README for the NOAA/NASA Pathfinder TIROS Operational Vertical Sounder Path A 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 accessible via the DAAC Information Management System. 1. DATA SET INFORMATION This data set contains the TIROS Operational Vertical Sounder (TOVS) level 3 geophysical parameters derived using the physical retrieval method of Susskind et al. (1984). The data were processed by the Satellite Data Utilization Office of the Goddard Laboratory for Atmospheres at NASA/GSFC. This method, which is model- and a priori data-dependent, is designated as the so-called Path A scheme by the TOVS Pathfinder Science Working Group. The data are archived at the Goddard Distributed Active Archive Center (DAAC). The primary goal of Pathfinder is the production of consistently processed, long-term data sets for use in global change studies. TOVS Pathfinder is one of several Pathfinder studies initiated by NOAA and NASA (the others being AVHRR, GOES, and SSM/I Pathfinders). As a first step in the processing, a common benchmark period was selected to facilitate the analysis and intercomparison of geophysical fields derived from the various Pathfinders. The benchmark period covers the time period April 1987 through November 1988. The 20-channel High resolution Infrared Radiation Sounder 2 (HIRS/2) and the 4-channel Microwave Sounding Unit (MSU) aboard the NOAA-xx series of Polar Orbiting Satellites are used to produce global fields of the 3-dimensional temperature-moisture structure of the atmosphere. In addition to profiles of temperature and moisture, the HIRS2/MSU data are used to derive surface skin temperature, sea surface temperature, outgoing longwave radiation, cloud fraction, cloudtop height, total integrated column ozone and precipitation estimates. The Path A system steps through an interactive forecast-retrieval- analysis cycle. In each 6-hour synoptic period, a 2nd order General Circulation Model (Takacs et al., 1994) is used to generate the 6-hour forecast fields of temperature and humidity. These global fields are used as the first guess for all soundings occurring within a 3-hour time window centered upon the forecast time. These retrievals are then assimilated with all available in situ measurements (such as radiosonde and ship reports) in the 6-hour interval using an Optimal Interpolation (OI) analysis scheme developed by the Data Assimilation Office of the Goddard Laboratory for Atmospheres. This analysis is then used to specify the initial conditions for the next 6-hour forecast, thus completing the cycle. TOVS is the only long-term source of high resolution global information pertaining to the temperature and moisture structure of the atmosphere. Because similar HIRS/2 and MSU instrumentation has flown on operational satellites from 1979 to the present, data from these instruments can make an important contribution to the understanding of the variability of atmospheric and surface parameters as well as the correlations between spatial variations of atmospheric and surface quantities. In addition, the data can potentially be used to identify and monitor trends in temperature, moisture, clouds, radiation, and precipitation, provided satellite drifts and cross-calibration of different satelites are taken into account. The full TOVS Pathfinder data set, of which the NOAA-10 benchmark period is a subset, will be processed in a consistent manner and as such will be useful for all of the applications listed above. 2. SATELLITE AND INSTRUMENT A high-level description of the NOAA-10 platform and the TOVS instruments is presented below. For more detailed information refer to Kidwell (1991). Nominal orbital parameters for the NOAA-10 spacecraft were: Launch date 9/17/86 Operational dates 11/17/86 - present Orbit Sun-synchronous, near polar Nominal Altitude (km) 833 Inclination (deg) 98.8 Nodal Period (min.) 102 Equator Crossing Time (LST) 1930 (ascending), 0730 (descending) Nodal Increment (deg) 25.3 The TOVS system consists of 3 independent instruments, specifically: o the High Resolution Infrared Radiation Sounder 2 (HIRS/2) o the Microwave Sounding Unit (MSU) o the Stratospheric Sounding Unit (SSU) All satellites in the NOAA polar orbiting series beginning with TIROS-N in 1978 contained HIRS/2 and MSU; however, both NOAA-10 and NOAA-12 contained no SSU. The HIRS/2 is a step-scanned instrument that utilizes a 15-cm diameter