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Members of CCI team co-author article on soil moisture - precipitation feedback in Nature

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Where does it rain on a hot day's afternoon? Satellite data prepared by the VU University Amsterdam and the Vienna University of Technology show that soil moisture plays an important role. Through the synergistic use of active and passive microwave sensors the study showed that soil
moisture influences precipitation in a way that is quite different from
what models have predicted so far: convective precipitation is more
likely to occur over drier soils.

Afternoon storms are more likely to develop when soils are parched, according to a new study published this week in Nature, which examined hydrological processes across six continents.

The results have important implications for the future development of global weather and climate models which may currently be simulating an excessive number of droughts.

The research team included two scientists from the CCI soil moisture group (i.e. Dr. Wouter Dorigo of TU Wien and Dr Richard de Jeu of VU University Amsterdam) and was led by Dr Chris Taylor from the NERC Centre for Ecology & Hydrology in the UK.

The scientists examined imagery from weather satellites which track the development of storm clouds across the globe. When they matched up where new storms appeared alongside images of how wet the ground was as derived from the satellite soil moisture datasets, they were somewhat surprised.

The researchers compared their observations with six global weather and climate models used to simulate climate change. They found that the existing models do the wrong thing, triggering rain over wetter soils.

The implication is that existing climate models are more likely to go into a vicious circle whereby dry soils decrease rainfall, leading to even drier soil conditions. The paper concludes that fixing this problem is a priority for scientists developing the climate models. This paper is a clear example how satellite soil moisture can enhance our knowledge in climate studies.

Reference: Christopher M. Taylor, Richard A. M. de Jeu, Françoise Guichard, Phil P. Harris & Wouter A. Dorigo ‘Afternoon rain more likely over drier soils’ online published on 12 September 2012. www.nature.com DOI 10.1038/nature11377