资源环境科技发展态势分析平台

On the basis of the daily precipitation records of 442 meteorological stations throughout Northeast Asia (NEA) from 1961 to 2009, this study investigates spatiotemporal changes in summer extreme precipitation (SEP) and the relationship between SEP and East Asia summer monsoon (EASM) in NEA. The results show that the spatial patterns of the trends in SEP indices are similar, with obvious clustering, except for the consecutive dry days (CDD) index. Stations exhibiting increasing trends are mainly located in Eastern China (EC) and the western part of Western Japan (WJ). Stations with decreasing trends are mostly distributed in Northern China (NC) and the southern region of Eastern Japan (EJ). The spatial patterns of the correlations between the EASM index EASMI and the SEP indices are similar, except for the CDD index. Stations that show decreasing trends mostly exhibit positive correlations between SEP indices and the EASMI, and vice versa. The spatial patterns of trends (increasing trends in EC, decreasing trends in NC and Northeast China) in SEP indices between 1961 and 2009 have a correlation with a weakening EASM. This study demonstrates that the mechanism dominating the mean state change of the EASM also applies to SEP. A strong mid-latitude cyclone could result in a regional SEP (R99p occurred in more than 20 stations over a subregion in 1 day) in EC and Japan in weak EASM years, and could result in a regional SEP in NC in strong EASM years.