README for the Upper Atmosphere Research Satellite (UARS) Level 3A Data Set The purpose of the following README file is to assist you to read the data. For scientific content of the data, please refer to the online Guide document. The production and distribution of this data set are being funded by NASA's Mission To Planet Earth Program. The data are not copyrighted, however we request that when you publish data or results using these data, please acknowledge as follows: "The authors would like to thank the Upper Atmosphere Research Satellite (UARS) Project, (Code 916), and the Distributed Active Archive Center (Code 902.2) at the Goddard Space Flight Center, Greenbelt, MD 20771 for the production and distribution of these data, respectively. These Activities are sponsored by NASA's Mission to Planet Earth Program." 1. DATA SET INFORMATION The Upper Atmosphere Research Satellite (UARS) level 3A data set consists of daily near global (80 N - 80 S) measurements of atmospheric trace gases, temperature, aerosols and wind profiles, as well as measurements of solar UV spectra and charged particles injected into the Earth's atmosphere. Four instruments measure chemical composition. These instruments include the Cryogenic Limb Array Etalon Spectrometer (CLAES), the Halogen Occultation Experiment (HALOE), the Improved Stratospheric and Mesospheric Sounder (ISAMS), and the Microwave Limb Sounder (MLS). Two instruments, the High-Resolution Doppler Imager (HRDI) and the Wind Imaging Interferometer (WINDII), measure winds. The Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) instrument measures the solar UV spectra in the 115 nm - 410 nm range, while the Solar-Stellar Intercomparison Experiment (SOLSTICE) instrument measures the solar UV spectra in the 119 nm - 420 nm range. The Particle Environment Monitor (PEM) instrument measures electrons, protons, and X-rays injected into the Earth's upper atmosphere. An additional instrument of opportunity, the Active Cavity Radiometer Irradiance Monitor (ACRIM II), measures the solar constant. ACRIM II data are not part of the UARS dataset, but are available as a separate dataset. Please refer to section 2 for instrument descriptions. All of the above data are archived at the Goddard Distributed Active Archive Center (DAAC). The UARS level 3A data set also includes two correlative data products for verifying geophysical parameters derived from the UARS instruments. Correlative data from the National Meteorological Center (NMC), now called the National Centers for Environmental Prediction (NCEP), includes assimilated data of temperature, winds (u and v components), moisture, and geopotential height. The correlative data from the United Kingdom Meteorological Office (UKMO) includes temperature, meridional and zonal winds, omega vertical velocity, and geopotential height parameters. The following table shows the parameters measured by the various chemistry and dynamics instruments: |CLAES|ISAMS|MLS|HALOE|HRDI|WINDII| ------------------------------------------------------------------- CF2Cl2 (vmr) | X | | | | | | ------------------------------------------------------------------- CFCl3 (vmr) | X | | | | | | ------------------------------------------------------------------- CH4 (vmr) | X | X | | X | | | ------------------------------------------------------------------- ClO (vmr) | | | X | | | | ------------------------------------------------------------------- ClONO2 (vmr) | X | | | | | | ------------------------------------------------------------------- CO (vmr) | | X | | | | | ------------------------------------------------------------------- H2O (vmr) | X | X | X | X | | | ------------------------------------------------------------------- HCl (vmr) | O | | | X | | | ------------------------------------------------------------------- HF (vmr) | | | | X | | | ------------------------------------------------------------------- HNO3 (vmr) | X | O | X | | | | ------------------------------------------------------------------- N2O (vmr) | X | X | | | | | ------------------------------------------------------------------- N2O5 (vmr) | X | X | | | | | ------------------------------------------------------------------- NO (vmr) | X | O | | X | | | ------------------------------------------------------------------- NO2 (vmr) | X | X | | X | | | ------------------------------------------------------------------- O3 (vmr) | X | X | X | X | | | ------------------------------------------------------------------- SO2 (vmr) | | | X | | | | ------------------------------------------------------------------- Aerosols (1/km) | X | X | | X | | | ------------------------------------------------------------------- Temperature (Kelvin) | X | X | X | X | X | X | ------------------------------------------------------------------- Wind (m/s) | | | | | X | X | ------------------------------------------------------------------- Volume Emission Rate (1/cm^3/s) | | | | | X | O | ------------------------------------------------------------------- ( vmr = volume mixing ratio = 10E-6 ppmv ppmv = parts per million by volume ) X - Parameter was measured, and is available from the Goddard DAAC O - Parameter was measured, but is currently not available from the Goddard DAAC 1.1 Temporal Coverage and Resolution The temporal coverage of the data for each instrument is shown below. All UARS instruments are still taking measurments, with the exception of CLAES