2004年秋季冷空气活动对南海海表温度的影响

Impact of cold surges on sea surface temperature in South China Sea in autumn of 2004

利用航次观测和网上的有关资料对南海2次强度不同的冷空气活动及其对南海SST的影响进行了分析。结果显示,9月22日弱冷空气过程南下速度慢,在陆地上变性较明显,未造成南海SST的明显变化;而10月2日前后的强冷空气过程南下速度快,陆地上变性比较弱,造成南海SST明显下降。通过对南海海表热收支分析,发现南海北部SST下降主要是冷空气造成净热通量急剧增加,海洋失去热量,而南部SST下降可能是南部海面气旋式风应力引起的下层冷水上涌。初步解释了2004年秋季冷空气活动对南海SST的影响。

Using in situ R/V data, weather charts, TMI AMSRE satellite remote sensing data and NCEP/ NCAR reanalysis data, two cold surges during the period from September 16 to October 4, 2004, and their influences on SST in the South China Sea were studied. The results showed that the weak cold surge propagated slowly southward, and its transformation over land was prominent, the response of SST in the South China Sea was not evident; while the subsequent strong cold surge moved rapidly, and its transformation over land was weak, so the SST＇s response was remarkable. According to sea surface heat budget analysis, the decrease of SST in the northern South China Sea is mainly due to net heat flux, and that in the southern South China Sea is mainly caused by the sub-surface cold water entrainment induced by cyclonic wind stress curls.