Global and Terrestrial Precipitation Climatologies: An Overview and Some Intercomparisons

Over the years, a number of climatological precipitation data sets have been compiled from conventional rain-gauge measurements, mainly from land based stations. Besides, remotely sensed precipitation data caid accumulated short-range forecasts from numerical weather prediction models are also used for studies of the globed climate and its variability. The different data sets comprise station-related time-series, climatological normals or long-term means, isohyetal maps as well as global or continental gridded data, A first purpose of this paper is to give a brief but probably incomplete overview of existing sources of precipitation information Second, some of the mostly used gridded climatologies including the new, still preliminary results of the GPCC are compared, A distinction is made between continental and oceanic areas. It is shown that the precipitation estimates are in reasonable agreement both in temporal and spatial variation, although some large regiorud differences were found having to be interpreted.