which ceased operating in May 1993, and ISAMS which stopped taking data in July 1992 due to a mechanical problem. The MLS 183 GHz radiometer, which measures H2O and ozone, failed in April 1993. The rest of the MLS instrument is still operational. The temporal resolution of these data is daily. | Version | Data Coverage | ---------------------------------------------- CLAES | 7 | 01/09/1992 - 05/05/1993 | ---------------------------------------------- HALOE | 18 | 10/11/1991 - present | ---------------------------------------------- HRDI | 11 | 11/06/1991 - present | ---------------------------------------------- ISAMS * | 10 | 09/28/1991 - 07/29/1992 | ---------------------------------------------- MLS ** | 4 | 09/18/1991 - present | ---------------------------------------------- PEM | 3 | 10/01/1991 - present | ---------------------------------------------- SOLSTICE | 8 | 10/03/1991 - 09/30/1994 | ---------------------------------------------- SUSIM | 19 | 10/11/1991 - 09/29/1996 | ---------------------------------------------- WINDII | 9 | 12/24/1991 - 04/10/1994 | ---------------------------------------------- NMC | | 09/12/1991 - present | ---------------------------------------------- UKMO | | 10/17/1991 - present | ----------------------------------------------  * ISAMS H2O data are version 9 ** MLS H2O and O3 at 183 GHz are available from 09/18/1991 to 04/15/1993 1.2 Spatial Coverage and Resolution The latitudinal resolution of the level 3AL (latitude referenced, see section 3.2) data is 4 degrees, or about 440 km, for all instruments along the satellite orbital track, and 495 km for level 3AT (time referenced, see section 3.1) data. Vertical resolution is about 2.5 km for pressure referenced data arrays, and 3 - 5 km for altitude referenced data arrays. Spatial coverage is dependent on instrument (see section 2), and ranges between 80 degrees south and 80 degrees north. 2. SATELLITE AND INSTRUMENT Nominal orbit parameters for the Upper Atmosphere Research Satellite are: Launch Date: 12 September 1991 Orbit: near-circular Nominal Altitude (km): 585 km Inclination (deg): 57 degrees Nodal Period (min): 97 minutes Global coverage interval for full diurnal measurements: 36 days The Upper Atmospheric Research Satellite (UARS) is a three year mission, developed in response to the growing awareness that man can have a pronounced affect on the planet and surrounding atmosphere, and in particular the upper atmospheric layers that protect the Earth from harmful solar radiation. UARS was mandated in 1976, when it became evident that human activities were having a devastating affect on the protective ozone layer, mostly through the use of chlorofluorocarbons (CFCs). The UARS was outfitted with 9 instruments designed to provide the first simultaneous, comprehensive, global coverage of uppe atmosphere composition (CLAES, ISAMS, HALOE and MLS), dynamics (HRDI and WINDII), and energy input (PEM, SOLSTICE and SUSIM) data. UARS began its mission shortly after its deployment from the Space Shuttle Discovery on 12 September 1991. All dynamics and composition experiments employ limb-viewing geometry to detect characteristic wavelengths of radiation emitted by atmospheric molecules along a line-of-sight. Intensity of emitted radiation is directly proportional to the gas density. A brief description of each instrument follows. 2.1 Cryogenic Limb Array Etalon Spectrometer (CLAES) The CLAES instrument measures concentrations of members of the nitrogen (N2O, NO, NO2, N2O5 and HNO3) and chlorine (CF2Cl2 or CFC-12, CFCl3 or CFC-11, HCl, and ClONO2) families, as well as ozone, water vapor, and methane through observations of infrared thermal emissions in the spectral regions from 3.5 to 12.7. CLAES also measures aerosol and temperature profiles. The instrument consists of a telescope, a spectrometer, and a linear array of 20 detectors to obtain vertical profiles of species concentrations between 10 and 60 km. Global coverage alternates each yaw cycle (about 36 days) between 34 north and 80 south, and 34 south and 80 north. CLAES had a design lifetime of 18 months, and ceased operations on May 5, 1993. 2.2 Halogen Occultation Experiment (HALOE) The HALOE instrument measures vertical distributions of hydrofluoric and hydrochloric acids, methane, carbon dioxide, ozone, water vapor, nitric oxide, and nitrous oxide between 10 and 65 km, and 75 degrees north and 75 degrees south. HALOE also measures temperature and aerosol extinction profiles. The HALOE instrument utilizes onboard gas samples as absorbing filters in conjunction with its detectors to measure hydrofluoric and hydrochloric acid with high spectral resolution. Broadband filters are utilized to measure other gases. The instrument measures atmospheric infrared absorption in the spectral region between 2.43 to 10.25 microns, utilizing the Sun as the light source during times of spacecraft sunrise and sunset. There are 14 or 15 orbits per day, each with one sunrise and sunset, corresponding to 28 to 30 measurements per day. This instrument is still operational. 2.3 High Resolution Doppler Imager (HRDI) The HRDI instrument measures the Doppler shift of spectral lines within the atmospheric band system of molecular oxygen to determine the wind field (below 45 km, during daytime only), and to measure atomic emission lines (above 60 km, both daytime and nighttime), giving a spectral range for both levels of 557 nm to 775 nm. Wind field measurements are made in two altitude ranges: the stratosphere (10 to 45 km), and the mesosphere (60 to 110 km). Latitudinal coverage is either between 75 north and 75 south, 75 north and 40 south, or 40 north and 75 south, depending on which side of the spacecraft the instrument telescope is pointing . This instrument is currently operational. 