Assessment shows no trend in global precipitation

There are a limited number of global precipitation data sets available for possible assessments of climate change as carried out by the Intergovernmental Panel on Climate Change or for studies of the global water cycle as called for by the Integrated Global Observing Strategy Partnership Water Cycle Theme (2000). The Global Precipitation Climatology Project (GPCP) data are widely available and comparisons of the data have been performed with other global precipitation data. However, GPCP data had not been independently and thoroughly assessed in terms of how reliable they are in representing temporal and spatial variations of precipitation for climate change and water cycle studies. This is crucial since a variety of satellite precipitation estimates are used in this data set as well as new methodologies for merging satellite and gauge data.