冬季北太平洋海表面热通量异常和海气相互作用的耦合模式模拟

摘要

基于中国科学院大气物理研究所大气科学与地球流体力学数值模拟国家重点实验室(LASG/IAP)开发的耦合气候系统模式FGOALS_s1.0控制试验的积分结果,分析了冬季北太平洋海表面湍流热通量(潜热和感热通量之和)异常及其对海表面温度(SST)异常的影响,并通过分析海温倾向方程,比较了各因子对SST变率的相对贡献.结果表明,模式能基本再现冬季北太平洋海表面热通量的平均态和湍流热通量年际变率的主要特征.在冬季热带外北太平洋上,海洋向大气释放的湍流热通量同SST倾向存在显著的相关.在冬季热带外大部分北太平洋上,湍流热通量异常是决定SST变率的最主要因子,入射短波辐射通量异常只在夏威夷群岛东南侧的一个小区域起主要作用.模式能够较为准确模拟出SST倾向的主要模态和相应的海平面气压场特征.分析表明,模式模拟的北太平洋冬季大尺度的大气环流异常通过影响湍流热通量从而决定SST的变率.文中得出的结果进一步证明"在冬季的热带外北太平洋上,海-气相互作用过程中占主导地位的是大气对海洋的强迫"这个结论是有意义的,LASG新版本耦合模式FGOALS_s亦适用于开展北太平洋海-气相互作用研究.%The anomalous latent and sensible heat flux over the North Pacific in boreal winter and their impact on sea surface temperature (hereafter SST) anomalies are analyzed by using a long-term integration of the ocean-atmosphere coupled model FGOALS_s of LASG/IAP. The relative contributions of heat flux components and oceanic dynamical terms to the SST variance are compared. The results show that the FGOALS_s can reproduce the dominant characteristics of the mean state of surface heat fluxes and the interannual variance of turbulent heat flux. In the extra-tropical North Pacific Ocean, significant correlation exists between anomalous latent and sensible heat flux and SST tendency anomalies in boreal winter. The turbulent heat flux is the most important factor that determine the SST variance, whereas the downward short wave flux is dominant only to the southeast of Hawaii archipelago. The model has a reasonable performance in capturing the leading mode of winter time SST tendency in the extra-tropical North Pacific Ocean and the corresponding pattern of sea level pressure anomalies. Analysis shows that the anomalous large-scale atmospheric circulation affects the turbulent heat flux and thus plays a significant role in changing the SST anomalies. The diagnosis based on model results supports that in the boreal winter extra-tropical North Pacific Ocean, the atmospheric forcing is dominant in the local air-sea interaction processes, and the new edition of the coupled model FGOALS_s is applicable to investigate the air-sea interaction over the North Pacific in wintertime.