2.4 Improved Stratospheric and Mesospheric Sounder (ISAMS) The ISAMS is a filter radiometer employing 8 detectors, which observes infrared molecular emissions by means of a movable off-axis reflecting telescope. The ISAMS experiment measures the concentrations of nitrogen chemical species (N2O, NO, NO2, N2O5 and HNO3), as well as ozone, water vapor, methane, and carbon monoxide through observations in the infrared spectral region from 4.6 to 16.6 microns. ISAMS movable off-axis telescope allows observations to be made between 80 north and 80 south. Vertical coverage is from about 15 to 80 km. This instrument suffered a mechanical problem, thus there are no data after July 29, 1992. 2.5 Microwave Limb Sounder (MLS) The MLS instrument measures the emissions of chlorine monoxide, water vapor, and ozone in the microwave spectral region at frequencies of 63, 183, and 205 GHz (4.8, 1.64, 1.46 mm). The MLS measurement of chlorine monoxide is of particular importance, due to its role as a catalyst in the destruction of ozone. The instrument's microwave antenna scans the vertical from 15 to 85 km. Latitudinal coverage alternates each yaw cycle (about 36 days) between 34 north and 80 south, and 34 south and 80 north. The 183 GHz radiometer failed in April 1993; consequently, there are no water vapor and 183 GHz ozone data after April 20, 1993. The rest of the MLS instrument is still operational. 2.6 Particle Environment Monitor (PEM) The PEM instrument measures the type, amount, energy, and distribution of charged particles injected into the Earth's thermosphere, mesosphere, and stratosphere from between 80 north and 80 south. This instrument utilizes three separate boom-mounted sensors to measure the energies for electrons from 1 eV to 150 eV, protons from 1 eV to 5 MeV, and the strength of the Earth's Magnetic field. The PEM instrument also includes a 16-element array of X-ray detectors to provide wide spatial coverage of the energy injected into the upper atmosphere. These detectors will provide X-ray images in the energy range from 2 to 50 keV. This instrument is currently operational. 2.7 Solar/Stellar Irradiance Comparison Experiment (SOLSTICE) This instrument consists of a spectrometer with three spectral channels which utilizes light from the Sun during the daylight portion of the orbit, and light from certain designated stars for calibration during the nighttime portion of its orbit. This instrument measures solar ultraviolet radiation in the wavelength range from 115 to 430 nm, with a spectral range of 0.12 nm. This instrument is still operational. 2.8 Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) SUSIM measures ultraviolet radiation in the wavelength range from 120 - 400 nm, with a spectral resolution of 0.10 nm. This instrument consists of two spectrometers, seven detectors, and 4 deuterium ultraviolet calibration lamps designed to provide both measurements of solar ultraviolet radiation, and its own long term, absolute calibration light sources to track changes in instrument response. This instrument is currently operational. 2.9 Wind Imaging Interferometer (WINDII) The WINDII instrument, utilizing a Michelson interferometer to sense atmospheric emissions in the visible and near-infrared spectral ranges (557 nm - 900 nm). This instrument measures the velocity of upper- atmospheric wind fields through the measurement of Doppler shifts of molecular and atomic emission lines above 80km during daytime and nighttime. WINDII measures wind fields from about 75 north to 75 south. This instrument is still operational. 2.10 Active Cavity Radiometer Irradiance Monitor (ACRIM II) The Active Cavity Radiometer Irradiance Monitor (ACRIM II) was included on the UARS platform as an instrument of opportunity. Its objective is to measure total solar irradiance (solar constant), which is especially important to climate studies. This instrument is currently operational. Note: ACRIM II is not part of the UARS level 3A data set. 3. DATA SET ORGANIZATION All UARS level 3A scientific instrument data are maintained in files (PROD extension) containing data from one instrument and parameter per day. The level 3A file formats are referred to as 3AT (time referenced), 3AL (latitude referenced), or 3AS/3BS (solar data). In addition to the level 3A data files, there may also be an associated level 3A parameter file. These parameter files (designated as level 3LP for the 3AL files, and level 3TP for the 3AT files) provide information not contained in the level 3A data files, such as data quality and auxiliary information useful for interpreting the science data in the corresponding 3AL or 3AT file. Additionally, each UARS data file is accompanied by an ASCII metadata file (META extension), containing the data attributes for these UARS data files. These metadata files are used to map the UARS data (PROD extension) to the corresponding data attributes. The file structures for all level 3AL, 3AT, 3LP, 3TP, and 3AS/3BS data files are similar. The record sequence is as follows: Record # Description -------- ----------- 1 SFDU