大气科学2012，Vol.36Issue(1)：204-214,11.
华南秋旱的大气环流异常特征
Characteristics of General Circulation Anomalies Related to the Drought Events in Fall in South China
摘要
Abstract
The Characteristics of regional droughts in fall in South China and related general circulation anomalous patterns are statistically analyzed with the observed precipitation data and the NCEP/NCAR reanalysis data from 1968 to 2009. The seasonal droughts in fall in South China occurred mainly in the region-wide event. There exist two dominant patterns of sea surface temperature anomalies (SSTA) related to the fall droughts in South China. The first SSTA pattern shows positive anomalies in the tropical western Pacific and the Maritime Continent in a horseshoe-shape and negative anomalies in the western tropical Indian Ocean, the area from the South China Sea northeastward to the subtropical northwestern Pacific and the central and eastern tropical Pacific with a cooling center in the east. The second SSTA pattern exhibits a feature of negative anomalies in the tropical and subtropical western Pacific, the South China Sea, and the tropical Indian Ocean, and positive anomalies in the tropical central and east-ern Pacific and the subtropical northeastern and southeastern Pacific. Corresponding to the first SSTA pattern? The fall droughts in South China result from the enhanced ascending motion over the Maritime Continent and its surrounding area, which is forced by the warmer underlying sea surface temperature. However, corresponding to the second SSTA pattern, the droughts in South China mainly result from the prominent anomalous ascending motion over Northeast Asia which might be forced by the adjustment of the large-scale synoptic activities in the mid-latitudes. The anomalous ascending motion over the subtropical northwestern Pacific to the east of Taiwan and the Philippines exerts also influence on the fall drought events in South China. Two categories of fall droughts in South China are induced by the anomalous descending motions over South China, which are forced by the anomalous general circulation. Furthermore, the two categories of droughts in South China are related to the decrease of tropical cyclones in fall over the central and northern South China Sea and the increase of tropical cyclones over the subtropical northwestern Pacific east of Taiwan and the Philippines, which reduces the frequency of tropical cyclone landfall on South China and thus results in the fall drought events.关键词
干旱/大气环流/海表温度/热带气旋/华南Key words
drought/general circulation/sea surface temperature/tropical cyclone/South China分类
天文与地球科学引用本文复制引用
简茂球,乔云亭..华南秋旱的大气环流异常特征[J].大气科学,2012,36(1):204-214,11.基金项目
国家自然科学基金资助项目40730951,国家重点基础研究发展计划项目2009CB421404 （）
