Understanding moisture and rainfall

The role that atmospheric water vapour plays in weather is complex and not clearly understood. However, U.S. researchers say they are starting to get a handle on it after teasing out the relationship between morning soil moisture and afternoon rainfall under different atmospheric conditions. “The prevailing wisdom… is that if you have wetter soil in the morning, you’ll have a greater occurrence of rainfall in afternoon, but it’s more complicated than that,” says Josh Welty from the University of Arizona, lead author of a paper in Geophysical Research Letters.