ESRL/PSD Seminar Series

Abstract

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As the planet warms, climate models predict that rain will become heavier and less frequent, and circulation will weaken. In this talk we will explore one way to quantify the distribution of rain, how it changes, and the role that changing circulation plays.

To quantify the distribution of rain, we focus on daily precipitation accumulation from CMIP5 models. These models have a wide range of responses to global warming, especially at the extreme end of the distribution. In order to interpret this range of responses, we introduce shift and increase modes of change of the distribution. These capture the response of the entire distribution well in some models, while other models also have an extreme mode, isolates at the heaviest rain rates.

We use two heuristic models to show how changes in moisture and vertical velocity distributions can affect the distribution of rain. An increase in skewness of the vertical velocity distribution is a crucial element to explain the change in the distribution of rain, particularly the decrease in the total number of rain events.

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