西太平洋暖池热含量与南海夏季风强度的关系

Relationship between Heat Content over the Western Pacific Warm Pool and Intensity of South China Sea Summer Monsoon

为了进一步明确西太平洋暖池热含量对南海夏季风强度的影响,利用1948～2012年日本气象厅（japan meteorological agency,JMA）逐月的海温资料、Hadley中心的海表面温度（Sea Surface Temperature,SST）资料以及NCEP/NCAR再分析资料,分析比较了南海夏季风强度与热带太平洋上层海洋热含量和SST的关系;探讨了海洋热含量影响南海夏季风强度的机制。结果表明：（1）相比于西太暖池SST,西太暖池上层海洋热含量是南海夏季风强度更好的预测因子;（2）前期冬春季的西太平洋暖池热含量与南海夏季风强度呈现显著的正相关,尤其在3月,二者相关系数最大;当暖池热含量偏高（低）时,西太平洋副热带高压偏弱（强）,赤道印度洋出现异常反气旋（气旋）,印度洋上空的Walker环流分支偏强（弱）,南海越赤道气流增强（减弱）,最终使得南海夏季风强度偏强（弱）。

In this study, we investigate the relationship between the tropical western Pacific upper ocean heat content and the intensity of the South China Sea Summer Monsoon （SCSSM） fron 1948 to 2012, using ocean temperatures from the Japan Meteorology Agency, sea surface temperatures （SSTs） from the Hadley Center, and atmospheric data from the NCEP/NCAR reanalysis I. The main results are as follows. First, compared with the western Pacific warm pool （WPWP） SSTs, the WPWP upper ocean heat content （HC） is more effective as a predictor of SCSSM intensity. Secondly, the SCSSM intensity is highly related to the WPWP HC of the preceding winter and spring, especially in March. When the HC anomalies are positive, an anomalous anticyclone exists over the tropical Indian Ocean and the Walker circulation is strong over the tropical Indian Ocean. As a result, a westerly anomaly prevails over the tropical north Indian Ocean-South China Sea and the cross-equatorial flow over South China Sea is enhanced. In addition, the subtropical high weakens as its position moves northward. All these variations are favorable for the strengthening of the SCSSM.