The Global Precipitation Climatology Centre (GPCC) is operated by the German Weather Service (DWD) under the auspices of the World Meteorologic Organization (WMO). It has the task of collecting global in-situ precipitation data to produce quantitative global precipitation and water balance analyses.
The "GPCC Full Data Reanalysis" contains sums of precipitation over land and is more than one hundred years long: It starts in 1901 and ends in 2010. For this reanalysis quality controlled data from all globally available land stations (rain gauges) are used. The number of stations that were used to create the gridded data set has spatial and temporal variations, and is therefore included in the data set as a variable. The gridded final data set is optimized for best spatial coverage and use in water balance estimations and was used for trend analysis. This GPCC reanalysis has a higher accuracy in the precipitation data than the near real time products such as the "GPCC Monitoring Product". More detailed information on the methods applied for the preparation and interpolation of the original data can be taken from the cited literature.
The "GPCC Full Data Reanalysis" is available in three spatial resolutions (0.5 °, 1 ° and 2.5 °). ICDC has provided the highest resolution of 0.5 °.
Another interesting product is the GPCC precipitation climatology "GPCC Climatology Version 2011" (link to description and FTP download), which can be used as an addition, for example, the calculation of precipitation anomalies from the reanalysis.