Label Record 2 Header Label Record 3-n Data Records The first record is the SFDU label record. The SFDU record identifies the file as an SFDU-formatted file and "points" to detailed file and record structure documentation. The second record is the header label record containing the instrument, parameter, latitude range, altitude or pressure level range, date, and other useful information pertaining to the processing of the level 3A data. All following records contain the data and quality (standard deviation or variance) values. More detailed information can be found in the Standard Formatted Data Units (SFDU) documents available from the Goddard DAAC. The file formats available from the Goddard DAAC are not the same VAX VMS based file formats, that have been available from the UARS Central Data Handling Facility (CDHF). 3.1 Level 3AT (Time Referenced) Data Format. A Level 3AT file consists of a time-ordered collection of data records. Each data record contains a single array of data values for one parameter or species type at 65.536 second intervals. This corresponds to about 495 km along the orbital track between data records. The reference time values at which Level 3AT records are created are common across all Level 3AT files from all instruments. Level 3AT data records are fixed length. The record length is contained in the corresponding ASCII metadata file. Level 3AT files are generated by the CLAES, HALOE, HRDI, ISAMS, MLS, PEM, and WINDII instrument investigations. The index into the data array may correspond to standard pressure levels or standard altitude levels. The standard pressure level values in millibars are given by: P(i) = 1000.0 * ( 10**( -i/6)), where i = 0,1,2,.....45. The CLAES, HALOE, HRDI, ISAMS, and MLS instrument data use pressure referenced data arrays. It should be noted that not all species within a data product will contain all 45 pressure levels. The standard altitude level values in kilometers are given by: Z(i) = 5 * i , for 0 < i <= 12 Z(i) = 60 + (i - 12) * 3 , for 13 <= i <= 32 Z(i) = 120 + (i - 32) * 5 , for 33 <= i <= 88. The HRDI, PEM, and WINDII instrument data use altitude referenced data arrays. It should be noted that not all species within a data product will contain all 88 altitude levels. The HRDI and WINDII instrument investigations produce altitude and/or pressure referenced data. To distinguish between the altitude and pressure referenced data for the same specie at the same data level, additional information is included with the data specie of the UARS file name. 3.2 Level 3AL (Latitude Referenced) Data Format. A Level 3AL data file consists of a collection of profiles of atmospheric data that have been sorted by both latitude and time. Each data file contains a single array of data values for one parameter or species type. The standard latitude values at which Level 3AL records may be written are from -88.0 degrees to +88.0 degrees latitude in 4.0 degree increments. The level 3AL data values are derived from the associated level 3AT data by interpolating to the nearest 4 degree latitude along the orbital track. Level 3AL data records are fixed length. The record length is contained in the corresponding ASCII metadata file. Level 3AL files are generated by the MLS, ISAMS, CLAES, HRDI, and WINDII instrument investigations. The index into the data array may correspond to standard pressure levels or standard altitude levels. For more information see section 3.1 above. 3.3 Level 3AS/3BS (Solar Data) Data Format. Level 3AS and level 3BS files contain a single data record, for a UARS day, containing a single array representing a daily mean solar spectrum. The level 3AS data files contain uncalibrated data , while the level 3BS files contain calibrated solar data. The Goddard DAAC currently archives only level 3BS data. The Level 3AS/3BS files are stored as flat files without any index structure. All records of a given file are of the same length. The actual record length is dependent upon the maximum number of data points that can be stored in the data record. Information on the record length can be found in the corresponding ASCII metadata file. The index into the array corresponds to standard wavelength values. Each element of the array is associated with a 1.0 nanometer (nm) interval centered on the half nm between 115 nm and 425 nm, with each element of the data array containing the daily average set of observations for the wavelength bin associated with it. Additional information will also be stored in the record via a parameter array. The additional items are instrument specific, for detailed information please refer to corresponding SFDU for each instrument. Level 3AS/3BS files are generated by the SUSIM and SOLSTICE instrument investigations. The Goddard DAAC archives and distributes the level 3BS data only, at this time. 3.4 Level 3A Parameter File Format. Level 3A Parameter Files, contain additional parameters and items which were not included in the 3AL or 3AT data files. The parameters are defined by each Principal Investigator (PI) for his/her own Level 3A data. Level 3A Parameter Files will contain information describing the context of the Level 3A data with each Level 3A data record associated with a corresponding parameter file record. Level 3A Parameter Files are identified by their own distinct level. The levels used to identify Level 3A parameter files are Level 3TP which refers to time ordered