A Sandwich-Like Pattern of Eastern China Summer Precipitation Change Projected by CMIP6 Models

Abstract

A reliable projection of the summer (June–August) mean precipitation over eastern China (EC) in the future is crucial for climate adaptation activities in this densely populated region. In contrast to existing studies, which have primarily focused on the EC mean precipitation change and have demonstrated a wetting trend in the future, this study, based on an analysis of 35 Coupled Model Intercomparison Project Phase 6 models, highlights that the future precipitation rise within the EC area is distributed inhomogeneously with latitudes. The southern and northern EC regions are projected to experience a pronounced increase in precipitation, while the middle EC, where the well-known meiyu-baiu rainbelt is located, is expected to witness a comparatively weaker rise. This sandwich-like pattern is consistent across models and is evident irrespective of future periods and greenhouse-gas-emission scenarios specified. The findings have significant implications for the future management of water resources along China's major rivers, which are all located within the EC. Further analysis of the moisture budget indicates that the dynamical response to global warming is the key driver of this sandwich-like pattern of precipitation change. The relatively weak precipitation increase over the central EC is attributed to the eastward retreat of the western North Pacific subtropical high (WNPSH) in the future, while a more pronounced precipitation increase over the northern EC is related to the enhanced southerly wind along the eastern coast of China.