optical system to gather energy emitted by the earth's surface and atmosphere in 19 infrared channels, as well as reflected radiation in a single visible channel. These channels are: Channel # Wavenumber(cm-1) Channel # Wavenumber(cm-1) --------- ---------------- --------- ---------------- 1 667.7 11 1363.3 2 680.2 12 1489.4 3 691.2 13 2191.4 4 704.3 14 2208.7 5 716.3 15 2237.5 6 733.3 16 2269.1 7 750.7 17 2360.0 8 899.5 18 2514.6 9 1029.0 19 2665.4 10 1224.1 20 14453.1 The MSU is a step-scanned 4 channel Dicke radiometer which makes passive microwave measurements in the 50 GHz oxygen absorption region of the spectrum. Two 4-inch diameter antennas sense radiation in the following spectral channels: Channel # Wavenumber(cm-1) Channel # Wavenumber(cm-1) --------- ---------------- --------- ---------------- 1 1.6779 (50.30 GHz) 3 1.8334 (54.96 GHz) 2 1.7927 (53.74 GHz) 4 1.9331 (57.95 GHz) The SSU is a step-scanned far-infrared spectrometer with 3 channels in the 15 micrometer carbon dioxide absorption band. It uses the pressure modulation technique in 3 individual cells to sense radiation emitted from the 1 to 20 mb region of the atmosphere. The central wavenumber for each of the 3 cells is 668 cm-1. The instrument parameters for the TOVS sensors are: Instrument parameter HIRS/2 MSU SSU -------------------- ------ ------ ------ Cross track scan angle (+/- degrees from nadir) 49.5 47.4 40.0 Number of steps 56 11 8 Angular FOV (degrees) 1.25 7.5 10.0 Step Angle (degrees) 1.80 9.5 10.0 Ground IFOV (km) - at nadir 17.4 109.3 147.3 - at end of scan 58.5 x 29.9 323.1 x 178.8 244.0 x 186.1 Swath width (+/- km) 1120 1174 737 The channels used for Path A parameter estimation are as follows: Temp Profile H2O Profile Clouds Surf Emiss Surf Temp ------------ ----------- ---------- ---------- ------------- HIRS...1,2,4 HIRS...8,10 HIRS...4,5 MSU......1 HIRS..8,18,19 13,14,15 11,12 6,7,8 MSU......3,4 Cloud Clearing Ozone -------------- ------- HIRS.....13,14 HIRS..9 MSU..........2 3. DATA ORGANIZATION The TOVS Pathfinder level 3 output consist of binary files containing 2- and 3-dimensional geophysical parameters mapped to a rectangular latitude-longitude grid. For each parameter, each cell in the grid is characterized by a mean value of that parameter, the associated standard deviation, and the number of observations used in computing the first two quantities. These statistics are stored as Scientific Data Sets (SDSs) in the Hierarchical Data Format (HDF). Means and standard deviations are stored as 32-bit floating point words, while the number of observations or "counts" are represented as 16 bit integers. Version 3.2 release 4 of HDF (HDF3.2r4) was used to create all level 3 files. The schematic below shows the overall structure of a TOVS HDF file: -------------------------- | FILE IDENTIFIER | -------------------------- | FILE DESCRIPTION | -------------------------- | DAAC METADATA | -------------------------- | SCIENCE METADATA | -------------------------- / | \ / | \ / | \ / | \ / | \ ----------- ----------- ----------- |Parameter| |Parameter| |Parameter| | Means | | Std Dev | | Counts | ----------- ----------- ----------- / \ / \ / \ / ... \ / ... \ / ... \ --------- --------- --------- ---------- --------- ---------- | SDS 1 |...|SDS 17 | |SDS 18 |...| SDS 34 | |SDS 35 |...| SDS 51 | | TEMP | | PSURF | |TEMP_SD| |PSURF_SD| |TEMP_CT| |PSURF_CT| --------- --------- --------- ---------- --------- ---------- | ..... | | ..... | | ..... | | | | | | | -------- -------- -------- -------- -------- -------- |Labels| |Labels| |Labels| |Labels| |Labels| |Labels| -------- -------- -------- -------- -------- -------- |Scales| |Scales| |Scales| |Scales| |Scales| |Scales| -------- -------- -------- -------- -------- -------- |Type | |Type | |Type | |Type | |Type | |Type | -------- -------- -------- -------- -------- -------- Each file includes the following parameter SDSs (written out in that order): SDS Name Units Description -------- ----- ----------- (1) TEMP K Temperatures at the surface and at 1000, 850, 700, 500, 400, 300, 200, 100, 70, 50, and 30 mb (2) CLTEMP K Coarse layer mean temperature for the surface-500, 500-300, 300-100, and 100-30 mb layers (3) PRWAT cm Total precipitable water values above surface, 850, 700, 500, and 300 mb (4) TSURF K Surface skin temperature (5) FCLD 0-1 Total cloud fraction * (6) FCLDP 0-1 Cloud fraction in 7 ISSCP layers * 180 mb to top of atmosphere 180 mb to 310 mb 310 mb to 440 mb 440 mb to 560 mb 560 mb to 680 mb 680 mb to 800 mb 800 mb to surface (7) PCLD mb Cloud top pressure * (8) TCLD K Cloud top temperature * (9) ZANGLE deg Effective satellite zenith angle defined as the arccosine of the average value of the cosines of the individual satellite zenith angles (10) TIME hrs Time of observation in Z hours (HH.hh) (11) QFLAG Coarse indicator of agreement between observed and computed brightness temperatues for the sounding - 0 (best) to 3 (accepted but not as good) (12) TOZ D.U. Total ozone index (1 Dobson Unit=1 matm-cm) * (13) OLR W/m^2 Outgoing longwave radiation (14) LCRF W/m^2 Longwave cloud radiative forcing defined as the difference between the cloudy and clear sky OLR (15) PRECIP mm/day Precipitation estimate * (16) SPHUM g/kg Specific humidity values at 1000, 850, 700, 500, and 300 mb (17) PSURF mb Ancillary field -- forecast surface pressure The '*' indicates that these derived parameters were designated as experimental by the TOVS Implementation Team, pending further validation of the results. Items (1), (2), (3), (6), and (16) are stored as 3-dimensional SDSs where x=longitude, y=latitude and z=pressure altitude. All other items are stored as 2-dimensional SDSs in latitude and longitude. There is a total of 51 SDSs in each TOVS HDF file. The first group of 17 SDSs contain the parameter means, the second group of 17 the parameter standard deviations, and the final group of 17 the associated counts. Associated with each SDS is a set of ASCII labels containing the name, units, display format, and a brief description of the data in that array. The axes scales for each dimension of the SDS are also stored in the same representation as that used for the data, i.e., if the data are represented as 16-bit integers, then the scales are also stored as 16-bit integers. This number type, as well as the other information described above, is accessible via the HDF command line utilities (see section 4.2 and the example in Appendix A). For the TOVS data, the x-axis scales refer to longitude, the y-axis scales to latitude, and (for 3-dimensional SDSs) the z-axis scales to pressure altitude. It should be noted that in the case of layer quantities such as CLTEMP and FCLDP, the values for the z-axis scales denote the midpoints of the layers rather than the upper or lower boundaries. It should also be noted that the z-axis scale value associated with temperature at the surface (see TEMP above) is given a dummy value of "8888", since the surface pressure as defined in SDS #17 (PSURF) is itself variable over the entire grid. There are 6 level 3 data product files, each representing a different averaging time period. The spatial and temporal resolutions of the data are listed below: Averaging periods : daily, 5-day and monthly AM (descending nodes) daily, 5-day and monthly PM (ascending nodes) Gridbox dimensions : 1 degree latitude by 1 degree longitude Center of gridbox 1 : (-179.5,-89.5), with negative longitudes west of the Greenwich meridian Gridbox progression : proceeds from (-179.5,-89.5) to (179.5,-89.5), continuing northward and ending at the gridbox with central coordinates (179.5,89.5) An HDF file identifier has been included with each of the 6 files which indicates the type of data set, the satellite, the time period and the date pertaining to the data. This label takes the following form (using March 1988 AM as an example) : TOVS_NOAA10_PATHA_GLOBAL_GRIDDED_DAILY_AM_880320 (daily) TOVS_NOAA10_PATHA_GLOBAL_GRIDDED_5DAYS_AM_B880317.E880321 (5day) TOVS_NOAA10_PATHA_GLOBAL_GRIDDED_MONTHLY_AM_8803 (monthly) The HDF file identifiers for the PM files are named in an analagous manner. There are also three HDF ASCII annotations in each file. The first contains a general file description containing useful information related to the contents of the file and the Path A methodology. The second contains a short list of ASCII keywords (metadata) extracted by the Goddard DAAC as part of the archive process and used to populate a database for inventory purposes. The third HDF annotation contains auxiliary scientific data and statistics (science metadata) associated with the generation of the data contained in the SDSs. This is of interest only to expert users of the data requiring indepth knowledge of the special adjustments and corrections made by the algorithm during