GIRAFE v1: CM SAF Global Interpolated RAinFall Estimation version 1

The GIRAFE v1 climate data record (CDR) provides precipitation estimates derived from a
combination of passive microwave (PMW) observations onboard polar orbiting satellites and
infrared (IR) observations onboard geostationary satellites. GIRAFE v1 covers the time period
2002/01/01 until 2022/12/31. The PMW input to GIRAFE v1 is from various microwave imager and
sounder instruments. Precipitation rate estimates are retrieved from the observed PMW
brightness temperatures by precipitation retrieval algorithms HOAPS, PNPR-CLIM, and PRPS. The
resulting archives of instantaneous precipitation rate estimates are homogenized using
quantile mapping. The IR input to GIRAFE comes from the five geostationary positions forming
the Geo-Ring, providing observations along all geographical longitudes. The spatially and
temporally highly resolved IR input is trained to detect the occurrence of precipitation
using the PMW-based instantaneous precipitation rate estimates. Conditional precipitation
rates are computed based on PMW observations only. At latitudes higher than 55°N/S where
Geo-Ring IR pixels are extremely distorted, GIRAFE v1 relies only on the PMW input. GIRAFE v1
is a gridded product which is available globally at a spatial resolution of 1° x 1°
and at a temporal resolution of 24 h as accumulated precipitation computed from the (IR-based)
fraction of precipitation and the conditional precipitation rate. Additionally, 1° x
1° monthly mean values of the daily accumulated precipitation are provided. The daily
accumulated precipitation features a dedicated sampling uncertainty at the same 1° x
1° x 24 h resolution which is based on the analysis of decorrelation scales in space and
time in the IR-based precipitation fields.