Circulation background of the extremely heavy rain causing severe floods in Huaihe River valley in 2003 and its relationship to the apparent heating

摘要

Based on NCEP/NCAR daily reanalysis data and precipitation data, the circulation background of the extremely heavy rain causing severe floods in Huaihe River valley (HHRV) in 2003 and its relationships to the apparent heating were analyzed. The results showed that the El Nino events with middling intensity during 20022003 was the previous background of this extremely heavy rain. The abnormal apparent heating source n k b to_ the HRV during June 21 July 2. The centers of high value bands of and were in agreement with those of rainfall. But the negative abnormal and were situated in South China and most of South China Sea areas. The abnormal heating source over the Bay of Bengal forced an abnormal anticyclonic circulation over its northwest high level leading to the South Asian High enhancing and maintaining over the Tibetan Plateau , the south of Yangtze River valley and South China, so HHRV areas just located the updraft areas which was in the south of the high-level jet , making for heavy rain and severe floods.