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于子棚, 刘海龙, 林鹏飞. 潮汐混合对大西洋经圈翻转环流(AMOC)模拟影响的数值模拟研究[J]. 大气科学, 2017, 41(5): 1087-1100. DOI: 10.3878/j.issn.1006-9895.1702.16263
引用本文: 于子棚, 刘海龙, 林鹏飞. 潮汐混合对大西洋经圈翻转环流(AMOC)模拟影响的数值模拟研究[J]. 大气科学, 2017, 41(5): 1087-1100. DOI: 10.3878/j.issn.1006-9895.1702.16263
Zipeng YU, Hailong LIU, Pengfei LIN. A Numerical Study of the Influence of Tidal Mixing on Atlantic Meridional Overturning Circulation (AMOC) Simulation[J]. Chinese Journal of Atmospheric Sciences, 2017, 41(5): 1087-1100. DOI: 10.3878/j.issn.1006-9895.1702.16263
Citation: Zipeng YU, Hailong LIU, Pengfei LIN. A Numerical Study of the Influence of Tidal Mixing on Atlantic Meridional Overturning Circulation (AMOC) Simulation[J]. Chinese Journal of Atmospheric Sciences, 2017, 41(5): 1087-1100. DOI: 10.3878/j.issn.1006-9895.1702.16263

潮汐混合对大西洋经圈翻转环流(AMOC)模拟影响的数值模拟研究

A Numerical Study of the Influence of Tidal Mixing on Atlantic Meridional Overturning Circulation (AMOC) Simulation

  • 摘要: 海洋中的潮汐混合对大西洋经圈翻转环流AMOC(Atlantic Meridional Overturning Circulation)模拟的影响是海洋环流模式研究的热点问题之一。本文采用IAP/LASG发展的气候系统海洋模式LICOM(LASG/IAP Climate system Ocean Model)及与海冰耦合模式进行了有无潮汐混合方案的试验,重点探讨了潮汐混合对AMOC强度模拟的影响。结果显示,引入潮汐混合后模拟的AMOC强度极大值比对照试验增加约1倍,更接近RAPID(Rapid Climate Change Programme)观测。而且,潮汐混合试验中模拟的AMOC上层环流深度(3200 m)比对照试验加深1000 m左右,同样更接近RAPID观测。海洋底部的垂直混合增强,使海洋层结变得更加不稳定,加强了北大西洋高纬地区,特别是拉布拉多海等地区的深对流,这是AMOC加强的直接原因。同时,潮汐混合试验中上层海洋环流也加强,增加了中低纬副热带高盐海水向高纬输送,使表层增密,海洋层结更加不稳定,也可以进一步增强AMOC。

     

    Abstract: The impact of the tidal mixing on the simulation of the Atlantic Meridional Overturning Circulation (AMOC) is an important issue in the ocean general circulation model. The response of AMOC to the tidal mixing is investigated in this study by comparing two experiments with and without tidal mixing using the LASG/IAP Climate System Ocean Model version 2 (LICOM2) that is coupled with the Community Ice Code version 4 (CICE4). The study is focused on impacts of tidal mixing on the change of AMOC intensity in the model. The simulation results show that the maximum strength of AMOC in the experiment with tidal mixing is closer to the value provided by RAPID (Rapid Climate Change Programme), which is almost double that in the control experiment without considering the tidal mixing. Meanwhile, the NADW cell reaches a depth of 3200 m, about 1000 m deeper than that in the control experiment, and is closer to that of the RAPID. The enhanced vertical diffusivity near the seafloor topography in the experiment with tidal mixing leads to a more unstable ocean stratification, which will enhance deep convection in the high latitudes of North Atlantic, especially in the Labrador Sea. This will strengthen AMOC intensity directly. Meanwhile, the upper ocean circulation is stronger in the experiment of tidal mixing, bringing more heat and salinity from the subtropics to the high latitudes and leading to denser surface water. The denser water subsequently destroys the stable stratification and intensifies the deep convection, resulting in stronger AMOC indirectly.

     

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