The ISCCP DX images and flux data are online and can be obtained from the NASA GSFC DAAC via ftp from daac.gsfc.nasa.gov in subdirectory pub/toga_coare/satellite/isccp/ or via the WWW using the URL ... http://disc.gsfc.nasa.gov/fieldexp/TOGA/sat_link.shtml . To obtain the ISCCP data on tape, contact the DAAC User Services Office. For help with NASA TOGA COARE data residing at the GSFC DAAC, contact Pat Hrubiak at email@example.com.
TOGA COARE was a multidisciplinary, international research effort that investigated the scientific phenomena associated with the interaction between the atmosphere and the ocean in the warm pool region of the western Pacific. The field experiment phase of the program took place from 1 November 1992 through 28 February 1993 and involved the deployment of oceanographic ships and buoys, several ship and land based Doppler radars, multiple low and high level aircraft equipped with Doppler radar and other airborne sensors, as well as a variety of surface based instruments for in situ observations.
The NASA component of TOGA COARE, while contributing directly to overall COARE objectives, emphasized scientific objectives associated with the Tropical Rainfall Measuring Mission (TRMM) and NASA's cloud and radiation program.
The ISCCP DX and flux dataset consists of analyses of data acquired from the GMS satellite and the NOAA 11 and 12 satellites in support of TOGA-COARE. Principal Investigator Bill Rossow of the Goddard Institute for Space Studies (GISS) subsetted this dataset both temporally and spatially to conform to the TOGA COARE period and region.
Temporal Coverage and Resolution: All times are in GMT. The temporal coverage for the TOGA COARE campaign and for this ISCCP subset is 4 months from 1 November 1992 through 28 February 1993. The sampling interval for these data is about 3 hr for GMS and 12 hr for each NOAA polar orbiter.
Spatial Coverage and Resolution: The ISCCP subsets for the TOGA COARE campaign cover the region: Longitude: 120E --> 190E Latitude: 20S --> 20N The spatial resolution is about 30 km for sensors on all 3 satellites.
ISCCP SCIENCE OBJECTIVES
Investigation of the role of clouds in climate involves a complex interrelated study of many different processes and addresses many different questions. The ISCCP's scientific objectives are:
- to produce a global, reduced resolution, infrared and visible, calibrated and normalized radiance dataset containing basic information on the radiative properties of the atmosphere from which cloud parameters can be derived; - to stimulate and coordinate basic research on techniques for inferring the physical properties of clouds from the condensed radiance dataset and to apply the resulting algorithms to derive and validate a global cloud climatology for improving the parameterization of clouds in climate models; -to promote research using ISCCP data and contribute to improved understanding of the Earth's radiation budget (top of atmosphere and surface) and hydrological cycle.
General Description: This analysis is based on data from the GMS, NOAA 11 and NOAA 12 satellites;
GMS (Geostationary Meteorological Satellite): Operated by the Japan Meteorological Agency (JMA), GMS is a spin-stabilized spacecraft maintained at 140E longitude. Imaging data are from the Visible Infrared Spin-Scan Radiometer (VISSR), with high resolution (1.25 km) visible images obtained by four identical detectors scanning in parallel. The spin-scan is from west to east and from north to south.
The NOAA TIROS-N series satellites are three-axis stabilized in 850 KM (nominal) circular, near-polar, sun-synchronous orbits with an inclination angle of approximately 99 degrees (retrograde) to the equator. The orbital period is about 102 minutes. Sequential orbits observe adjacent longitudes near the equator and provide overlapping coverage in both polar regions. The instrument complement is as follows:
General Characteristics: ISCCP DX data are the individual pixel-level results of the analysis that contain the visible and IR radiances, the clear-sky radiances, the surface reflectance and temperature from the clear-sky radiances, the cloud detection decision, and the retrieved physical quantities. For clear pixels, these are the surface reflectance and temperature; for cloudy pixels these are the cloud top temperature/pressure and optical thickness. The cloud top temperature is obtained with three different models: assuming an opaque cloud (all times of day), assuming a liquid water cloud or an ice cloud (daytime).
The ISCCP DX TOGA COARE subset totals 2129 data files and is about approximately 1.07 GB in volume. Each file contains data for one GMT. Files are named 'FC_DT_KA.YYMMDDHH' where YY=92, 93 (year), MM=11, 12, 1, 2 (month), DD=01, 02,.., 31 (date) and HH=00, 03, .. 21 (GMT).
Data Format: Each data file comprises 448 (28 X 16) grid boxes, each containing 48 1792 byte records corresponding to the 48 parameters.
