Future change in extreme precipitation in East Asian spring and Mei-yu seasons in two high-resolution AGCMs

Precipitation in the spring and Mei-yu seasons, the main planting and growing period in East Asia, is crucial to water resource management. Changes in spring and Mei-yu extreme precipitation under global warming are evaluated based on two sets of high-resolution simulations with various warming patter n of sea surface tem-perature (SST'spa). In the spring season, extreme precipitation exhibits larger enhancements over the norther n flank of the present-day prevailing rainy region and a tendency of increased occurrence and enhanced intensit y in the probability distribution. These changes imply a northward extension of future spring rainband. Although the mean precipitation show s minor change, enhanced precipitation intensity, less total rainfal l occurrence, and prolonged consecutive dry days suggest a more challenging water resource management in the warmer climate. The projected enhancement in precipitation intensity is robust compared with the internal variability related to initial conditions (sigma int) and the uncertai n t y caused by SST'spa (sigma & UDelta;SST). In the Mei-yu season, extreme precipitation strengthens and becomes more frequent over the present-day prevailing rainband region. The thermodynamic component of moisture flux predominantly contributes to the changes in the spring season. In the Mei-yu season, both the thermodynamic and dynamic components of moisture flu x enhance the moistu r e transport and intensi f y the extreme precipitation from souther n China to northeast Asia. Compared with spring season, projecting future Mei-yu precipitation is more challenging because of its higher uncertai n t y associated with 1) the sigma i n t and sigma & UDelta;S S T embedded in the projections and 2) the model characteristics of present-day climatolog y that determines the spatial distribution of precipitation enhancement.

Automated summary

This study evaluates the changes in extreme precipitation in the spring and Mei-yu seasons under global warming. The results show that extreme precipitation in the spring exhibits larger enhancements and a tendency of northward extension, while extreme precipitation in the Mei-yu season strengthens and becomes more frequent. These findings suggest that water resource management will face greater challenges in a warmer climate.