Introduction to the Updated GPCP Monthly Product – V3.1

Abstract:

The Global Precipitation Climatology Project (GPCP) is a long-standing project associated with the World Climate Research Program (WCRP) and the Global Energy and Water Exchanges (GEWEX) project that creates and maintains global precipitation products. The GPCP algorithms have been extensively renovated to improve spatial resolution (0.5°x0.5°, formerly 2.5°x2.5°), and to use updated satellite retrievals from selected Special Sensor Microwave Imager (SSMI) and Special Sensor Microwave Imager/Sounder (SSMIS) (both based on the Goddard Profiing algorithm 2010 Version 2 [GPROF2010v2]), and geosynchronous IR sensors (based on the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record [PERSIANN-CDR] algorithm). At higher latitudes, precipitation estimates are based on Television-Infrared Operational Satellite (TIROS) Operational Vertical Sounder (TOVS) and Advanced Infrared Sounder (AIRS) data. Then, recent climatologies adjust the satellite-only precipitation, with the key step of wedding the Tropical Combined Climatology (TCC) at low latitudes with the Merged CloudSat, TRMM, and GPM (MCTG) climatology at higher latitudes. The finer resolution in V3.1 allows use of the full-resolution TOVS/AIRS estimates and use of the latest Global Precipitation Climatology Centre (GPCC) gauge analyses at 1°x1°. The V3.1 record runs from 1983 (the start of global IR coverage) to the (delayed) present. Because GPROF microwave retrievals are only continuous starting in January 1992, the period 1983 –1991 is computed with climatological scaling.

This talk will compare V3.1 performance to GPCP SG V2.3 and other data sets as a function of time, latitude, and region. In addition to improved resolution, one of the focal points in V3.1 was investigating the peak that earlier versions showed around 60°S, and which is now more realistic-looking.