There are a variable number of data records in each DX image. Each record contains packed binary pixel data as follows:
I*4 IWEST Western-most longitude (0-3600 degrees*10) I*4 IEAST Eastern-most longitude (0-3600 degrees*10) I*4 INORTH Northern-most latitude (0-1800 degrees*10) I*4 ISOUTH Southern-most latitude (0-1800 degrees*10) I*4 NPIX Number of pixels I*4 IOUT Number of bytes in packed data BUFFER I*2 LONBUF(NPIX) Longitudes for NPIX pixels (0-3600 degrees*10) I*2 LATBUF(NPIX) Latitudes for NPIX pixels (0-1800 degrees*10) I*2 XBUF(NPIX) X-positions for NPIX pixels (1-1440) I*2 YBUF(NPIX) Y-positions for NPIX pixels (1-550) I*1 BUFFER(IOUT) Packed data for NPIX pixels remainder of record is filled with I*1 255 values.
The contents of the buffer as it is unpacked are as follows:
NOTE 1: Numbers on the left identify the byte number from 1 to 37. This is the MAXIMUM number of bytes that a pixel can have. Not all bytes are present for all pixels.
DATA SECTION 1 - pixel ident. satellite angle, IR cloud detection
1. NODAY,BXSHOR,LNDWTR,HITOPO,SNOICE,TIMSPA (N,B,L,H,SS,TT) *NODAY : BX day/night flag (0-1), 1 = day sect. 2,4 not present *BXSHOR : BX shore flag (0-1), 1 = shore pixel LNDWTR : Land/water flag (0-1), 1 = water pixel HITOPO : Topography flag (0-1), 1 = high topography pixel SNOICE : Snow/ice code (0-3) *TIMSPA : Time/space test result (0-3)
2. ICSLOG,BXITHR (IIIII,BBB) *ICSLOG : IR clear sky composite logic code (0-24) *BXITHR : BX IR threshold result ()-5)
3. MUE : Cosine of satellite angle * 100 (0-100)
4. IRAD : IR radiance (0-254 ct)
5.*BXICSR : BX IR clear sky radiance (0-254 ct) If image header says additional channels are present (BXADDL>0) then:
6. ARAD(1) : First additional channel radiance (0-254 ct)
7. ARAD(2) : Second additional channel radiance (0-254 ct)
8. ARAD(3) : Third additional channel radiance (0-254 ct)
DATA SECTION 2 - sun angles, VIS cloud detection if NODAY = 0 (day sections present) then:
9. GLINT,VCSLOG,BXVTHR (G,VVVV,BBB) GLINT : Glint flag (0-1), 1 = glint condition exists *VCSLOG : VIS clear sky composite logic code (0-14) *BXVTHR : BX VIS threshold result
10. MU0 : Cosine of sun angle * 100 (0-100)
11. PHI : Relative azimuth angle (0-180 degrees)
12. VRAD : VIS radiance (0-254 ct)
13.*BXVCSR : BX VIS clear sky radiance (0-254 ct)
DATA SECTION 3 - adjusted cloud detections, IR retrievals, additional channel cloud detections
14. DAYNIT,ITHR,VTHR,SHORE (D,III,VVV,S) DAYNIT : Day/night flag (0-1), 1 = night pixel (no VIS retrieval ITHR : IR threshold result (0-5) VTHR : VIS threshold result (0-5) SHORE : Shore flag (0-1), 1 = shore pixel
15. IRET,ICSRET (IIII,IIII) *IRET : IR retrieval code (0-12) *ICSRET : IR clear sky composite retrieval code (0-12)
16. ICSRAD : IR clear sky composite radiance (0-254 ct)
17. ITMP : IR retrieved cloud top or surface temperature (0-254 ct)
18. IPRS : IR retrieved cloud top pressure (0-254 ct)
19. ICSTMP : IR retrieved clear sky composite temperature (0-254 ct)
20. ICSPRS : IR retrieved clear sky composite pressure (0-254 ct) if image header says is polar (SATTYP = 1,2,or -3) then:
21. NREF : NI reflectivity (NOAA channel 3) (0-254 ct)
22. NTHR : NI threshold result (NOAA channel 3) (0-254 ct)
28. VTMP : VIS adjusted cloud top temperature (0-254 ct)
29. VPRS : VIS adjusted cloud top pressure (0-254 ct)
30. VTAUIC : VIS retrieved ice cloud tau (0-254 ct)
31. VTMPIC : VIS retrieved ice cloud top temperature (0-254 ct)
32. VPRSIC : VIS retrieved ice cloud top pressure (0-254 ct)
b) Flux data
General Characteristics: The ISCCP Flux TOGA COARE subset consists of 953 binary data files and is approximately 78.2 MB in volume. Files are named 'FC_DT_KA.YYMMDDHH' where YY=92, 93 (year), MM=11, 12, 1, 2 (month), DD=01, 02,.., 31 (date) and HH=00, 03, .. 21 (GMT).