the retrieval process. Local equator crossing time for even numbered satellites such as NOAA-10 is nominally 7:30 PM for the ascending node and 7:30 AM for the descending node. For gridding purposes, the global AM (PM) map is not created by including data from all descending (ascending) portions of the orbits between 00Z and 24Z. This would result in data from 2 consecutive days being included in either map since the satellite crosses the date line during this 24-hour period. Rather, the gridding is based upon the local date and time of the orbits, e.g., only those ascending orbits with the same local day and time (which is always 7:30 PM) are used in the construction of the PM map. A similar procedure is used in the construction of the AM map. Each level 2 spot retrieval is assigned to a single gridbox according to which gridbox the spatial coordinates of the center of the level 2 FOV falls within. For a gridbox with multiple observations, a simple unweighted average of all points within the box is used for determining mean values. No interpolation or data filling is used. For all mean and standard deviation arrays, a fill of -999.99 is used to indicate that data for that gridbox is either missing, invalid or suspect. For the count arrays, a corresponding fill value of 0 is used under these circumstances. The quality flag QFLAG is assigned a value according to the following procedure: All retrievals are objectively validated according to the agreement between observed (cloud corrected) brightness temperatures for the temperature sounding channels and those computed from the solution. Two measures are used in this validation: the absolute difference between observed and computed brightness temperatures for MSU channel 2 and the root mean square difference between observed and computed brightness temperatures for the remainder of the temperature sounding channels. If either value is greater than 1 degree, the retrieval is rejected and a fill value is written out for all parameters except those related to cloud properties, which are always computed and written out. If each difference is less than 1 degree, a quality flag indicator is then computed based on the sum of the two measures as follows : QFLAG = ( | resid | + | rms | ) * 2. A quality flag value less than 1.0 indicates that the overall disagreement was rather small and the retrieval is assumed to be of very good quality. Quality flag values between 1.0 and 3.0 indicate an increasing difference between the observed and computed MSU channel 2 brightness temperatures and/or a higher RMS error for the remainder of the temperature sounding channels. 4. DATA ACCESS INFORMATION TOVS Path A files are archived in the Goddard DAAC as standard UNIX compressed files. They can be ordered through the Goddard DAAC using procedures outlined in section 6. Files are named using the convention: File Name Size Size (compressed) --------- ---- ----------------- TOVS_DAILY_pp_yymmdd.HDF 29 MB 10 MB TOVS_5DAYS_pp_Byymmdd.Eyymmdd.HDF 29 MB 22 MB TOVS_MONTHLY_pp_yymm.HDF 29 MB 26 MB where "dd" denotes day of year, "mm" the month number, "yy" the year, and "pp" the AM or PM period. Since the files are compressed, the extension ".Z" is appended to the file names. 4.1 Getting Data To obtain data see Section 6. 4.2 Reading Tapes If you obtained data by FTP, please go to Section 4.3. Data are available on 4 mm (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 and a block size of 63.5 KB are used, which translates to a blocking factor of 127. Tapes may be requested in "dd" or "tar" file format. By default the data are archived and distributed in compressed format; however, they are available in uncompressed format by special request. 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. Files are compressed using the standard UNIX "compress", indicated by a ".Z" appended to the data file name. The same utility that was used to create the tape, "dd" or "tar", must be used to access the data. If compressed files are requested, the data are compressed before the "dd" or "tar" utility is executed. Therefore, compressed data should be uncompressed after copying it from tape to local disk. 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. Public domain software, lzw, is available to read UNIX compressed data format on VAX VMS. To read compressed data files, you must first use "vmstar" or the "copy" command to unload the data from tape. Then issue the "lzw" command. 