For documentation on the ARC data set and how it differs from the RFE V2.0 operational data set, see the following web page: http://www.cpc.ncep.noaa.gov/products/fews/AFR_CLIM/afr_clim.html
and the following CPC document: RFE Climatology Paper for 2004 AMS Conference on Applied Climatology.
The following information is excerpted from the "readme" file associated with this data set:
This is the readme file for daily NOAA/Climate Prediction Center's Africa Rainfall Climatology (ARC) files. There are a few missing days within this Jan 1995-Present dataset. This is due to either bad GTS rain gauge observations or bad raw Meteosat IR temperature data. For information about data methodology or other questions, see: http://www.cpc.ncep.noaa.gov/products/fews/AFR_CLIM/afr_clim.html or contact: Timothy Love 301-763-8000 x7549 tim.love@noaa.gov ------------------------------------------------------------------------------ Each day of data corresponds to the 24 hour temporal domain of 0600Z day 1 until 0530Z day +1. Spatial domain covers the entire Africa continent from 20.0W-55.0E and 40.0S-40.0N at a resolution of 0.1 degrees. Each file is in binary format with a single record. Created on a HPUX workstation, files are in 4-byte big_endian format and thus must be byteswapped if reading on a little_endian machine (Linux, SGI, x86 pc). File structure is a 751x801 array (constant 0.1 degree resolution) of floating point precipitation estimate values. Pixel 1,1 corresponds with the geographic coordinate of 20.0W,40.0S. Pixel 2,1 is 19.9W,40.0S. Pixel 751,801 is 55.0E,40.0S. Moving northward a tenth of degree, pixel 1,2 is 20.0W,39.9S. And so on. The final pixel in each file array is thus 751,801 = 55.0E,40.0N. Uncompressed file size: 2406204 bytes = 4 bytes/pixel * 751 lon points * 801 lat points For a GrADS control or GIS header file, contact me and I'll gladly set you up.