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建立一个二层非线性原始方程海洋模式,研究东中国海对热带气旋(TC)的响应。采用湍流动能收支参数化风应力产生的垂直混合(夹卷)。数值试验结果表明,在TC中心处,由海流的强烈辐散引起的抽吸使混合层(ML)变浅。在TC最大风速半径附近,主要由大风夹卷明显使ML加深和海表温(SST)下降。海洋对移动TC的响应,具有右偏性,且随移速加快而加剧。ML深度和SST的变化对TC移速十分敏感,而海流则不同。在考虑不同的海洋热力结构情形下,ML深度和层结强度对SST和ML深度变化起着十分重要的作用。初始ML深度对海流量值影响较大,层结强度则较小,东中国海ML深度的分布,尤其是陆架构特殊的海洋热力结构,极易造成SST下降。海洋对7002号台风响应的模拟结果与观测资料较一致。关键词海洋模式,热带气旋,混合层,夹卷
The establishment of a two-layer nonlinear model of the original ocean equations to study the East China Sea response to the tropical cyclone (TC). Turbulent kinetic energy balance is used to parameterize the vertical mixing (entrainment) of wind stress. The numerical results show that at TC center, the suction caused by the strong divergence of ocean current makes the mixed layer (ML) shallow. Near the TC maximum wind speed radius, the deepening of ML and the decrease of sea surface temperature (SST) were mainly caused by the strong winds. The response of oceans to moving TCs is right-biased and aggravates as the speed of movement increases. ML depth and SST changes are very sensitive to TC velocity, while the current is different. Considering different ocean thermal structures, ML depth and stratification intensity play an important role in the SST and ML depth variations. The initial ML depth has a great influence on the current value and the layer strength is small. The distribution of the ML depth in the East China Sea, especially the special thermal structure of the continental shelf, can easily lead to the decrease of SST. The ocean response to typhoon 7002 is more consistent with the observed data. Key words ocean pattern, tropical cyclone, mixed layer, clip roll