基于数值模式的南海北部深层内潮季节变化特征分析

摘要

本文基于MITgcm非静力数值模式,采用实际地形、层结和潮流强迫,开展南海北部内潮数值模拟敏感性试验,分析夏冬两个季节南海北部深层内潮的差异.结果显示在南海北部深层,冬季K1和M2内潮流速振幅比夏季强10.1%和44.7%.垂向模态分析结果进一步表明,尽管南海北部深层冬季第一模态内潮动能密度比夏季低15.5%,但第二和第三模态内潮则是冬季比夏季高约25.1%和33.2%,导致冬季深层流速的垂向剪切大于夏季,表明冬季较强的高模态内潮可能是冬季南海深层强混合的一个原因.%Based on the Massachusetts Institute of Technology General Circulation Model,the numerical simulation of the internal tide in the northern South China Sea(SCS)is carried out by using the actual bathymetry,stratifica-tion and tidal current force.The differences of the internal tide in the northern South China Sea during the two sea-sons are analyzed.The results show that the velocity in the K1and M2is 10.1% and 44.7% stronger than that in the summer.The results of the vertical modal analysis show that although the tidal kinetic energy density in the first modal is 1 5.5 % lower in winter than that in summer,the second and third modal tides are about 25.1 % and 33.2% higher.These high-mode tides may lead to intense vertical shear in the deep basin of SCS in winter,indica-ting that the stronger high-mode tide may be one of the reasons for the intense mixing of the deep SCS in winter.