| 摘要: |
| 建立一个二层非线性原始方程海洋模式，用以研究海洋对静止和以不同移速移动的热带气旋（TC）的响应。数值试验结果表明，海洋对静止TC的响应，具有不对称性；在TC中心处，抽吸使混合层（ML）变浅，在TC最大风速半径处，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。 |
| 关键词: 海洋模式 热带气旋 数值计算 |
| DOI： |
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| 基金项目:国家“八五”科技攻关906项目07专题部分资助 |
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| STUDY ON THE RESPONSE OF OCEAN TO TROPICAL CYCLONES I. THE RESPONSE OF OCEAN TO STATIONARY AND DIFFERENT SPEED TROPICAL CYCLONES |
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Zhu Jianrong1, Qin Zenghao2
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1.Institute of Estuarine and Coastal Research, East China Normal University, Shanghai 200062;2.Shanghai Typhoon Institute, Shanghai 200030
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| Abstract: |
| A two-layer nonlinear primitive equation model based on the mass continuity, momentum and heat balance is developed to study the response of ocean to a tropical cyclone (TC). A turbulent kinetic energy budget is used to parameterize the wind stress-induced vertical mixing (entrainment). The domain of numerical calculation is the northwest Pacific and the real shape of the coast is considered. Numerical experiments indicate that oceanic response to stationary TC is asymmetric due to the Coriolis parameter’s change with latitude. The mixed layer (ML) becomes shallower due to pumping induced by the strong divergency of current at the TC center. Within the maximum wind radius of the TC, the ML becomes obviously deeper and the sea surface temperature (SST) drops mainly due to gale entrainment.
The rightward trend of the current response is obviously related to the moving TC track. This is because the wind speed on the right side of the track is larger than that on the left side; more important, on the right side, the wind stress vector turns clockwise with time which is roughly resonant with the current which also turns clockwise because of the Coriolis force. Whereas this process is just inverse on the left side of the TC track. Because the time scale of current response to wind stress is shorter, the TC moving speed does not greatly affect current velocity. The time scale of response of the ML and SST is longer, thus the moving speed determines how long the ocean is forced by the gale stress. As a result, their value and area changes are very sensitive to the TC moving speed. The response of the ML and SST to the moving TC has a rightward trend, and is more obvious when the TC moves faster. |
| Key words: Ocean model, Tropical cyclone, Numerical calculation |
