摘要
北极河流径流是北冰洋淡水的最大来源,其变化会对北冰洋中的诸多过程有重要影响。本文基于全球高分辨率海洋−海冰耦合模式的模拟结果,研究北冰洋温盐、海冰以及环流对北极河流径流的敏感性。通过对比有气候态北极河流径流输入的控制实验结果和径流完全关闭的敏感性实验结果,研究发现北极径流对北冰洋温度、盐度、海冰以及海洋环流等有显著的影响。关闭北极河流径流后,在河口附近的陆架上温度降低、盐度升高,且导致500 m深度处温度下降以及盐度升高;河口附近的陆架处,海冰密集度与海冰厚度增加。关闭北极河流径流也对北冰洋内的环流有影响:由于缺少来自欧亚大陆的北极径流的输入,穿极漂流与东格陵兰流流速减小且盐度增加;关闭北极径流导致近岸海表面高度降低,沿欧亚陆架的北冰洋边界流减弱,白令海入流增强。通过对比关闭北极径流实验与控制实验的温度和盐度剖面,发现关闭北极径流后大西洋层温度降低,各陆架海盐跃层的梯度减小,盐跃层厚度减小。
River runoff plays a dominant role in the freshwater flux to the Arctic Ocean,and the corresponding changes in river runoff may have important effects on many processes in the Arctic Ocean.In this study,the sensitivity of ocean temperature,salinity,sea ice and circulation to river runoff was investigated by using a global highresolution coupled ocean-sea ice model.By comparing the simulated results from a sensitivity experiment without river runoff with the results from a control simulation with climatology river runoff,we found that the river runoff can significantly modulate the temperature,salinity,sea ice,and ocean currents in the Arctic Ocean.In the sensitivity experiment without river runoff,the sea surface temperature on the shelf near the estuaries decreases,and the salinity increases.At 500 m depth,the temperature decreases,and the salinity increases in the sensitivity experiment.The sea ice concentration and thickness also increase near the estuaries in the sensitivity experiment.The shutdown of the river runoff also has an impact on the circulation,which leads to weaker and fresher East Greenland Current and the Transpolar Drift Stream.The shutdown of runoff forcing can also slow down the Arctic Circumpolar Boundary Current along the Eurasian Shelf and speed up the Bering Strait inflow by lowering the sea surface height in the shelf seas.In the sensitive experiment,a colder Atlantic layer,a smaller salinity gradient and a thinner upper halocline can be identified by comparing with the temperature and salinity profiles from the control experiment.
作者
田霏
王召民
Gavilan Estanislao
刘成彦
Tian Fei;Wang Zhaomin;Gavilan Estanislao;Liu Chengyan(International Polar Environment Research Laboratory,College of Oceanography,Hohai University,Nanjing 210098,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082,China)
出处
《海洋学报》
CAS
CSCD
北大核心
2020年第7期1-15,共15页
基金
国家科技部国家重点研发计划项目(2016YFA0601804)
国家自然科学基金(41876220)
中央高校基本科研业务费专项资金(B200202143)。
关键词
北极河流径流
海洋环流
水团
海冰
Arctic river runoff
oceanic circulation
water masses
sea ice
