Between 1951 and 2011 there has been a significant decrease in precipitation during the peak of the summer monsoon season in South Asia, as reported in a paper published online this week in Nature Climate Change. This work improves the understanding of climate change impacts on precipitation extremes, which will facilitate better management of risks, including those related to water resources and agriculture.

Deepti Singh and colleagues applied statistical analysis techniques to precipitation observations from central India over a 60-year period to investigate extreme wet and dry spells. They found that changes in extreme wet and dry spells are a result of altered atmospheric conditions. Wet spells, which increased in intensity during the period studied, are associated with a strengthened low-level anticlockwise atmospheric circulation over the core monsoon region and dry spells, which increased in frequency but decreased in intensity, are associated with a low-level clockwise circulation combined with a higher level anticlockwise circulation over central Asia that brings cold air from the mid-latitudes.