摘要
利用1951～2005年华南地区3月份的降水资料、NOAA海温资料、Nio3.4指数和NCEP再分析资料,分析了华南3月份降水异常与同期环流场、全球海温场的关系,从环流和海温的角度揭示了华南3月份降水异常的可能原因。结果表明,当华南3月份降水偏多(少)时,在对流层中低层,北太平洋海区存在气旋(反气旋)性环流异常,西太平洋及南海海面上存在反气旋(气旋)性环流异常,这样的环流异常有利(不利)于东南暖湿气流与北方东部异常冷空气在华南地区形成水汽辐合,导致降水显著增多(减少)。进一步的分析表明,ENSO和北印度洋及南海附近海温是影响华南3月份降水异常的重要外强迫因子,ENSO对华南3月降水异常的影响是通过影响春季西太平洋副热带高压和低层风场异常实现的,而北印度洋及南海附近海温对华南3月降水异常的影响则是通过垂直环流场异常和低层风场以及西太平洋副热带高压异常来实现的。
The relationships of the March precipitation anomalies over South China with the associated circulation and the global sea surface temperature （SST） field are analyzed by using observations of March rainfall over South China, NOAA SST data, Nifio3.4 index, and NCEP reanalysis data for the period 1951-2005. The possible causes of the March precipitation anomalies over South China were revealed from the point of view of the atmospheric circulation and SST field. The results show that when March rainfall over South China is above （below） normal, a cyclonic circulation （an anticyclonic） anomaly exists in the middle-low-level of the troposphere over the North Pacific Ocean, and an anticyclonic （a cyclonic） circulation anomaly appears over the western Pacific Ocean and the South China Sea. These circulation anomalies are favorable （unfavorable） to the southeast warm-moist air flow and the abnormal cold air in the east ofnorthern China which form a water vapor convergence over South China, leading to a significant increase （decrease） of precipitation. Further analysis showed that the E1 Nifio-Southem Oscillation （ENSO） and North Indian Ocean and South China Sea SST are important external factors that influence the March precipitation anomalies over South China. The influence of ENSO on the March precipitation anomalies over South China is through the western Pacific subtropical high and low-level wind field anomalies, and the influence of the North Indian Ocean and South China Sea SST on the March precipitation anomalies over South China is affected by the vertical circulation and low-level wind field anomalies, as well as the abnormal western Pacific subtropical high.
出处
《大气科学》
CSCD
北大核心
2013年第3期719-730,共12页
Chinese Journal of Atmospheric Sciences
基金
国家重点基础研究发展计划项目2009CB421406
2010CB428403
公益性行业(气象)科研专项GYHY201206041
中国气象局成都高原气象研究所高原气象开放基金课题LPM2012004
国家自然科学基金青年科学基金项目41105073
关键词
华南3月份降水
大气环流异常
ENSO
北印度洋和南海海温异常
March precipitation over South China, Atmospheric circulation anomalies, ENSO, North Indian Ocean andSouth China Sea
