The Global Precipitation Climatology Project (GPCP) is an international project designed to provide improved long-record estimates of precipitation over the globe. The general approach is to combine the precipitation information available from several sources into a final merged product that takes advantage of the strengths of each data type. The GPCP has promoted the development of an analysis procedure for blending the various estimates together to produce the necessary global gridded precipitation fields. The currently operational procedure is based on Huffman et al. (1995) and has been used to produce the GPCP Version 2 Combined Precipitation Data Set, covering the period January 1979 through 2002. The primary product in the Version 2 data set is a combined observation-only data set, that is, a gridded analysis based on gauge measurements and satellite estimates of rainfall. Beginning in October 1996, the GPCP began producing 3-hourly merged global infrared (IR) brightness temperature (Tb) histograms on a 1-degree by 1-degree grid, which became the impetus for this product, also known as the 1-degree daily (1DD) product.
The data set prepared for SAFARI 2000 was extracted from the 1DD data set for the years 1999, 2000, and 2001.
The GPCP is an element of the Global Energy and Water Cycle Experiment (GEWEX) of the World Climate Research program (WCRP). The 1DD is produced by the GPCP Merge Development Centre (GMDC), located at NASA's Goddard Space Flight Center in the Laboratory for Atmospheres.
More information about the SAFARI data product is contained in the on-line companion file GPCP_Daily_Precipitation.pdf. News of recent updates to the GPCP data set of daily global gridded values of precipitation totals is described in the on-line companion file GPCP_1DD_doc.pdf.
Cite this data set as follows:
Huffman, George J., R. F. Adler, and D. T. Bolvin. 2004. SAFARI 2000 GPCP Daily 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/712.
Huffman, G. J., R. F. Adler, P. A. Arkin, A. Chang, R. Ferraro, A. Gruber, J. J. Janowiak, R. J. Joyce, A. McNab, B. Rudolf, U. Schneider, and P. Xie. 1997. The Global Precipitation Climatology Project (GPCP) Combined PrecipitationData Set. Bull. Amer. Meteor. Soc. 78: 5-20.
Huffman, G. J., R. F. Adler, M. M. Morrissey, S. Curtis, R. Joyce, B. McGavock, and J. Susskind. 2001. Global precipitation at one-degree daily resolution from multi-satellite observations. J. Hydrometeor. 2: 36-50.
Susskind, J., P. Piraino, L. Rokke, L. Iredell, and A. Mehta. 1997. Characteristics of the TOVS Pathfinder Path A Dataset. Bull. Amer. Meteor. Soc. 78: 1449-1472.
Wentz, F. J., and R. W. Spencer. 1998. SSM/I rain retrievals within a unified all-weather ocean algorithm. J. Atmos. Sci. 55: 1613-1627.
The data files are stored as monthly files of daily images. The daily images are stored in a band sequential [BSQ] binary format (one after the other) within the monthly files. The files for each month vary in size depending upon the number of days in the month (28, 29, 30, or 31). 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. More information about the data file format is contained in the companion file GPCP_Daily_Precipitation.pdf.