Africa RFE General Description
As of January 1, 2001, RFE version 2.0 has been implemented by NOAA's
Climate Prediction Center. Created by Ping-Ping Xie, this replaces
RFE 1.0, the previous rainfall estimation algorithm that was operational from 1995 through 2000 (Herman et al., 1997). RFE 2.0 uses additional techniques to better estimate precipitation while continuing the use of cloud top temperature and station rainfall data that formed the basis of RFE 1.0. Meteosat 7 geostationary satellite infrared data is acquired in 30-minute intervals, and areas depicting cloud top temperatures of less than 235K are used to estimate convective rainfall. WMO Global Telecommunication System (GTS) data taken from ~1000 stations provide accurate rainfall totals, and are assumed to be the true rainfall near each station. RFE 1.0 used an interpolation method to combine Meteosat and GTS data for daily precipitation estimates, and warm cloud information
was included to obtain dekadal estimates. The two new satellite rainfall estimation
instruments that are incorporated into RFE 2.0 are the Special Sensor
Microwave/Imager (SSM/I) on board Defense Meteorological Satellite
Program satellites, and the Advanced Microwave Sounding Unit (AMSU).
Both estimates are acquired at 6-hour intervals and have a resolution
of 0.25 degrees. RFE 2.0 obtains the final daily rainfall estimation
using a two part merging process, then sums daily totals to produce
dekadal estimates. All satellite data is first combined using a
maximum likelihood estimation method, and then GTS station data is
used to remove bias. Warm cloud precipitation estimates are not
included in RFE 2.0.