基于浮标资料的海气动量交换系数研究

Study on Air-Sea Momentum Exchange Coefficient Based on Buoy Data

大尺度模型里大气边界层和海洋表面的耦合通常由海表拖曳系数进行参数化,海表拖曳系数一般看作是风速的函数.低风速下的海表拖曳系数一般看作是风速的线性函数,但有研究显示在极低的风速值下,海表拖曳系数并不是随着风速而单调增加的,而是随着风速的增加先减小再增大.极低风速下海表拖曳系数的估计值对不同计算方法有很强的依赖性,低风速下海表拖曳系数随风速的变化规律存在争议.因此,本文对10m处风速进行4种不同平均方法的选取以探究海表拖曳系数随风速的变化规律,为进一步改进海洋模式提供了依据,提升了海洋再分析的业务化能力.

The coupling of the atmospheric boundary layer and the sea surface in large scale models is often parameterized using the drag coefficient, which is commonly taken as the function of the wind speed. The drag coefficient in low wind speeds is generally regarded as a linear function of the wind speed. However, some studies suggest that the drag coefficient does not monotonically increase with wind speed in extremely low wind speeds. Inversely, it decreases and then increases with wind speed. The evaluation for the drag coefficient in extremely low wind speeds is very sensitive to different calculations and its varying pattern is in dispute. Hence, the drag coefficient derived from four unique processing schemes that involve different methods for averaging the surface stress and the wind speed at 10m are compared to provide reference for further development of ocean models and promote the performance of ocean reanalysis.