Improvement of ocean mixed layer model toward the accurate prediction of future global warming

利用大涡模拟模式，对不同风应力、加热和冷却强迫情景下的海洋混合层过程进行了理想数值实验；所得结果用于评价应用最广泛的Mellor-Yamada （MY）混合层模型。根据最近对大气混合层的研究，我们修改了湍流长度尺度和稳定性函数的公式，以改善在每种强迫情景下再现上层海洋响应的性能。接下来，我们将这种改进的混合层模式纳入海洋环流模式，以评估其在海洋实际情况下的性能。数值结果与西北太平洋地区的观测结果对比表明，在夏季台风通过后的强风强迫和冬季海面下的冷却条件下，该模式的表现明显优于原MY模式。

Using the large eddy simulation model, we have carried out idealized numerical experiments for the oceanic mixed layer processes under several forcing scenarios consisting of wind stress, heating, and cooling; the obtained results were used to assess the most widely used Mellor-Yamada (MY) mixed layer model. We have modified its formulation on the turbulent length scale and the stability functions following the recent study of the atmospheric mixed layer to improve the performance in reproducing the upper ocean response under each forcing scenario.We have next incorporated thus modified mixed layer model into an ocean general circulation model to assess its performance in the realistic situations in the ocean. Comparing the numerical results with the observed ones in the northwestern Pacific, it has been shown that this model performs much better than the original MY model under strong wind forcing after passage of typhoons in summer and under sea surface cooling in winter.