Summer and winter precipitation in East Asia scale with global warming at different rates

Abstract

Future changes of regional precipitation are of great scientific and societal interests. Large uncertainties still exist in their projections by models. Mechanistic understanding is therefore necessary. Here we demonstrate robust features of the percentage change of precipitation normalized to surface temperature change (%/K) under global warming, referred to as scaling of precipitation with temperature in East Asia. We find that land precipitation in the summer scales at ~3%/K, well below the scaling rate of the Clausius-Clapeyron relationship for atmospheric water vapor content, but the scaling in winter is comparable to the Clausius-Clapeyron scaling at ~7%/K. By using moisture budget analysis of model simulations, we show that this scaling and the seasonal contrast can be clearly attributed to the robust climate changes of steeping moisture gradient, weakening westerly jets, and increasing hydrological amplitude of atmospheric eddies.