In this paper,NCEP reanalysis data,intensive observation data collected from field experiment,model simulation data,and topographic trial data are fully analyzed to study a severe heavy rainfall event during 5 6 June ...In this paper,NCEP reanalysis data,intensive observation data collected from field experiment,model simulation data,and topographic trial data are fully analyzed to study a severe heavy rainfall event during 5 6 June 2008 in South China.Unlike most warm region rainfall cases,this one is associated with an obvious vortex system,which draws in water vapor and energy from the southwest monsoon surges ahead of a low trough above the Bengal Bay (BLT,Bengal Low Trough).At the lower troposphere,three currents,especially the southwest current and the east current,converge into the southeast of the vortex.Thus,the distributions of strong vorticity,water vapor,and ascending motion cause frequently occurrence and growth of convection there.The possible reasons for this rainfall event are summarized as a conceptual model.展开更多
Using rainfall data from the Global Precipita- tion Climatology Project （GPCP）, NOAA extended reconstruction sea surface temperature （ERSST）, and NCEP/NCAR reanalysis, this study investigates the interannual varia...Using rainfall data from the Global Precipita- tion Climatology Project （GPCP）, NOAA extended reconstruction sea surface temperature （ERSST）, and NCEP/NCAR reanalysis, this study investigates the interannual variation of summer rainfall southwest of the Indian Peninsula and the northeastern Bay of Bengal associated with ENSO. The composite study indicates a decreased summer rainfall southwest of the Indian Penin- sula and an increase in the northeastern Bay of Bengal during the developing phase, but vice versa during the decay phase of E1 Nifio. Further regression analysis dem- onstrates that abnormal rainfall in the above two regions is controlled by different mechanisms. Southwest of the Indian Peninsula, the precipitation anomaly is related to local convection and water vapor flux in the decay phase of E1 Nifio. The anomalous cyclone circulation at the lower troposphere helps strengthen rainfall. In the northeastern Bay of Bengal, the anomalous rainfall depends on the strength of the Indian southwest summer monsoon （ISSM）. A strong/weak ISSM in the developing/decay phase of E1 Nifio can bring more/less water vapor to strengthen/weaken the local summer precipitation.展开更多
基金supported by the Tropical Western-Pacific Observation and Predictability (Grant No.GYHY200706020)the National Basic Research Program of China(Grant No. 2009CB 421401)the National Natural Science Foundation of China (Grant Nos. 41175038,40930951,and 40375008)
文摘In this paper,NCEP reanalysis data,intensive observation data collected from field experiment,model simulation data,and topographic trial data are fully analyzed to study a severe heavy rainfall event during 5 6 June 2008 in South China.Unlike most warm region rainfall cases,this one is associated with an obvious vortex system,which draws in water vapor and energy from the southwest monsoon surges ahead of a low trough above the Bengal Bay (BLT,Bengal Low Trough).At the lower troposphere,three currents,especially the southwest current and the east current,converge into the southeast of the vortex.Thus,the distributions of strong vorticity,water vapor,and ascending motion cause frequently occurrence and growth of convection there.The possible reasons for this rainfall event are summarized as a conceptual model.
基金supported by the National Basic Research Program of China(973 Program,2010CB950302&2012 CB955603)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.XDA05090404)the National Natural Science Foundation of China(41149908)
文摘Using rainfall data from the Global Precipita- tion Climatology Project （GPCP）, NOAA extended reconstruction sea surface temperature （ERSST）, and NCEP/NCAR reanalysis, this study investigates the interannual variation of summer rainfall southwest of the Indian Peninsula and the northeastern Bay of Bengal associated with ENSO. The composite study indicates a decreased summer rainfall southwest of the Indian Penin- sula and an increase in the northeastern Bay of Bengal during the developing phase, but vice versa during the decay phase of E1 Nifio. Further regression analysis dem- onstrates that abnormal rainfall in the above two regions is controlled by different mechanisms. Southwest of the Indian Peninsula, the precipitation anomaly is related to local convection and water vapor flux in the decay phase of E1 Nifio. The anomalous cyclone circulation at the lower troposphere helps strengthen rainfall. In the northeastern Bay of Bengal, the anomalous rainfall depends on the strength of the Indian southwest summer monsoon （ISSM）. A strong/weak ISSM in the developing/decay phase of E1 Nifio can bring more/less water vapor to strengthen/weaken the local summer precipitation.
