全球海洋模式对不同强迫场的响应 - 徐永福课题组

虎雅琼,刘海文,李阳春,徐永福
使用全球海洋环流模式LICOM,通过设计三个试验,即以OMIP和WOA09资料为强迫场的试验W,用NCEP/NCAR再分析资料(简称NCEP资料)中的风应力资料代替试验W中的风应力资料的试验M,以及用NCEP资料中的热力强迫代替试验M中的热力强迫资料的试验N,来研究不同的热力和动力强迫场对模式的影响。三个试验的模拟结果均模拟出了水团和流场的分布型和极值区。从三个试验的结果对比可以看出,NCEP资料较弱的风应力使得试验M环流场明显偏弱,减弱了大洋内部的温盐输送,加大了深海温盐模拟结果与观测资料的偏差,但对原模式过强的南极中层水的输送有所改善。NCEP的短波辐射通量和非短波热通量弱于OMIP,且在两极区域NCEP资料的海表温度(SST)比WOA09资料最多低4℃以上。试验N的模拟结果改善了南大洋60°S以南海区试验W 模拟的SST偏高问题,减小了北冰洋部分海域以及副热带大洋东部SST的偏差。此外,试验N高纬度较低的SST增强了北大西洋深水以及南极底层水的输送,因而改善了深海的温盐模拟结果。 三个试验在一些关键海区得到的经向热输送在观测估计及前人模拟结果的范围中,总体上试验M的输送最弱。综合三个试验的模拟结果,可以认为OMIP风应力资料和NCEP SST资料更适合作为LICOM模式的强迫场。

Responses of a Global Ocean Model to Different Forcing Fields
Hu Yaqiong, Liu Haiwen,Li Yangchun,Xu Yongfu
With a global ocean general circulation model, the influences of different thermal and dynamical forcing fields on the model simulation are studied by designing three different numerical experiments, including the run called Exp W with the forcing from OMIP and WOA09, the run called Exp M in which the wind stress in Exp W is replaced with NCEP/NCAR reanalysis data, and the run called Exp N in which the thermal forcing in Exp M is further replaced with NCEP/NCAR data. These simulations were performed with the LASG/IAP climate system ocean model named LICOM. Three numerical experiments all generate the observed features of distributions of water mass and large-scale circulation. A comparison analysis of these three experiments shows that because of weak wind stress in NCEP data, the simulated circulation fields are weaker in Exp M than those in Exp W, including that the transport strength of the Antarctic Circumpolar Current in Exp M is 13% weaker than that in Exp W, and that the strengths of two overturning cells on both sides of the equator and the Deacon Cell are reduced in Exp M, which reduces the transport of temperature and salinity in Exp M, leading to the increase in the differences of temperature and salinity between simulations and observations in the deep water. Because both short-wave radiation fluxes and other non-short-wave thermal fluxes are smaller in NCEP data than those in OMIP data, and the SST in the two polar regions in NCEP data is up to over 4°C smaller than that in WOA09 data, the simulated results from Exp N improve the results with higher SST in the region south of 60°S obtained by Exp W, and reduce the deviation of SST in some areas of the Arctic Ocean and eastern subtropical region obtained in other experiments. In addition, lower SST in the higher region in Exp N enhances the transport of North Atlantic Deep Water and Antarctic Bottom Water, so that the simulated temperature and salinity in the deep water are improved. The meridional heat transport in the critical areas obtained by three experiments generally lies within the uncertainty range obtained with data-based estimate and by other researchers. The meridional heat and volume transports in Exp. M are weakest during these three experiments. Based on the synthesis of three simulation results, it can be considered that the wind stresses of OMIP are more suitable for LICOM than NCEP data.
引用:虎雅琼,刘海文,李阳春,徐永福.2015.全球海洋模式对不同强迫场的响应[J].大气科学
Citation:Liu Haiwen,Li Yangchun,Xu Yongfu.2015.Responses of a Global Ocean Model to Different Forcing Fields[J].Chinese Journal of Atmospheric Sciences (in Chinese)
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Tags: 徐永福, 李阳春, 海洋模式

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