The purpose of the Tropical Rainfall Measuring Mission (TRMM) and TRMM Product 3B-43 is to provide a monthly, best-estimate precipitation rate and root-mean-square (RMS) precipitation error. These gridded estimates are on a one-calendar month temporal resolution and a 1-degree by 1-degree spatial resolution for the global band extending from 40 degrees south to 40 degrees north latitude. Product 3B-43 combines two independent precipitation estimates, the daily-average adjusted GOES Precipitation Index (GPI) based on merged-infrared (IR) estimates (TRMM Product 3B-42) and the monthly accumulated Climate Assessment and Monitoring System (CAMS) or Global Precipitation Climatology Centre (GPCC) rain gauge analysis (TRMM Products 3A-45A and 3B-45B, respectively). During initial processing the CAMS data are used. During reprocessing, the GPCC data are used.
The data set prepared for SAFARI covers the years 1999, 2000, and 2001. The data files are stored as yearly files of monthly images. The monthly images are stored in a band sequential [BSQ] format (one image after the other) within the yearly files. The files for each year thus contain 12 monthly images per file. The Product 3B-43 Users Guide is included as a companion file 3B43_Users_Guide.pdf.
Cite this data set as follows:
Huffman, G. J., and D. Bolvin. 2004. SAFARI 2000 TRMM 3B-43 Monthly Precipitation, 1-Deg, 1999-2001. Data set. Available on-line [http://www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/718.
Huffman, G. J., R. F. Adler, B. Rudolf, U. Schneider, and P. R. Keehn. 1995. Global precipitation estimates based on a technique for combining satellite-based estimates, rain gauge analysis, and NWP model precipitation information. J. Climate 8: 1284-1295.
Huffman, G. J. 1997. Estimates of Root-Mean-Square Random Error for Finite Samples of Estimated Precipitation. J. Appl. Meteor., 1191-1201.
Huffman, G. J., R. F. Adler, P. Arkin, A. Chang, R. Ferraro, A. Gruber, J. Janowiak, A. McNab, B. Rudolph, and U. Schneider. 1997. The Global Precipitation Climatology Project (GPCP) Combined Precipitation Dataset. Bul. Amer. Meteor. Soc. 78: 5-20.
The data files are stored as yearly files of monthly images. The monthly images are stored in a band sequential [BSQ] format (one image after the other) within the yearly files. The files for each year thus contain 12 monthly images per file. There may be some trailing bytes at the end of the monthly files. These are an artifact of the image processing system that produced the files and can be ignored.
The annual files of 3B-43 data were provided by David Bolvin of the GSFC Mesoscale Atmospheric Processes Branch in a flat binary format. The global images were 360 sample by 180 line Real*4 images. The files were oriented with an upper left corner of 90 degrees North at the Prime Meridian. The yearly files were ingested into the PCI image processing package, where the Eastern and Western Hemispheres were switched so that the Prime Meridian was at the center of the images. Southern Africa subsets were then extracted from the global images at starting sample 161, starting line 81, with a size of 71 samples by 61 lines. Each image pixel is stored as a 4-byte real value of precipitation rate in units of millimeters. The data set prepared for SAFARI covers the years 1999, 2000, and 2001. Note that although the subset extraction extends to 50 degrees south for consistency, the 3B-43 data within the extractions extend only as far as 40 degrees south.
Additional data file and image information are available in the companion file 3B43_Users_Guide.pdf.
NOTE: TRMM Version 6 Reprocessing Will Start On April 1, 2004
Beginning April 1, 2004, Version 6 algorithms will be used to process incoming TRMM data. Concurrently, existing TRMM data will be reprocessed back to the start of the mission using the Version 6 science algorithms. The TRMM Version 6 data are expected to be available at the GES DISC DAAC sometime in May 2004.