The Climate Hazards Group InfraRed Precipitation with Stations (CHIRPS) v2.0 Dataset: 35 year Quasi-Global Precipitation Estimates for Drought Monitoring

Abstract:

A high quality, long-term, high-resolution precipitation dataset is a key requirement for supporting drought monitoring and long term trend analysis. In this presentation we introduce a new dataset: the Climate Hazards group InfraRed Precipitation with Stations (CHIRPS) v2.0, developed by scientists at the University of California, Santa Barbara and the U.S. Geological Survey Earth Resources Observation and Science Center. This new quasi-global precipitation product is available at daily to seasonal time scales, with a spatial resolution of 0.05°, and a 1981 to near real-time period of record. The three main types of information used in the CHIRPS are: (1) global 0.05° precipitation climatologies, (2) gridded precipitation estimates derived from time-varying cold cloud duration, and (3) in situ precipitation observations.

The Climate Hazards Group (CHG) has developed an extensive database of in situ daily, pentadal, and monthly precipitation totals with over a billion daily observations worldwide. A screening procedure was developed to flag and remove potential false zeros from the daily GTS and GSOD data. These potentially spurious data can artificially suppress CHIRPS rainfall totals.

Using GPCC v7 as the best-available standard, we compare CHIRPS with ARC2, CFS-Reanalysis, CHIRP, CMORPH, CPC-Unified, ECMWF, PERSIANNE, RFE2, TAMSAT, TRMM-RT7, and TRMM-V7. The CHIRPS is shown to have higher correlation, and lower systematic errors (bias) and mean absolute errors with GPCC v7 than the other datasets. Comparison with independent validation data suggests that the CHIRPS performance is similar to research quality products like the GPCC and GPCP, but with higher resolution and lower latency. We conclude by looking at the change in availability of station data within a monitoring time frame, contrasting countries with and without near real time data.