4.3 Reading the TOVS HDF files 4.3.1 Obtaining the HDF application software The HDF application software is available at no cost from NCSA for a variety of platforms. This software consists of visualization tools that display the HDF SDS files (Collage), calling interfaces that let you read and write HDF files from within a FORTRAN or C program (the HDF3.2r4 or HDF3.3r2 libraries), and command line utilities that operate directly on HDF files (automatically created as part of HDF library installation). To obtain the HDF library, log into the NCSA anonymous ftp server using the command: ftp opus.ncsa.uiuc.edu followed by > user > anonymous (as the user name) > (as the password) > cd /pub/dist/HDF > get README > quit (to exit and return to your local host) Review the README file for complete information concerning the the organization of the FTP directories and the procedure you should follow to download additional information and software, as well as locations of HDF software for your particular computer. A sample session which illustrates how to extract information from a TOVS Path A HDF file using the command line utility 'hdfed' (automatically created upon installation of the HDF software) is shown in the Appendix. 4.3.2 DAAC software for accessing TOVS data There are 2 FORTRAN programs developed by the DAAC, "tovs_hdflist" and "tovs_hdfdump", that can be used to read the data in the TOVS HDF files. These programs were designed and tested on SGI UNIX workstations only, but it should be quite easy to modify the FORTRAN code for use on other UNIX workstations as well as on VAX/VMS machines. The HDF calling interface library must be installed on your machine and linked to these programs during compilation. A brief description of the routines follows: (a) tovs_hdflist: This routine allows you to list all of the descriptive information associated with each SDS in the file, then select a particular SDS and extract spatial subsets of the data. The output will be in ASCII tabular format which can be printed either to the user's terminal or to an output file. (b) tovs_hdfdump: This routine performs a simple dump of all SDS attributes one at a time, displaying the actual science data in ASCII as a spatially subsampled data array (every 30th gridpoint in longitude, every 7th gridpoint in latitude). The output can be directed either to the terminal or a disk file. The full SDS data arrays are nonetheless read into memory, and the user can perform simple modifications to the source code to direct these data to a binary file. The FORTRAN source code is available via FTP from the Goddard DAAC online system by request via the Document/Software List screen under the Options menu. The routines are distributed as a single tar file. To receive the software, log into the DAAC online system and request the item TOVS L3 READ PROGRAMS from the Document/Software screen (see section 6). To use the software, consult the documentation file that is automatically included with the tar file. 4.3.3 Image Display and Analysis Tools The National Center for Supercomputing Applications (NCSA) provides several software packages which can be used to view HDF SDS data sets. Collage and XCollage for the Macintosh and UNIX workstations, and Image for the Macintosh are such packages. To obtain the Collage and Image software, log into the NCSA anonymous FTP server as described in section 4.2.1. Log into the Collage directory for Collage or the Mac/Image directory for Image using the command cd Collage or cd Mac/Image and download the files to your workstation using the FTP "get" or "mget" command. Then follow the instructions for installation and unpacking in the README files. In addition, a visualization package called VISTAS has been developed by a group at JPL and designed specifically for use with the level 3 TOVS Pathfinder data. VISTAS allows users to "navigate" the data by specifying which parameters they would like to visually examine on a certain date. They will be able to perform basic image processing functions and animation capabilities that make use of zooming and scrolling around the data set. Enhancements are planned in later releases of VISTAS. Currently, VISTAS runs on Sun Sparc Stations using Sun Operating Systems (OS) 4.1.x and on Silicon Graphics Workstations using IRIX 5.1.x. To obtain VISTAS, log