Global Precipitation Climatology
One of the major goals of GPCP is to develop a more complete
understanding of the spatial and temporal patterns of global precipitation. Data from over
6,000 rain gauge stations, and satellite geostationary and low-orbit infrared, passive
microwave, and sounding observations have been merged to estimate monthly rainfall on a
2.5-degree global grid from 1979 to the present. The careful combination of
satellite-based rainfall estimates provides the most complete analysis of rainfall
available to date over the global oceans, and adds necessary spatial detail to the
rainfall analyses over land. In addition to the combination of these data sets, estimates
of the uncertainties in the rainfall analysis are provided as a part of the GPCP products.
Click here to learn more about GPCP data
products and how to access them.
The GPCP data have already been found capable of revealing
changes in observed precipitation on seasonal to interannual time scales and in validating
model generated precipitation from re-analysis systems, such as those from NCEP/NCAR and
ECMWF. GPCP also offers the potential for studying changes in the distribution of
precipitation at longer time scales such as predicted by GCM simulations, especially in
the pattern change over previously data-sparse ocean areas. GPCP estimates can validate
both the magnitude and the spatial pattern of modeled rainfall to within the estimated
error of the observations. However, realization of the full potential for the GPCP to
provide precipitation estimates for climate change studies, especially over the oceans,
requires further research and development. Specifically, investigation of inhomogeneities
in the GPCP satellite component data sets, and enhanced calibration and validation
efforts, especially over open oceans, are required.
Click on the figure above to see a larger
version in its own window. In some web browsers you may have to click on the figure again
in the new window to see the larger version.