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| 黑潮跨陆架入侵东海年际变化的数值模拟 |
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杨德周1,2,3, 许灵静1,2,4, 尹宝树1,2,3,4, 冯兴如1,2,3, 陈海英1,2,3, 齐继峰1,2,3, 崔煊1,2,4
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1.中国科学院海洋研究所 青岛 266071;2.中国科学院海洋环流与波动重点实验室 青岛 266071;3.青岛海洋科学与技术国家实验室海洋动力过程与气候功能实验室 青岛 266237;4.中国科学院大学 北京 100049
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| 摘要: |
| 为了研究黑潮跨过200m等深线对东海入侵的年际变化特征，本文基于ROMS （Regional Ocean Modeling System）海洋模式，对西北太平洋海域进行了高分辨率的数值模拟，模式水平分辨率高达4km，该分辨率可以很好地分辨黑潮以东区域的中尺度涡旋等过程。模式首先进行了6年的气候态模拟，然后进行了1993到2015年的后报模拟。模式很好地再现了东海陆架已知的环流结构，模拟出的对马海峡和台湾海峡的年平均流量和观测结果也比较一致。基于模式结果，利用旋转经验正交函数（REOF）的方法，对黑潮跨过200m等深线流量的年际变化进行分析。REOF的主要模态表明，黑潮跨过200m等深线对东海陆架的入侵主要发生台湾东北，并且入侵主要集中在黑潮次表层水中。主要模态的时间系数表明，黑潮入侵东海陆架的年平均流量存在一个8年的变化周期。相关性分析表明，黑潮入侵东海陆架的年际变化和太平洋年代际振荡PDO （Pacific Decadal Oscillation）指标具有显著的负相关，其相关系数达-0.63。该相关可以通过如下过程解释：PDO会导致东太平洋风应力涡度异常，由Sverdrup关系可知向赤道的体积输运也会相应地产生异常，根据质量守恒，向赤道体积输运的异常必然通过西边界流-黑潮的异常来平衡，从而导致黑潮入侵东海陆架强烈的年际变化。 |
| 关键词: 黑潮 东海 入侵 ROMS |
| DOI：10.11693/hyhz20170500139 |
| 分类号:P731 |
| 基金项目:中国科学院战略性先导科技专项（A类）项目，XDA11020104号，XDA110203052号；国家自然科学基金项目，41576023号，41376030号，41476019号；国家重点研发计划项目，2017YFC1404000号，2016YFC1401601号。 |
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| NUMERICAL STUDY ON INTER-ANNUAL VARIATION OF CROSS-SHELF INTRUSION OF KUROSHIO INTO EAST CHINA SEA |
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YANG De-Zhou1,2,3, XU Ling-Jing1,2,4, YIN Bao-Shu1,2,3,4, FENG Xing-Ru1,2,3, CHEN Hai-Ying1,2,3, QI Ji-Feng1,2,3, CUI Xuan1,2,4
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1.Institute of Oceanology, Chinese Academy of Science, Qingdao 266071, China;2.Key Laboratory of Ocean Circulation and Waves, Chinese Academy of Science, Qingdao 266071, China;3.Function Laboratory for Ocean Dynamics and Climate, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China;4.University of Chinese Academy of Science, Beijing 100049, China
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| Abstract: |
| In order to examine the inter-annual variation of Kuroshio intrusion across the 200m contour of continental shelf of the East China Sea (ECS), a Regional Ocean Modeling System (ROMS) was used to study water exchange between Kuroshio and ECS. The horizontal resolution was 4 km, in which mesoscale eddies can be resolved. At first, the model was run for six years with climatology forcing, followed by a hindcast run from 1993 to 2015 to analyze the inter-annual variation of volume flux across the 200m contour. A well-known ocean circulation pattern on the ECS shelf is reproduced faithfully in our modeling. In addition, there are good agreements between model results and observed volume flux across Taiwan Strait and Tsushima Strait. Based on numerical model results, annually mean cross-shelf volume flux along 200m contour was investigated. Rotated Empirical Orthogonal Function (REOF) was used to analyze the inter-annual variation of volume flux. The leading modes of REOF show that the Kuroshio intrusion mainly occurs in the subsurface water of the Kuroshio northeast of Taiwan, and clearly shows 8-year-period inter-annual variation in strength. The variation of magnitude correlates to the Pacific Decadal Oscillation (PDO) very well, and its negative correlation coefficient reach as high as 0.63. The good correlation between PDO and inter-annual variation of cross-shelf volume flux could be interpreted as that PDO induced abnormal wind stress curl; it in turn caused abnormal equatorward volume transport according to Sverdrup relation; and finally, the equatorward volume transport must be compensated by intensified western boundary current according to the continuity equation. |
| Key words: Kuroshio East China Sea intrusion ROMS |