南海夏季风爆发与热带海洋海温和大气环流异常变化关系的研究

用合成和相关分析方法及SVD技术研究了南海夏季风爆发早、晚年份4～6月季风建立时期季风环流的异常及其与热带太平洋-印度洋海温的关系。结果表明，南海夏季风爆发与热带大气环流和海温变异密切相关。（1）当热带中、东太平洋—印度洋（主要在西南部）及南海海温低（高），西太平洋—澳洲邻近海域海温高（低）时，南海夏季风爆发早（晚）。不同区域海温对季风的影响有明显的季节差异，印度洋主要为晚春至初夏（4～6月），南海为5～6月，而热带太平洋从前冬一直持续到夏季。（2）不同的海温异常产生不同的季风环流型，南海夏季风爆发早、晚年大气环流的异常变化基本相反。南海夏季风的活动主要受印度季风环流变化的影响，与前期冬春季西太副高的强弱及位置变化密切相关。西太副高弱时，南海夏季风爆发早；反之，爆发晚。（3）热带太平洋—印度洋海温异常引起季风环流和Walker环流的异常变化可能是影响南海夏季风爆发早、晚的物理过程。

A Study on the Relationships between the Onset of the South China Sea Summer Monsoon and the Anomalies of Tropical Ocean and Atmospheric Circulations

By using composite, correlate analysis and SVD (Singular Value Decomposition) technique, the relationships among the onset of the South China Sea Summer Monsoon (SCSM), its associated circulation anomalies from April to June and SST anomalies in the tropical Indian-Pacific Ocean were investigated. The results indicate the impacts of SST anomalies in the tropical Indian-Pacific Ocean on the onset of SCSM and its associated monsoon circulation anomalies are significant. The onset of SCSM is early (late) when SST anomalies in the tropical central-eastern Pacific Ocean, Indian Ocean (mainly in the southwestern region) and South China Sea are negative (positive), while SST anomalies in the western Pacific Ocean and Australia's adjacent seas are positive (negative). SST anomalies in different regions of the ocean influence the monsoon in different time: the Indian Ocean is from April to June, South China Sea is May-June, while the influence of the tropical Pacific Ocean can persist from the last winter to this summer. Different SST anomalies can induce different monsoon circulation regimes; circulation anomalies in early or late SCSM are basically reverse. A close relationship exists between SCSM and the activities of the western Pacific subtropical high in previous winter and spring: when the western Pacific subtropical high is weak (strong), the onset of SCSM is early (late). Monsoon circulation and Walker circulation anomalies induced by SST anomalies in the tropical Pacific-Indian Ocean maybe play an important role in influencing SCSM in terms of its onset time.