A Study of the Synoptic-Climatology of the Meiyu System in East Asia
DING Yi-Hui1,LIU Jun-Jie2,SUN Ying1,LIU Yan-Ju1,HE Jin-Hai2,and SONG Ya-Fang11 Laboratory for Climate Studies,China Meteorological Administration,National Climate Center,Beijing 1000812 Nanjing University of Information Science and Technology,Nanjing 210044
By using NCEP reanalysis datasets and daily surface observations at 740 stations in China,the climatological aspect of the East Asian rainy season(Meiyu) has been studied.The results have shown that this unique East Asian rainy season in early summer in the Yangtze River basin has an average duration of 21 days,starting from June 17 and ending on July 8.Its concentrated and intensive rainfall of 200-300 mm accounts for about 45% of total summer rainfall amount.The East Asian rainy season occurs when the East Asian summer monsoon abruptly jumps northward from South China to the Yangtze River basin in mid-June and at the same time the Indian summer monsoon sets in over the Indian Peninsula.The moisture supply coming from the South China Sea and the Bay of Bengal is greatly enhanced,thus providing a very favorable condition for Meiyu rainfall.The structure of the climatological Meiyu front is characterized by strong convective precipitation embeded in nearly zonal wide cloud zone,highly moist air column ahead of the Meiyu front of high θse,relatively lower temperature field with very weak or nearly dissipating horizontal temperature gradient across the Meiyu front at low level,strong low-level jet to the south of the Meiyu zone and wind shear line accompanying the Meiyu front,and strong upward motion in the Meiyu zone,with a monsoon type or indirect vertical circulation dominating the region equatorward from the Meiyu zone.In many ways,the Meiyu front in East China is quite different from the Baiu front in Japan and the Changma front in Korea,which are basically of mid-latitude baroclinic frontal zone.The East Asian summer monsoon has a more significant effect on the Meiyu in China than the Baiu and Changma.A comprehensive intercomparison of regional differences of the Meiyu system has been made.
【Fund】： 国家重点基础研究发展规划项目2006CB403604;; 科技部十五攻关项目中国气候变化检测和预测(2001-2005);; 科技部攀登A项目SCSMEX项目(1997-2002)
【CateGory Index】： P466
【CateGory Index】： P466