Data Format: Each fixed-length data file is for one GMT and contains 48 1792-byte records, each corresponding to one of the following parameters, ordered here by direct access record numbers used in the read program:
(1) SW downwelling at TOA; (2) SW upwelling at TOA; (3) SW downwelling at SRF; (4) SW upwelling at SRF; (5) LW upwelling at TOA; (6) LW upwelling at SRF; (7) LW downwelling at SRF; (8) SW upwelling at TOA for 100% overcast; (9) SW downwelling at SRF for 100% overcast; (10) SW upwelling at SRF for 100% overcast; (11) LW upwelling at TOA for 100% overcast; (12) LW upwelling at SRF for 100% overcast; (13) LW downwelling at SRF for 100% overcast; (14) SW upwelling at TOA for clear sky; (15) SW downwelling at SRF for clear sky; (16) SW upwelling at SRF for clear sky; (17) LW upwelling at TOA for clear sky; (18) LW upwelling at SRF for clear sky; (19) LW downwelling at SRF for clear sky; (20) Cosine solar zenith angle (0 --> 1); (21) Cloud fraction (0 --> 1); (22) Cloud top T (K); (23) Cloud TAU; (24) Surface T (K); (25) Surface reflectance form D1/C2; (26) Actually used surface reflectance; (27) Surface air T (K); (28) Cloud top pressure (mb); (29) Cloud base pressure (mb); (30) Surface pressure (mb); (31) T at 900 mb; (32) T at 740 mb; (33) T at 620 mb; (34) T at 500 mb; (35) T at 375 mb; (36) T at 245 mb; (37) T at 115 mb; (38) Pressure of tropopause; (39) T at tropopause; (40) T at 50 mb of stratosphere; (41) T at 15 mb of stratosphere; (42) Precipitable water (cm) for layer of 900 mb; (43) Precipitable water (cm) for layer of 740 mb; (44) Precipitable water (cm) for layer of 620 mb; (45) Precipitable water (cm) for layer of 500 mb; (46) Precipitable water (cm) for layer of 375 mb; (47) Column ozone amount (Dobson); (48) Total precipitable water (cm) for all 5 tropospheric layers.
- for dx data: Fortran 77 program DXREAD.f was provided by the data producer to read the ISCCP DX files. This software is copiously documented and complete, except for output statements which should be supplied by the user to extract the desired parameters. It compiles and runs without modification on the DAAC's SGI equipment under IRIX 4.0.5C.
- for flux data: Fortran 77 code was provided by the data producer to read the ISCCP Flux data files.
NASA/Goddard Institute for Space Studies
Province or State:
NASA TOGA COARE Project Office, 1994: NASA/TOGA COARE Science Data Workshop II Proceedings, Albuquerque, New Mexico, March 15-17, 1994, NASA Langley Research Center, Mail Stop 483, Hampton, VA 23666, 4 pp.
National Environmental Satellite Data and Information Service (NESDIS), 1991: NOAA Polar Orbiter Data Users Guide, U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Climatic Data Center, Satellite Data Service Division.
TOGA COARE International Project Office (TCIPO), 1992: TOGA COARE Operations Plan, Working Version September 1992. University Corporation for Atmospheric Research, Boulder, CO 80307, 138 pp.
TOGA COARE International Project Office (TCIPO), 1993: TOGA COARE Intensive Observing Period Operations Summary. University Corporation for Atmospheric Research, Boulder, CO 80307, 505 pp.
TOGA COARE International Project Office (TCIPO), 1994: Summary Report of the TOGA COARE International Data Workshop, Toulouse, France, 2 - 11 August 1994, University Corporation for Atmospheric Research, Boulder, CO 80307, 170 pp.
Webster, P.J., and R. Lukas, 1992: TOGA COARE: The Coupled Ocean- Atmosphere Response Experiment. Bull. Am. Meteorol. Soc. 73, 1377-1416.
World Climate Research Programme (WCRP), 1985: Scientific Plan for the TOGA Coupled Ocean-Atmosphere Response Experiment. WCRP Publications Series, No. 3 Addendum, World Meteorological Organization, Geneva, 96 pp.
World Meteorological Organization (WMO), 1985: WMO/TD-No. 58: The International Satellite Cloud Climatology Project (ISCCP) Description of Reduced Resolution Radiance Data. (Revised August 1987), Geneva.
World Meteorological Organization (WMO), 1988: WMO/TD-No, 266: International Satellite Cloud Climatology Project (ISCCP) Documentation of Cloud Data, (Revised April 1991), Geneva.