parameter files associated with level 3AT files, and Level 3LP which refers to parameter files associated with level 3AL files, sorted by both latitude and time value. Level 3TP files have the same organization as the Level 3AT files (see section 3.1 above), and level 3LP files have the same organization as the Level 3AL files (see section 3.2 above). Level 3A parameter files are generated by the MLS, ISAMS, and HALOE. PEM produces data products containing electron and proton measurements by individual sensor, High-Energy Particle Spectrometer HEPS and Medium-Energy Particle Spectrometer MEPS, using the 3TP file format. These products are at a higher temporal resolution, 2.048 sec for HEPS and 65.536 sec for MEPS, than the corresponding electron and proton level 3AT data products, which are only produced when there are simultaneous HEPS and MEPS measurements. Altitude coverage is the same as in the 3AT files (see section 3.1 above). 3.5 Correlative NMC File Format. The correlative NMC data files each contain one header record followed by data records. The header record includes information such as the start and end times, latitude range, altitude/pressure range, size of the correlative data records (16964 byte fixed length), and the total number of records in the file. Each data record contains data for one hemisphere at a single pressure altitude referenced to 12:00 GMT. The data are gridded on the standard 65x65 NMC polar stereographic grid oriented 80W (Grid increment 381 km at 60N) and 100E (grid increment 381 km at 60S). The poles are at array element [33,33]. The highest pressure (lowest altitude) record is first in each series of records. The pressure levels (in millibars) for NMC data are: 1000, 850, 700, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, 10, 5, 2, 1, 0.4 The NMC temperature and geopotential height data are calculated at all 18 pressure levels. Moisture data are calculated only for the first 6 pressure levels, and only in the northern hemisphere. Wind field data are obtained for the first 12 pressure levels (up to 50 mb) in the northern hemisphere, and only the first 4 pressure levels in the southern hemisphere. Data used in the NMC analysis are purely from standard NMC sources, such as NOAA satellites, radiosondes from the worldwide network, aircraft, and any other available data transmitted to NMC. The correlative NMC data are intended to provide an independent analysis of the UARS instrument data. 3.6 Correlative UKMO File Format. The correlative UKMO data files each contain one header record followed by data records. The header record includes information such as the start and end times, latitude range, altitude/pressure range, size of the correlative data records (28288 byte fixed length), the total number of records, and the measured parameters in the file. Each data record contains data at a single pressure altitude referenced to 12:00 GMT. The data are referenced to the UARS standard pressure levels given by: P(i) = 1000*10^(-i/6) mb from 1000 mb to 0.316 mb, or levels 0 to 21. The spatial resolution of the data are 2.5 degrees latitude by 3.75 degrees longitude, using a staggered grid system. For geopotential height and tempereture data, each horizontal field consists of 73 rows of 96 points each, ordered North to South, West to East, starting at 90N, 0E. The wind grid, including vertical velocity, is staggered by half a grid length, starting at 88.75N, 1.875E (with 72 rows). The UARS assimilation system has been developed from the new UKMO data assimilation scheme for operational weather forecasting. UARS instrument data may be validated using the results from the UKMO assimilations. Note: vertical velocity (omega) data are not available prior to August 26, 1992. 4. DATA ACCESS INFORMATION UARS level 3A instrument data are archived at the Goddard DAAC. For an update of the available data, see the IMS News section under Options, or contact the DAAC User Services Office (see section 6 below). 4.1 UARS File Naming Convention and Granule Description The naming convention for UARS files distributed by the Goddard DAAC is as follows: TYPE_Lnnn_Snnnn_Dnnnn.Vnnnn_Cnn_XXXX | | | | | | | | | | | | | - File extension ( e.g. META or PROD) | | | | | | | | | | | - Cycle number of file ( e.g. C01 ) | | | | | | | | | - Version number of file ( e.g. V0003 ) | | | | | | | - UARS acquisition day ( e.g. D0001 = 12-SEP-1991 ) | | | | | - Subtype or parameter ( e.g. STEMP ) | | | - UARS processing level ( e.g. 3AT ) | - Instrument or correlative (CORR) type ( e.g. MLS ) For correlative files the level Lnnn section is replaced by source Znnn (valids entries are NMC and UKMO). The UKMO files also include the PI field Pnnn which precedes the version number field. The WINDII and HRDI files include additional information within the subtype field to differentiate the altitude referenced from the pressured referenced data. An '_A' (altitude referenced) or '_P' (pressure referenced) will be appended to the subtype field in this situation. For a full description of the naming convention see the "meta_desc.doc" file available from the IMS Document/Software section under Options. The UARS data are distributed by the Goddard DAAC in a form referred to as a data granule. A data granule is the smallest orderable amount of data, that the Goddard DAAC manages. For the UARS 3A data, a granule is one day of one parameter for one instrument. A granule will