into the Goddard DAAC anonymous ftp using: ftp daac.gsfc.nasa.gov or ftp 192.107.190.139 Then type the command: cd /pub/tovs/vistas and obtain the README for VISTAS by typing: get VISTAS.README_FIRST After obtaining the README, log out of anonymous ftp and consult the README for a detailed description on obtaining, installing and getting help on VISTAS. Please refer to section 6 of this document for a list of contacts for VISTAS software and user support. Some other public domain and commercial software packages can be used to view HDF data. They are: EASI/PACE, IDL, and SpyGlass (to obtain these, see Section 6). Thus far only IDL has been tested by the DAAC for reading and visualizing the TOVS Pathfinder files. 5. REFERENCES "Information on the GSFC Distributed Active Archive Center" February 1993, available from the Goddard DAAC. Kidwell, K., 1991, "NOAA Polar Orbiter Data User's Guide, NCDC/SDSD, National Climate Data Center, Washington, D.C. Takacs, L., A. Molod, and T. Wang, 1994, "Documentation of the Goddard Earth Observing System (GEOS) General Circulation Model Version 1", NASA Technical Memorandum 104606, April 1994. Susskind, J., J. Rosenfield, D. Reuter, and M. T. Chahine, 1984, "Remote Sensing of Weather and Climate Parameters from HIRS2/MSU on TIROS-N," J. Geophys. Res., 89D, 4677-4697. 6. POINTS OF CONTACT Archive Information: The Goddard DAAC Information Management System (IMS) provides online search and order capabilities for the TOVS and other data sets. The system is open to the public, but access to certain restricted products requires special authorization. Follow the instructions below to connect to the GSFC DAAC computer via TCP/IP protocol (Internet): 1) Type the following command from your computer connected to the Internet: telnet daac.gsfc.nasa.gov If the message HOST UNKNOWN appears, use the direct TCP/IP address 192.107.190.139. You should receive the message "Connected to daac.gsfc.nasa.gov". 2) After you have connected to the GSFC DAAC computer, you will be prompted to log onto the system. Enter the following username and password: Username: daacims Password: gsfcdaac A series of informational messages will be displayed followed by a user registration screen and the actual data system menu screens. For more information on the GSFC DAAC system capabilities and supported data sets, contact our User Services Office at: GSFC DAAC User Services Office Code 902.2 NASA/Goddard Space Flight Center Greenbelt, MD 20771 phone: (301) 286-3209 fax: (301) 286-1775 email: daacuso@daac.gsfc.nasa.gov Data Producer Information: Dr Joel Susskind NASA/Goddard Space Flight Center Code 910.4 Building 22, Room G2 Greenbelt, MD 20771 phone: (301) 286-7210 fax: (301) 286-1757 email: f41js@charney.gsfc.nasa.gov VISTAS Visualization Software Information: VISTAS software and documentation is available from the Goddard DAAC via anonymous ftp, but support for installation and use is provided by the Visualization and Earth Science Applications Group at JPL: Charles Thompson Mail Stop 168/522 Jet Propulsion Laboratory 4800 Oak Grove Dr. Pasadena, CA 91109 Phone: (818) 354-9602 Email: charles@tone.jpl.nasa.gov Kevin Hussey Mail Stop 168/522 Jet Propulsion Laboratory 4800 Oak Grove Drive Pasadena, CA 91109 Phone: (818) 354 4016 Kevin_Hussey@iplmail.jpl.nasa.gov Commercial Software Information: PCI Remote Sensing Corp. (EASI/PACE) 1925 N. Lynn Street, Suite 803 Arlington, VA 22209 Phone: (703) 243-3700, Fax: (703) 243-3705 Email: support@pci.on.ca (Internet) Research Systems, Inc. (IDL) 2995 Wilderness Place Boulder, CO 80301 Phone: (303) 786-9900, Fax: (303) 786-9909 Email: info@rsinc.com or support@rsinc.com (Internet) SpyGlass Inc. (SpyGlass) 1800 Woodfield Drive Savoy, IL 61874 Phone: (217) 355-6000, Fax: (217) 355-8925 Email: support@spyglass.com (Internet) 7. DATA SET UPDATES The full 16 years of TOVS data (1979 through 1994) will be processed, archived and distributed by the Goddard DAAC beginning in FY95. At that time the NOAA-10 data from 4/87 through 11/88 will be reprocessed using a new version of the processing algorithm supplied by the Satellite Data Utilization Office at Goddard Space Flight Center. Level 2 spot-by-spot data and level 4 fields from the analysis will be archived at the DAAC in addition to the level 3 gridded data product described above. All data products will be in the HDF format. 