| XIA Ruibin,LIU Qinyu,XU Lixiao,LU Yiqun. 2015. North Pacific Eastern Subtropical Mode Water simulation and future projection. Acta Oceanologica Sinica, 34(3):25－30 |
| North Pacific Eastern Subtropical Mode Water simulation and future projection |
| 北太平洋副热带东部模态水现在和未来的模拟分析 |
| Received:June 11, 2014 Revised:December 18, 2014 |
| DOI：10.1007/s13131-015-0630-y |
| Key words:eastern subtropical mode water global warming mixed layer depth subduction rate heat advection |
| 中文关键词: 副热带东部模态水 全球变暖 混合层深度 潜沉率 热平流 |
| 基金项目: |
| Author Name | Affiliation | E-mail | | XIA Ruibin | Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology, Key Laboratory of Ocean-Atmosphere Interaction and Climate in Universities of Shandong, Ocean University of China, Qingdao 266100, China | | | LIU Qinyu | Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology, Key Laboratory of Ocean-Atmosphere Interaction and Climate in Universities of Shandong, Ocean University of China, Qingdao 266100, China | liuqy@ouc.edu.cn | | XU Lixiao | Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology, Key Laboratory of Ocean-Atmosphere Interaction and Climate in Universities of Shandong, Ocean University of China, Qingdao 266100, China | | | LU Yiqun | Physical Oceanography Laboratory/Qingdao Collaborative Innovation Center of Marine Science and Technology, Key Laboratory of Ocean-Atmosphere Interaction and Climate in Universities of Shandong, Ocean University of China, Qingdao 266100, China | |
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| Abstract: |
| The present climate simulation and future projection of the Eastern Subtropical Mode Water (ESTMW) in the North Pacific are investigated based on the Geophysical Fluid Dynamics Laboratory Earth System Model (GFDL-ESM2M). Spatial patterns of the mixed layer depth (MLD) in the eastern subtropical North Pacific and the ESTMW are well simulated using this model. Compared with historical simulation, the ESTMW is produced at lighter isopycnal surfaces and its total volume is decreased in the RCP8.5 runs, because the subduction rate of the ESTMW decreases by 0.82×10-6 m/s during February-March. In addition, it is found that the lateral induction decreasing is approximately four times more than the Ekman pumping, and thus it plays a dominant role in the decreased subduction rate associated with global warming. Moreover, the MLD during February-March is banded shoaling in response to global warming, extending northeastward from the east of the Hawaii Islands (20°N, 155°W) to the west coast of North America (30°N, 125°W), with a maximum shoaling of 50 m, and then leads to the lateral induction reduction. Meanwhile, the increased northeastward surface warm current to the east of Hawaii helps strengthen of the local upper ocean stratification and induces the banded shoaling MLD under warmer climate. This new finding indicates that the ocean surface currents play an important role in the response of the MLD and the ESTMW to global warming. |
| 中文摘要: |
| 本文利用GFDL-ESM2M模式模拟结果对北太平洋副热带东部模态水（ESTMW）在现在和未来全球变暖气候背景下的气候态分布进行了分析。结果表明该模式能够较好的地模拟ESTMW和混合层深度（MLD）的空间分布结构。与历史情景模拟结果相比，在RCP8.5实验中，ESTMW形成于更轻的位密面上，并且体积减小。这种变化是因为二、三月份模态水的潜沉率减少了0.82×10-6 m/s。同时，我们发现侧向潜沉率的变化是艾克曼抽吸速率变化的4倍以上，所以全球变暖后潜沉率的减少主要是由侧向潜沉率的减少决定的。全球变暖后二、三月份的MLD呈带状变浅，从夏威夷岛以东 (20°N, 155°W) 向东北延伸到北美西海岸 (30°N, 125°W)，其中最大变浅值可达50 m，这种变化是导致侧向潜沉率变小的主要原因。MLD的带状变浅与夏威夷岛以东增强的向东北的表层暖平流一致，因为这种平流变化有助于增强局地海洋的上层层结，从而使MLD变浅。该发现表明海洋上层平流变化在MLD和ESTMW对全球变暖的响应中起到重要作用。 |
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