consist of a data file (PROD extension) and a small ASCII metadata file (META extension), and for HALOE, ISAMS and MLS will be accompanied by parameter file (PROD and META) pair. In addition to the data files, an order will be packaged with documentation and software: o Level 3A SFDU document(s) (depends on instrument type) o Level 3A README (this file) o Level 3A read software (see section 4.4) o Instrument-specific data quality document (if available) o Metadata description file o Yaw, roll orbit maneuver files 4.2 Getting the Data The UARS level 3A data files can be obtained from the Goddard DAAC by several mechanisms. These include the following: o Anonymous FTP. The entire HALOE 3AT, SOLSTICE 3BS, and SUSIM 3BS data sets can be downloaded from the DAAC anonymous FTP server (ftp daac.gsfc.nasa.gov). This area can also be accessed through the World Wide Web at ftp://daac.gsfc.nasa.gov/data/uars. For convenience, the data files are arranged in directories by instrument, level, parameter, year and month (e.g. /data/uars/haloe/3at/hcl/1993/10). Additionally, the DAAC keeps the most recent month (about 2 months from present) of available level 3A HRDI, MLS, and PEM, as well as correlative NMC and UKMO data online for users to download via anonymous ftp. After about one month, usually around the 20th, these data will be removed and the next month will be placed online. The data are in directories by instrument or correlative type, level or correlative source, and parameter (e.g. /data/uars/mls/3at/clo). The older data can be ordered from the DAAC through its Web archive search or the telnet based IMS system (see below). o The DAAC Web-Based Archive Interface provides a means for searching and ordering data. To search the data holdings and place an order, go to the DAAC Home Page located at "http://daac.gsfc.nasa.gov/", and click on the "Search and Order" icon. Next, fill in your user profile. Then proceed to the "Data Set" link, and choose "UARS". o EOSDIS V0 Web Gateway. You can place orders for the UARS data through the Earth Observing System Data and Information System (EOSDIS) Earth Science Web Gateway. From here you can also order data products from other data centers. The web address for the EOSDIS V0 Web Gateway is "http://harp.gsfc.nasa.gov/ims-bin/pub/imswelcome". o The Goddard DAAC online Information Management System (IMS), also provides online search and order capabilities for the UARS and other data sets. The IMS is a character based interface for VT100 emulators. To connect to the DAAC IMS: telnet daac.gsfc.nasa.gov Username: daacims Password: gsfcdaac o DAAC Help Desk. Data can also be obtained by contacting the GSFC DAAC Help Desk at: phone: 301-614-5224 or 1-800-257-6151 fax: 301-286-1775 e-mail: daacuso@daac.gsfc.nasa.gov Data can be ordered via FTP or on the following media: 8mm tape (8200 or 8500 format), 4mm tape (60 meter or 90 meter), or 9-track 6250 bpi. Magnetic tape requests can be sent via US Postal mail, or picked up in person at the DAAC. All services, including postage, are free. 4.3 Reading Tapes If you obtained data by FTP, please go to Section 4.4. Data are available on 4mm (DAT), high or low density 8 mm (Exabyte), and 6250 bpi 9-track tapes. Tapes are created with UNIX utilities "dd" and "tar" on a Silicon Graphics 440 system. The no-swap device factor of 127. Tapes may be requested in "dd" or "tar" file format. Each tape distributed by the Goddard DAAC contains printed paper labels with the names of the files it contains in the order they were written. The same utility that was used to create the tape, "dd" or "tar", must be used to access the data. To read a "tar" format tape on a computer with a UNIX operating system, use the command: tar xvfb 127 where xvbf are tar command key arguments: x indicates that the data are to be read from tape v requests verbose output; i.e., file names will be listed b states that a blocking factor is specified f states that an archive name is specified The fields in < > are system specific and may specify a device such as a tape drive, or a file directory. The specific parameter depends upon your local workstation configuration (e.g., this will be "/dev/8mm1nr" if you read the tape off the 8mm1 tape drive on the DAAC computer and with the "no rewind" option). 127 is the blocking factor To read a tar format tape on a VAX computer with a VMS operating system, you will need vmstar public domain software. Use the command: mount /FOREIGN/RECORD=512/BLOCK=65024 vmstar xvf To get vmstar, log into the Western Kentucky University anonymous FTP server using the command: ftp ftp.wku.edu Log into the "fileserv" directory using the command cd vms/fileserv and download the file VMSTAR.ZIP to your workstation using the FTP "get" or "mget" commands. Then follow the instructions for installation and unpacking in the README files. To read a "dd" format tape on a computer with a UNIX operating system, use the command: dd if= of= bs=65024 where if= specifies the tape drive with "no rewind" option (e.g., if=/dev/8mm1nr for the DAAC computer) of= specifies the desired output file name bs=65024 indicates the block size in bytes To read "dd" format tapes on a VAX computer with a VMS operating system, simply use the "copy" command. 