波浪辐射应力对海流模式影响的数值分析

A preliminary numerical experiment on effect of wave-induced radiation stress on ocean current model

将波浪辐射应力,特别是地转意义下的波浪辐射应力引入海流数值模式POM(princeton ocean model),在渤海海域进行了初步的数值研究。在目前的数值分析中仅考虑了波浪辐射应力的横向分量(也是最重要的分量)。在POM模式中引入非地转和地转意义下的波浪辐射应力两种方案,并与原模式直接运行(即不考虑波浪辐射应力)的结果进行比较。比较显示,波浪辐射应力,特别是地转意义下的波浪辐射应力对海流模式结果的影响不容忽略。在海浪场存在的条件下,由风应力和地转意义下浪致作用力共同作用产生的海流强度应比理论上Ekman漂流的强度大,尤其是在浪致作用力显著的表层,表层流将明显增强,且不会完全符合Ekman漂流理论的转向规律。

We introduce wave-induced radiation stress （WaRS） , especially geostrophic WaRS, into the ocean current model POM （Princeton Ocean Model） , and carry out a preliminary numerical experiment in the Bohai Sea. We only consider the lateral （and the most important） component of WaRS in the present experiment. It includes the following three runs. Run 1, control run （ with no WaRS）. Run 2, introduce non-geostrophic WaRS derived by Hasselmann （1970）. Run 3, introduce geostrophic WaRS derived by Sun, et al. （2006）. Comparison show-s that the effect of WaRS, especially geostrophic WaRS, on current should not be ignored, which challenges the classic Ekman drift theory. That is, when there exist waves, the magnitude of drift driven by wind and wave together would be larger than the theoretical Ekman drift that is driven only by wind. Besides, the direction of wind- and wave-driven drift does not completely accord ＂with the Ekman drift theory, especially in the upper layer of ocean.