8. MISCELLANEOUS It is obligatory that any publication or presentation that uses the TOVS Pathfinder data acknowledge the source. The requested form of acknowledgment for any publication in which the TOVS Pathfinder data are used is "Data used by the authors in this study include data produced through funding from the Earth Observing System Pathfinder Program of NASA's Mission to Planet Earth in cooperation with National Oceanic and Atmospheric Administration. The data were provided by the Earth Observing System Data and Information System (EOSDIS), Distributed Active Archive Center at Goddard Space Flight Center which archives, manages, and distributes this data set." APPENDIX A: Sample dump of TOVS Pathfinder Path A data using 'hdfed' This exercise assumes that you have installed the HDF library appropriate to your machine, and in doing so have the HDF command line utilities available for use. The session is initiated by typing "hdfed", which results in the prompt "hdfed>". This utility allows one to skip around the HDF file to extract the desired information using the HDF tag concept. Please refer to the HDF documentation available from NCSA for information on the use of the command line utilities. Comments have been added on the right side margin to aid in interpreting the user input and the hdfed output. hdfed> open TOVS_MONTHLY_PM_8811.HDF ------------>OPEN HDF FILE hdfed> info -all ------------>LIST HDF DATA (1) Version Descriptor : (Tag 30) Ref 1 OBJECTS IN FILE (2) Scientific Data : (Tag 702) Ref 2---- (3) Number type : (Tag 106) Ref 2 | (4) SciData description : (Tag 701) Ref 2 | (5) SciData labels : (Tag 704) Ref 2 | (6) SciData units : (Tag 705) Ref 2 | (7) SciData formats : (Tag 706) Ref 2 |----TEMP SDS DATA & (8) SciData scales : (Tag 703) Ref 2 | SUPPORTING INFO (9) SciData max/min : (Tag 707) Ref 2 | (10) Calibration information : (Tag 731) Ref 2 | (11) Links related to the data set : (Tag 710) Ref 2 | *(12) Numeric Data Group : (Tag 720) Ref 2 |<---HDF POINTER IS (13) Scientific Data Group : (Tag 700) Ref 2 | CURRENTLY HERE (14) Data Id Annotation : (Tag 105) Ref 3---- (15) File Identifier : (Tag 100) Ref 4---- (16) File Description : (Tag 101) Ref 5 |----FILE INFORMATION (17) File Description : (Tag 101) Ref 6 | (18) File Description : (Tag 101) Ref 7---- (19) Scientific Data : (Tag 702) Ref 8---- (20) Number type : (Tag 106) Ref 8 | (21) SciData description : (Tag 701) Ref 8 | (22) SciData labels : (Tag 704) Ref 8 | (23) SciData units : (Tag 705) Ref 8 | (24) SciData formats : (Tag 706) Ref 8 |----CLTEMP SDS DATA & (25) SciData scales : (Tag 703) Ref 8 | SUPPORTING INFO (26) SciData max/min : (Tag 707) Ref 8 | (27) Calibration information : (Tag 731) Ref 8 | (28) Links related to the data set : (Tag 710) Ref 8 | (29) Numeric Data Group : (Tag 720) Ref 8 | (30) Scientific Data Group : (Tag 700) Ref 8 | (31) Data Id Annotation : (Tag 105) Ref 9---- . . . . . ( 48 ADDITIONAL SDS'S ) . . . (624) Scientific Data : (Tag 702) Ref 106-- (625) Number type : (Tag 106) Ref 106 | (626) SciData description : (Tag 701) Ref 106 | (627) SciData labels : (Tag 704) Ref 106 | (628) SciData units : (Tag 705) Ref 106 |---PSURF_CNT SDS (629) SciData formats : (Tag 706) Ref 106 | DATA & SUPPORTING (630) SciData scales : (Tag 703) Ref 106 | INFO (631) SciData max/min : (Tag 707) Ref 106 | (632) Calibration information : (Tag 731) Ref 106 | (633) Numeric Data Group : (Tag 720) Ref 106 | (634) Data Id Annotation : (Tag 105) Ref 107-- hdfed> next tag=100 ------>POINT TO ITEM 15 hdfed> dump -asc ------>DUMP FILE ID 0: TOVS_NOAA10_PATHA_GLOBAL_GRIDDED_MONTHLY_ 41: PM_8811 hdfed> next tag=101 ------>POINT TO ITEM 16 hdfed> dump -asc ------>DUMP FILE DESC. 0: This data set contains the TOVS level 41: 3 geophysical parameters derived 82: using the physical retrieval method of 123: Susskind et al. and processed by 164: the Satellite Data Utilization Office of 205: the Goddard Laboratory for At 246: mospheres at NASA/GSFC. This method, whi 287: ch is hydrodynamic model- and a pr 328: iori data-dependent, is designated as the 369: Path A scheme by the TOVS P 410: athfinder Science Working Group. The sys 451: tem steps through an interact 492: ive forecast-retrieval-analysis cycle, wh 533: ereby in each 6 hour synoptic p 574: eriod, the 6 hour forecast fields of temp 615: erature, humidity and surface pres 656: sure generated by the GLA GCM are used as 697: the first guess for all 738: