南海及周边地区云量分布及低云量与南海海温的关系

利用国际卫星云气候计划提供的月平均云气候资料集,分析了南海及周边地区云量的分布特征,并进一步研究了低云量与南海海温的关系。结果表明:(1)南海及周边地区总云量分布存在显著的季节性差异特征。(2)低云主要分布在南海海区,中云为华南地区,而高云则主要位于靠近赤道区域。(3)低云受海表温度影响较大,而中高云则主要与强对流相对应。低云主要分布于南海海表冷水中心南侧的暖水区内的温度梯度区,其高值区分布与海表温度梯度分布基本一致,海表温度梯度的大小与高值中心的低云量成正比。(4)低云量高值中心位置与水平海温梯度区两侧基本一致,高温暖水受西边界强迫上升在海表层辐合,有利于低云的生成。

Distribution of the cloud amount and correlation between low cloud and the temperature over the South China Sea

Using the International Satellite Cloud Climatology Project (ISCCP) monthly climate dataset, the distributions of the cloud amount over the South China Sea (SCS) and its neighborhood is studied, and the correlation between the low cloud and the temperature over SCS is further researched. The results show that:(1) There is remarkable seasonal feature of the distribution of total cloud amount. (2) The low cloud amount primarily distributes in SCS, the middle cloud amount primarily distributes in the region of south China, and the high cloud amount primarily distributes in the equatorial region. (3) The low cloud is influenced by SST over the SCS. The middle and high cloud are correlated to the strong convection. The low cloud distributes in the area of SST gradient of the warm sea region which lies in the south of the cold water center. The distribution of high value area of low cloud amount is consistent with the SST gradient. (4) The location of high-value center of low cloud amount is basically consistent with both sides of horizontal surface tempeature gradient. Forced by the western boundary, the warm water rises to the sea surface layer and leads to convergence, it is conducive to the formation of low cloud.