Gradients in soil moisture over distances of tens of kilometres enhance the probability of rainfall in the Sahel region of Africa, suggests a study published online in Nature Geoscience.
Christopher Taylor and colleagues examine the link between soil moisture and rainfall in the Sahel, using satellite observations of rain storms and soil moisture from 2006 to 2010. They show that rain storms are twice as likely to form over strong gradients in soil moisture compared with uniform soil-moisture conditions. The authors suggest that rainfall events therefore enhance the probability of further rain in the region.
In an accompanying News and Views, Randal Koster writes that the study “provides one of the most careful observation-based analyses of land-atmosphere feedback so far”.