Accurate information on precipitation (i.e. rainfall and snowfall) is a prerequisite for almost any scientific undertaking related to hydrological issues. An international team of researchers headed by scientists from the Joint Research Centre has released a novel global precipitation dataset, with high spatial and temporal resolutions (0.25° and 3 hourly, respectively), called Multi-Source Weighted-Ensemble Precipitation (MSWEP).
The MSWEP dataset covers the period 1979–2015, and is unique in that it takes advantage of an unprecedented range of data sources, including rain-gauge measurements, satellite observations, and estimates from atmospheric models, to provide a global picture of historical precipitation, with unparalleled detail.
The following video shows the three-hourly precipitation data in MSWEP, for the seven-month period from June to December 2006. The patchy nature of precipitation in the tropics is clearly evident. This is due to the prevalence of highly local, so-called “convective” storms that develop in warm, moist tropical conditions. By contrast, large, so-called “frontal” storms, which form when cold and warm air masses collide, dominate in northern regions, while large mountain ranges, for example along the Pacific Coast of North America, are characterised by “orographic” storms induced by the uplift of moist air. Never before has there been such an accurate picture of precipitation around the globe.
The MSWEP dataset will enable scientists around the world to better understand the hydrological consequences of increases in atmospheric greenhouse gases and changes in land use. The ultimate aim of this work is to improve our predictions and adaptation strategies for the future, thereby securing the provision of fresh water and reducing the impact of water-related disasters such as floods and droughts.
MSWEP is freely available online, via www.gloh2o.org.
Beck, H.E., A.I.J.M. van Dijk, V. Levizzani, J. Schellekens, D.G. Miralles, B. Martens, A. de Roo: MSWEP: 3-hourly 0.25° global gridded precipitation (1979–2015) by merging gauge, satellite, and reanalysis data, Hydrology and Earth System Sciences Discussions, doi:10.5194/hess-2016–236, 2016.