424. 12. RELATED DATA SETS. Several related data sets exist online through NCDS as follows: 1) The SAGE I Profile data sets contain derived mixing ratio profiles and number densities for aerosols, ozone, and nitrogen dioxide. These data sets will be available online through NCDS in Common Data Format (CDF). To access these CDFs, specify the following as input within the Data Applications subsystem of the NCDS: NCDS$DATA:SAGEI-PROF_AEROSOLS NCDS$DATA:SAGEI-PROF_NO2 NCDS$DATA:SAGEI-PROF_OZONE 2) The SAGE II Profile data sets contain derived mixing ratio profiles and number densities for aerosols, ozone, nitrogen dioxide, and water vapor. An additional data set contains the NMC meteorological profile data. These data sets will be available online by year in Common Data Format (CDF). To access these CDFs, specify the following as input within the Data Applications subsystem of the NCDS: NCDS$DATA:SAGEII-PROF_AEROSOLS NCDS$DATA:SAGEII-PROF_NO2 NCDS$DATA:SAGEII-PROF_OZONE NCDS$DATA:SAGEII-PROF_H20VAPOR NCDS$DATA:SAGEII-PROF_MET-DATA 3) The Nimbus-7 Limb Infrared Monitor of the Stratosphere (LIMS) data sets contain mixing ratio profiles of ozone, nitric acid, water vapor, and nitrogen dioxide, along with temperature and geopotential height distribution. All profiles are given as a function of pressure. These data sets are available offline through NCDS. To access these data sets, specify the following as input within the Data Application subsystem of the NCDS. Data sets are converted to Common Data Format "on the fly". NCDS$DATA:LIMS-LAMAT_DAY_GRID NCDS$DATA:LIMS-LAMAT_ZONEMEAN 4) The Nimbus-7 Stratospheric Aerosol Measurement (SAM II) Beta and Aerosol Number density Archive Tape (BANAT) data sets contain derived aerosol and Rayleigh extinction coefficients, total extinction ratios, and corresponding error arrays for each sunrise and sunset event. These data sets are available offline through NCDS. To access these data sets, specify the following as input within the Data Applications subsystem of the NCDS. Data sets are converted to Common Data Format (CDF) "on the fly". NCDS$DATA:BANAT_SUNRISE NCDS$DATA:BANAT_SUNSET 13. SUMMARY/SAMPLE. 14. NOTES. SAGE I and SAGE II meteorological profile data are provided by the NOAA National Meteorological Center (NMC). The meteorological profile data, combined with spacecraft position and velocity and SAGE I or SAGE II raw radiance data, are needed to map nitrogen dioxide, ozone, aerosol, and water vapor profiles. The meteorological data include temperature, altitude, and density profiles at 19 different pressure levels in the atmosphere. (The pressure levels themselves can be used to derive molecular (Rayleigh) scattering corrections.) In addition, the meteorological data provided by NOAA/NMC contain error estimates for both temperature and density at each of the pressure levels. These meteorological data are included as part of each SAGE I and SAGE II Profile and MERDAT data set. *92/05/14