soundings occuring within a 6 hour time w 779: indow centered upon the forecas 820: t time. For the Pathfinder data set perio 861: d, only NOAA-10 sounding d 902: ata are used. These retrievals are then 943: combined with all available i 984: n situ measurements in the 6 hour interva 1025: l using an optimal interpolation 1066: (OI) analysis scheme. This analysis is t 1107: hen used to specify the initial c 1148: onditions for the next 6 hour forecast. . . ( MORE TEXT FOLLOWS) . . hdfed> prev tag=106 ------>POINT TO ITEM 3 hdfed> dump -byte ------>DUMP NUMBER TYPE 0: 1 5 32 1 5 ==>32 BIT FLOAT hdfed> next tag=704 ------>POINT TO ITEM 5 hdfed> dump -asc ------>DUMP DATA & SCALE 0: TEMP pressure latitude longitude LABELS hdfed> next tag=705 ------>POINT TO ITEM 6 hdfed> dump -asc ------>DUMP DATA & SCALE 0: degrees K millibars degrees degrees UNITS hdfed> next tag=706 ------>POINT TO ITEM 7 hdfed> dump -asc ------>DUMP DATA & SCALE 0: f6.1 f5.0 f6.1 f6.1 DISPLAY FORMAT hdfed> next tag=707 ------>POINT TO ITEM 9 hdfed> dump -float ------>DUMP DATA MAX/MIN 0: 3.085836e+02 1.880010e+02 VALUES hdfed> next tag=105 ------>POINT TO ITEM 14 hdfed> dump -asc ------>DUMP DATA DESC. 0: Vertical temp profile at levels: sur 41: f(8888),1000,850,700,500,400,300,200,100, 82: 70,50, & 30 mb 123: hdfed> prev tag=702 ------>POINT TO ITEM 19 hdfed> dump -float ------>DUMP DATA . . . . . . . . . (ONLY A SHORT EXTRACT SHOWN HERE) . . . . . . . . . 8800: 2.558580e+02 2.601211e+02 2.580414e+02 2.623552e+02 8816: 2.580495e+02 2.615204e+02 2.567600e+02 2.587131e+02 8832: 2.590164e+02 2.583955e+02 2.579311e+02 2.594531e+02 8848: 2.563615e+02 2.548486e+02 2.553858e+02 2.565701e+02 8864: 2.539682e+02 2.563604e+02 2.560714e+02 2.551103e+02 8880: 2.507568e+02 2.535053e+02 2.531571e+02 2.542865e+02 8896: 2.539790e+02 2.529429e+02 2.517126e+02 2.517452e+02 8912: 2.508007e+02 2.518857e+02 2.481319e+02 2.495843e+02 8928: 2.512309e+02 2.496174e+02 2.461953e+02 2.518858e+02 8944: 2.458743e+02 2.479747e+02 2.486914e+02 2.502587e+02 8960: 2.474468e+02 2.458264e+02 2.468604e+02 2.479645e+02 8976: 2.491878e+02 2.484749e+02 2.481041e+02 2.467125e+02 8992: 2.468461e+02 2.496946e+02 2.476380e+02 2.469035e+02 9008: 2.481391e+02 2.468717e+02 2.467680e+02 2.483007e+02 9024: 2.489336e+02 2.483130e+02 2.494991e+02 2.503108e+02 9040: 2.473857e+02 2.480916e+02 2.503401e+02 2.489309e+02 9056: 2.507190e+02 2.510516e+02 2.510123e+02 2.489313e+02 9072: 2.484615e+02 2.501847e+02 2.501460e+02 2.517592e+02 9088: 2.512978e+02 2.502234e+02 2.500982e+02 2.510085e+02 9104: 2.510705e+02 2.490730e+02 2.485877e+02 2.473113e+02 9120: 2.482688e+02 2.483945e+02 2.494114e+02 2.521082e+02 9136: 2.508052e+02 2.505715e+02 2.480922e+02 2.501101e+02 9152: 2.502212e+02 2.516725e+02 2.504512e+02 2.517451e+02 9168: 2.479705e+02 2.470316e+02 2.493798e+02 2.486326e+02 9184: 2.493004e+02 2.464729e+02 2.465587e+02 2.508984e+02 9200: 2.468885e+02 2.431548e+02 2.471116e+02 2.486381e+02 . . . . . . . . . . . . hdfed> next tag=106 ref=106 ------>POINT TO LAST SDS hdfed> dump -byte ------>DUMP NUMBER TYPE 0: 1 22 16 1 22 ==>16 BIT INT hdfed> next tag=704 ------>POINT TO ITEM 627 hdfed> dump -asc ------>DUMP DATA & SCALE 0: PSURF_COUNT latitude longitude LABELS hdfed> next tag=705 ------>POINT TO ITEM 628 hdfed> dump -asc ------>DUMP DATA & SCALE 0: degrees degrees UNITS hdfed> next tag=706 ------>POINT TO ITEM 629 hdfed> dump -asc ------>DUMP DATA & SCALE 0: i4 i7 i7 DISPLAY FORMAT hdfed> next tag=707 ------>POINT TO ITEM 631 hdfed> dump -short ------>DUMP DATA MAX/MIN 0: 61 1 VALUES hdfed> next tag=105 ------>POINT TO ITEM 634 hdfed> dump -asc ------>DUMP DATA DESC. 0: Gridbox counts for forecast surface p 41: ressure 82: 123: hdfed> prev tag=702 ------>POINT TO ITEM 624 hdfed> dump -short ------>DUMP DATA . . . . . . . . . (ONLY A SHORT EXTRACT SHOWN HERE) . . . . . . . . . 9084: 4 5 1 5 6 4 9096: 5 7 5 12 9 9 9108: 3 6 6 11 2 9 9120: 5 14 17 15 14 22 9132: 13 14 21 18 17 27 9144: 19 6 10 13 11 19 9156: 10 15 14 18 13 13 9168: 13 15 9 10 12 9 9180: 9 7 4 1 6 4 9192: 3 4 5 5 2 5 9204: 2 3 4 4 6 11 9216: 2 7 9 4 4 4 9228: 1 8 8 7 3 12 9240: 7 9 7 10 10 7 9252: 5 8 3 6 7 8 9264: 6 9 4 8 7 5 9276: 7 8 5 5 9 8 9288: 8 4 10 5 10 13 9300: 11 4 15 12 12 13 9312: 21 13 11 12 18 23 9324: 15 23 18 25 26 23 9336: 25 24 30 20 18 13 9348: 20 24 23 28 28 26 9360: 30 34 35 26 39 31 . . . . . . . . . . . . hdfed> quit ------->END hdfed SESSION