利用多年卫星测高资料研究南海上层环流季节特征

利用10年高精度卫星测高海面高异常网格资料,联合EGM96稳态海面地形模型,构成南海海域合成海面地形的时间序列,并计算了各个时期的南海表层地转流场. 利用卫星跟踪漂流浮标观测结果与相应时期南海地转流场进行对比验证,结果显示本文结果可以很好地反映南海海域一些中小尺度的环流特征. 根据南海各季节多年平均表层环流场结构,对南海环流周年变化规律和季节特征进行了初步的探讨. 研究结果表明,南海表层环流始终处在不断演变过程之中,在时间和空间上都表现出明显的多尺度特征.

Seasonal variations of upper ocean circulation over the South China Sea from satellite altimetry data of many years

We use high-precision gridded sea surface height anomaly data based on more than ten years multi-satellite altimetry observations, associated with EGM96 stationary sea surface topography model, to derive time-varying sea surface topography in the South China Sea (SCS), and calculate the upper level circulation fields at different times. Comparison between the derived result and the drifting buoy tracks from the world data center for drifting buoys suggests that the derived upper level circulation can reveal some meso-scale characteristics of circulations and eddies over SCS. Some analyses about the seasonal characteristics of circulations over SCS are made according to the mean seasonal upper level circulation field. The result shows that due to the various factors, the upper level circulation over SCS changes greatly in different seasons. The route of circulation and the shape, location and strength of eddies are always in a consecutive movement. As a whole, the seasonal variations of circulation over SCS are primary due to monsoon. In summer, the characteristic of circulation is quite opposite to that in winner. There are transitional characteristics which appear in spring and autumn.