一维海洋混合层模式应用于二维数值模拟的试验研究

基于一个一维湍能海洋混合层模式,发展了一个易于与大气或海洋模式耦合的,可应用于水平二维空间的模块化海洋混合层模式。并加入垂直上翻参数化方案,引入日平均海面温度及气候态松弛项,进行二维海洋模拟理想气旋实验和飓风实例模拟实验。理想气旋强迫实验表明,垂直上翻过程的参数化方案可有效地弥补原有一维海洋混合层模式无法形成气旋中心动力上翻的不足,消除了虚假暖水核心。卡特里娜飓风个例实验的结果表明,加入垂直上翻后,飓风中心附近的海表面温度误差明显减小。海洋混合层模式对海洋表面温度日变化模拟能力在二维应用中依然表现良好。经过上述改进,发展的海洋混合层模式可以较为真实地模拟平常海表温度高频日变化的同时,还对剧烈天气过程也有一定的模拟能力,具有广泛的应用前景。

A multilevel ocean mixed-layer model for 2-dimension applications

A multilevel mixed-layer ocean model (MLOM) is improved for a general 2-D application of coupling with atmospheric or oceanic circulation models.This includes the parameterization of the Ekman upwelling pumping (UPW), the nudging of past daily sea surface temperature (SST) variation, and the relaxation to monthly mean climatological state (temperature, salinity, current) profiles.The performance of the MLOM is examined by an ideal experiment of a static storm and a real simulation of Hurricane Katrina 2005.For the static storm, the missing horizontal transport in the 1-D MLOM is effectively compensated by the UPW, and the unrealistic warm core underneath the storm center was also eliminated.In the Katrina case, the MLOM with the three improvements not only realistically simulates SST daily evolution and mean diurnal cycle, but also significantly reduces the SST warm bias along the hurricane track near the center over the Gulf of Mexico.These results suggest that the new MLOM can facilitate a more credible application in hurricane forecasts.