ALERT (October 2014)In the course of ongoing analysis of CHIRPS version 1.8, we found some irregularities in and around Tanzania, especially with respect to trends. We have determined that the cause of the errors were a subset of station data from a particular source. This problem is spatially limited to Central and Northern Tanzania and up to several hundred kilometers into the neighboring countries of Democratic Republic of Congo, Rwanda, Burundi, Uganda and Kenya. This problem is limited to the time period before 2013. All CHIRPS data after January 2013 and outside the areas identified above are unaffected.
This issue will be fixed and a new version of CHIRPS will be released as soon as possible. The next version will benefit from recently acquired station data from around the world as well as several improvements to the CHIRPS processing algorithm.
We thought it important to inform you of this issue now to minimize the effects in your ongoing research and analysis. We apologize for any difficulty this may cause.
Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) is a 30+ year quasi-global rainfall dataset. Spanning 50°S–50°N (and all longitudes), starting in 1981 to near-present, CHIRPS incorporates 0.05° resolution satellite imagery with in-situ station data to create gridded rainfall time series for trend analysis and seasonal drought monitoring. As of May 1st, 2014 version 1.8 of CHIRPS is complete and available to the public. For detailed information on CHIRPS, please refer to our paper on the USGS website.
Since 1999, U.S. Geological Survey (USGS) and CHG scientists, supported by funding from the U.S. Agency for International Development (USAID), the National Aeronautics and Space Administration (NASA), and the National Oceanic and Atmospheric Administration (NOAA), have been developing techniques for producing rainfall maps, especially where surface data is sparse.
Estimating rainfall variations in space and time is an important aspect of drought early warning and environmental monitoring. An evolving dryer-than-normal season must be placed in historical context so that the severity of rainfall deficits may be quickly evaluated. However, estimates derived from satellite data provide areal averages that suffer from biases due to complex terrain which often underestimate the intensity of extreme precipitations events. Conversely, precipitation grids produced from station data suffer in more rural regions where there are less rain gauge stations. CHIRPS was created in collaboration with scientists at the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center in order to deliver reliable, up to date, and more complete datasets for a number of early warning objectives (such as trend analysis and seasonal drought monitoring).
Early research focused on combining models of terrain-induced precipitation enhancement with interpolated station data. More recently, new resources of satellite observations such as gridded satellite-based precipitation estimates from NASA and NOAA have been leveraged to build high resolution (0.05°) gridded precipitation climatologies. When applied to satellite-based percipitation fields, these improved climatologies can remove systematic bias, a key technique in the production of the 1981 to near-present CHIRPS dataset. The creation of CHIRPS has supported drought monitoring efforts by the USAID Famine Early Warning Systems Network (FEWS NET).
Two CHIRPS products are produced operationally: a rapid preliminary version, and a later final version. The preliminary CHIRPS product is available, for the entire domain, two days after the end of a pentad (2nd, 7th, 12th, 17th, 22nd and 27th). The preliminary CHIRPS uses only a single station source, GTS. The final CHIRPS product takes advantage of several other stations sources and is complete sometime after the 15th of the following month. Final monthly, dekad, pentad and daily products are calculated at that time.
Updated regularly at: CHIRPS-latest (tinyurl.com/chg-chirps)
The FAQ for CHIRPS can be found on our wiki.
- U.S. Geological Survey (USGS)
- USGS: Famine Early Warning Systems Network (FEWS NET)
- U.S. Agency for International Development (USAID)
- USAID: Earth Resources Observation and Science (EROS) Center
- National Aeronautics and Space Administration (NASA)
- National Oceanic and Atmospheric Administration (NOAA)
To cite this dataset, please use:
Funk, C.C., Peterson, P.J., Landsfeld, M.F., Pedreros, D.H., Verdin, J.P., Rowland, J.D., Romero, B.E., Husak, G.J., Michaelsen, J.C., and Verdin, A.P., 2014, A quasi-global precipitation time series for drought monitoring: U.S. Geological Survey Data Series 832, 4 p., http://dx.doi.org/110.3133/ds832.
See "A Quasi-Global Precipitation Time Series for Drought Monitoring" for citations used in developing and reporting on CHIRPS.
The Climate Hazards Group InfraRed Precipitation with Stations development process was carried out through U.S. Geological Survey (USGS) cooperative agreement #G09AC000001 "Monitoring and Forecasting Climate, Water and Land Use for Food Production in the Developing World" with funding from: U.S. Agency for International Development Office of Food for Peace, award #AID-FFP-P-10-00002 for "Famine Early Warning Systems Network Support," the National Aeronautics and Space Administration Applied Sciences Program, Decisions award #NN10AN26I for "A Land Data Assimilation System for Famine Early Warning," SERVIR award #NNH12AU22I for "A Long Time-Series Indicator of Agricultural Drought for the Greater Horn of Africa," The National Oceanic and Atmospheric Administration award NA11OAR4310151 for "A Global Standardized Precipitation Index supporting the US Drought Portal and the Famine Early Warning System Network," and the USGS Land Change Science Program.