The GPROF 6.0 data set contains 5-day (pentad) averages of precipitation rate from the GPROF 6.0 Gridded Orbits product. The GPROF (Goddard Profiling Algorithm) data set contains a suite of nine products providing instantaneous gridded values of precipitation totals for each granule of the SSM/I (Special Sensor Microwave/Imager) data over the roughly 14-year period from July 1987 through the present. Even though there have been at least two satellites for the entire period, sampling is sufficiently sparse that the data are averaged for pentads, and then the pentads are smoothed with a 1-2-3-2-1 time-weighting.
The data set prepared for SAFARI covers the years 1999, 2000, and 2001. The data files are stored as annual files of pentad (5-day) images. The pentads are stored in band sequential [BSQ] format (one image after the other) within the yearly files.
More information about the sensor, product subsetting, pentad numbering, and data quality can be found in the companion file S2K_precip_gprofv6.pdf.
Cite this data set as follows:
Nelkin, E. J., G. J. Huffman, and C. D. Kummerow. 2004. SAFARI 2000 SSM/I GPROF 6.0 Precipitation Data, 0.5-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/716.
Kummerow, C., W. S. Olson, and L. Giglio. 1996. A simplified scheme for obtaining precipitation and vertical hydrometeor profiles from passive microwave sensors. IEEE Trans. Geosci. Remote Sens. 34: 1213-1232.
Olson, W. S., C. D. Kummerow, Y. Hong, and W.-K. Tao. 1999. Atmospheric latent heating distributions in the tropics derived from satellite passive microwave radiometer measurements. J. Appl. Meteor. 38: 633-664.
The data files are stored as annual files of pentad (5-day) images. The pentads are stored in band sequential [BSQ] format (one image after the other) within the yearly files. 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 0.5 degree by 0.5 degree GPROF V6 data were provided by David Nelkin of the GSFC Mesoscale Atmospheric Processes Branch. The global half-degree images provided were 720 sample by 360 line 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 321, starting line 161, with a size of 142 samples by 122 lines. Each image pixel is stored as a 4-byte real value of precipitation rate in units of millimeters/hour. The data set prepared for SAFARI covers the years 1999, 2000, and 2001.
The images provided here are subsets 142 samples by 122 lines in size that were extracted from the global images. Each half-degree image pixel is stored as a 4-byte real value and the units are mm/day. The data set prepared for SAFARI covers the years 1999, 2000, and 2001.
??? appears to be discrepancy between last two sections regarding units -- mm/hr or mm/day ??? Companion has mm/hr.