4.4 Available Read Routines. Read routines for all the UARS instrument and correlative data are available through the Goddard DAAC IMS. These may be accessed from the OPTIONS Menu item, by choosing Document/Software List, and then choosing "UARS Level 3A Read/Dump Software" from the list displayed. The available read routines, written in both C and FORTRAN, are contained in the Unix compressed tar file readump_sw.tar.Z, which includes the following: read_uars_F - Unix shell script for FORTRAN programs read_uars_c - Unix shell script for C programs readump/ - directory containing Makefile Makefile - to compile source code programs readump/bin/ - directory for compiled programs readump/src/ - directory for souce code FORTRAN program source code: ---------------------------- READUMP_L3AL_DATA.F - reads all 3AL files READUMP_L3ASBS_DATA.F - reads all 3AS/3BS files READUMP_L3AT_DATA.F - reads all 3AT files READUMP_ISAMS_L3LP_DATA.F - reads ISAMS 3LP files READUMP_ISAMS_L3TP_DATA.F - reads ISAMS 3TP files READUMP_HALOE_L3TP_DATA.F - reads HALOE 3TP files READUMP_MLS_L3LP_DATA.F - reads MLS 3LP files READUMP_MLS_L3TP_DATA.F - reads MLS 3TP files READUMP_PEM_L3TP_DATA.F - reads PEM 3TP files READUMP_WINDII_L3LP_DATA.F - reads WINDII 3LP files READUMP_WINDII_L3TP_DATA.F - reads WINDII 3TP files READUMP_NMC_DATA.F - reads NMC files READUMP_UKMO_DATA.F - reads UKMO files C program source code: ---------------------- readump_l3al_data.c - reads all 3AL files readump_l3asbs_data.c - reads all 3AS/3BS files readump_l3at_data.c - reads all 3AT files readump_isams_l3lp_data.c - reads ISAMS 3LP files readump_isams_l3tp_data.c - reads ISAMS 3TP files readump_haloe_l3tp_data.c - reads HALOE 3TP files readump_mls_l3lp_data.c - reads MLS 3LP files readump_mls_l3tp_data.c - reads MLS 3TP files readump_pem_l3tp_data.c - reads PEM 3TP files readump_windii_l3lp_data.c - reads WINDII 3LP files readump_windii_l3tp_data.c - reads WINDII 3TP files readump_nmc_data.c - reads NMC files readump_ukmo_data.c - reads UKMO files 4.5 Reading the UARS Data Files 4.5.1 DAAC software for accessing the UARS data Simple read/dump programs for all of the UARS level 3 data file types are available through the Goddard DAAC (see section 4.4): L3AL, L3AT, L3AS/BS, HALOE L3TP, ISAMS L3LP, ISAMS L3TP, MLS L3LP, MLS L3TP, PEM L3TP, NMC Correlative, and UKMO Correlative. Both FORTRAN and C versions of the read programs are available for each data type. These programs have been tested and the results validated on SGI platforms, using IRIX operating system. To compile the programs, just type: f77 FILE_NAME.F -o FILE_NAME (for the Fortran programs) or cc file_name.c -o file_name (for the C programs). These programs simply dump the file contents to the screen. Both the C and Fortran programs require the META file, containing data file attributes, as the input parameter in order to read the PROD file, containing the actual data. example: $ READUMP_L3AT_DATA (Fortran program) PLEASE ENTER META DATA FILE NAME BELOW: MLS_L3AT_SH2O_D0001.V0003_C01_META or $ readump_l3at_data MLS_L3AT_SH2O_D0001.V0003_C01_META (C program) The entire file contents will be printed to the screen. You may want to send the output to a file (e.g. readump_l3at_data XX.XX_META > file.dat), or pipe the output through more (e.g. readump_l3at_data XX.XX_META | more). The data files are in UNIX format (floating values are IEEE format), and should be used on a 32 bit architecture machine running a UNIX operating system. The META and PROD files must be kept in the same directory because the programs require the META file as the input parameter in order to read the PROD file. The META file is necessary because it contains file record length information, which is not in the PROD files. Additionally, UARS file names should not be changed if at all possible, as the read routines may not work. A more detailed description of the META files may be found in "meta_desc.doc", available through the Goddard DAAC IMS. 4.5.2 DAAC software tools The Goddard DAAC has created a shell script called "read_uars" to allow the users to immediately view the data they have ordered. This tool interfaces with simple read/dump programs for all of the UARS level 3A data files. To use the script, following the installation instructions provided below. For a more detailed description of this procedure, consult the readump_README. Install the GSFC DAAC "read_uars" tool by uncompressing and untaring the file "readump_sw.tar.Z" Enter the command uncompress -c readump_sw.tar.Z | tar -xvf - This will create the source and binary directories within a new directory called "readump". Create the executables in a bin directory by changing to the readump directory ( cd readump ) and entering the command make The available makefile options will listed in the following menu form: Please choose the appropriate make option, then type 'make OPTION' (e.g. make SGIF) HPC compile C programs (HP machine) SGIC compile C programs (SGI machine) SUNC compile C programs (SUN machine) HPF compile Fortran programs (HP machine) SGIF compile Fortran programs (SGI machine) SUNF compile Fortran programs (SUN machine) Once you have compiled your programs, return to the directory containing the two "read_uars" programs ( cd .. ) If you used the C compiler, type the following command lines mv read_uars_F readump/. mv read_uars_c read_uars rm readump_sw.tar.Z If you used the Fortran compiler, type the following command lines mv read_uars_c readump/. mv read_uars_F read_uars rm readump_sw.tar.Z You may now use the "read_uars" tool to dump the contents of a file either to the screen, or to a