Summer Precipitation Change over Eastern China in Future 30 Years Under SRES A2 Scenario

By using the nested regional climate model (NCC/IAP T63-RegCM_NCC), climate change over China during the past 30 years (1961 —1990) is simulated as the control run of the climatic background.Based on it, under the IPCC SRES A2 emission scenario, projection is made over East Asia with the aim of examining climate change scenarios for the future 30 years (2001—2030).The changes of summer precipitation are analyzed, with the key focus on the eastern China monsoon regions.The results show that, due to the effect of greenhouse gas increase, the summer mean precipitation presents increasing trend over northern regions but decreasing over southern regions.The summer rain belts expressed by rainfall departure are expected to shift to the North of Yangtze River.Furthermore, the increase of the total precipitation over northern regions is mainly caused by the increase of convective precipitation, with non-convective precipitation unchanged.With regard to the climate field of 1961—1990, annual mean precipitation in North China (35°—40°N, 110°—120°E) shows less increase by 2%—3% in the next 30 years, but summer mean precipitation is expected to increase remarkably with the maximum precipitation variability of about 19%.Based on the projection, drought over North China in summer is expected to be relieved to some extent in the next 30 years.Summer mean air moisture (especially in lower-layers) is also expected to change obviously in the future, with the atmosphere becoming wetter in mid-high latitude but drier in low latitude regions. East Asian summer monsoon will be much intensive during 2001 —2030.The southwesterly airflow is expected to be enhanced in eastern monsoon regions, which would lead to more warm and wet moisture transporting to the regions of northern China and then increasing the precipitation over that region.Considering the reliability of the projection mainly lies on the capability of the global and regional models as well as the reliability of greenhouse gases concentration, further experiments and integrated comparisons need to be done in the future.Based on the constant improvement of the GCM and RCM, the optimized schemes and the appropriate emission scenarios relative to the different research aim are needed to be chosen.Furthermore, other kinds of the greenhouse gases and aerosols also should be included in the model to decrease the uncertainties in the future climate projection.