file. Copy your data files to the directory containing the "read_uars" program. * Make sure that each granule came with a data file (PROD extension), and its accompanying metadata file (META extension). The metadata file is required because it contains the record length information for the data file. An example when outputting to the screen: $ read_uars The following data files are available for reading : 1) HALOE_L3AT_SHCL_D0031.V0017_C01_PROD 2) HALOE_L3AT_SHCL_D0032.V0017_C01_PROD Please enter the number of the file you want to read : 1 The following command can be substituted when outputting to a file (and screen) $ read_uars | tee -a The following command can be substituted when outputting to the screen a page at a time using the "more" command. $ read_uars | more 5. REFERENCES Special UARS Section, "Journal of Geophysical Research", Vol 98, No D6, p. 10643 - 10814, June 20, 1993. Evaluation of the UARS Data, "American Geophysical Union", Washington, D.C., 1996. 5.1 Additional Documentation Available Online at the Goddard DAAC "UPPER ATMOSPHERE RESEARCH SATELLITE MICROWAVE LIMB SOUNDER Standard Formatted Data Units Whole Data Set Document" November 1993. UARS CLAES CHANGE HISTORY SFDU: CLAES Standard Formatted Data Units Data Set Change History Document UARS CLAES L2 SFDU: CLAES Standard Formatted Data Units Level 2 Time-Ordered Atmospheric Profiles UARS CLAES L3AL SFDU: CLAES Standard Formatted Data Units Level 3AL Time-Ordered Latitude Data UARS CLAES L3AT SFDU: CLAES Standard Formatted Data Units Level 3AT Time-Ordered Data UARS CLAES WHOLE DATA SET SFDU: CLAES Standard Formatted Data Units Whole Data Set Document UARS GENERIC LEVEL 3AL SFDU: Level 3AL Data Structure in SFDU UARS GENERIC LEVEL 3AS/3BS SFDU: Level 3AS/3BS Data Structure in SFDU UARS GENERIC LEVEL 3AT SFDU: Level 3AT Data Structure in SFDU UARS GENERIC LEVEL 3LP SFDU: Level 3LP Data Structure in SFDU UARS GENERIC LEVEL 3TP SFDU: Level 3TP Data Structure in SFDU UARS HALOE L2 SFDU: HALOE Level 2 SFDU Metadata Document UARS HALOE L3A SFDU: HALOE Level 3AT/3TP Meta Document UARS HRDI L3AL SFDU: HRDI Level 3AL Data Structure in UARS Standard Documentation Format UARS HRDI L3AT SFDU: HRDI Level 3AT Data Structure in UARS Standard Documentation Format UARS HRDI QUALITY SUMMARY: HRDI Version 7 Product Quality Summary UARS ISAMS L2 SFDU: ISAMS Level 2 Data Structure in UARS Standard Documentation Format UARS ISAMS L3A SFDU: ISAMS Level 3A Data Structure in UARS Standard Documentation Format UARS ISAMS QUALITY SUMMARY: ISAMS Version 8 Product Quality Summary UARS META FILE DESCRIPTION: UARS granule level file (_meta) description UARS MLS L2 SFDU: Standard Formatted Data Units File Class Document for MLS Level 2 Data File UARS MLS L3AL SFDU: Standard Formatted Data Units File Class Document for MLS Level 3AL Data File UARS MLS L3AT SFDU: Standard Formatted Data Units File Class Document for MLS Level 3AT Data File UARS MLS L3LP SFDU: Standard Formatted Data Units File Class Document for MLS Level 3LP Parameter File UARS MLS L3TP SFDU: Standard Formatted Data Units File Class Document for MLS Level 3TP Parameter File UARS MLS QUALITY SUMMARY: MLS Version 3 Product Quality Summary UARS MLS WHOLE DATA SET SFDU: Standard Formatted Data Units Whole Data Set Document UARS NMC DATA RICHNESS SFDU: Documentation of NMC geographical data richness file UARS NMC GRIDDED DATA SFDU: Documentation of NMC gridded data produced for UARS project UARS PEM L3AT ELECTRON SFDU: PEM Electron Level 3AT Data Description in SFDU Format UARS PEM L3AT PROTON SFDU: PEM Proton Level 3AT Data Description in SFDU Format UARS PEM L3AT X-RAY SFDU: PEM X-Ray Level 3AT Data Description in SFDU Format UARS PEM QUALITY SUMMARY: PEM Level 3 Data Quality Document UARS PEM WHOLE DATA SET SFDU: PEM Level 2 Whole Data Set Supplement UARS SOLSTICE L3BS SFDU: SOLSTICE Level 3BS Data Structure in SFDU (Standard Formatted Data Units) UARS SUSIM L3 SFDU: SUSIM Level 3 Data Description and Structure UARS SUSIM QUALITY SUMMARY: SUSIM Level 3 Version 14 Data Quality Document UARS SUSIM WHOLE DATA SET SFDU: SUSIM Whole Data Set Description UARS UKMO ASSIMILATION DATA SFDU: Documentation of Analyses produced for the UARS project using Data Assimilation UARS UKMO QUALITY SUMMARY: UK Met Office Correlative Analyses 6. POINTS OF CONTACT The DAAC Help Desk: The DAAC Help Desk provides additional information on the Goddard DAAC system capabilities, and other supported data sets. The Help Desk can be reached at: GSFC DAAC Help Desk Code 902 NASA Goddard Space Flight Center Greenbelt, MD 20771 phone: 301-614-5224 or 1-800-257-6151 fax: 301-286-1775 e-mail: daacuso@daac.gsfc.nasa.gov Data Producer Information: UARS Central Data Handling Facility Steve Bove NASA Goddard Space Flight Center Mailstop 517.6 Greenbelt, MD 20771 phone: 301-286-4279 e-mail: bove@cdhf2.gsfc.nasa.gov 7. DATA SET UPDATES The Goddard DAAC will continue to archive new UARS level 3A HALOE, HRDI, MLS and PEM, as well as Correlative NMC and UKMO data in a near-realtime mode (about 2 months from current date). Some of the currently archived instrument data may be reprocessed by the Principle Investigator teams. When this happens, the new versions of the data will be made public as soon as the data are available. The UARS Data Systems Working Group (DSWG) is investigating the possibility of storing all UARS level 3A data in the Hierarchical Data Format (HDF). Last update: June 26, 1997