Wind-forced depth-dependent currents over the eastern Beaufort Sea continental slope: Implications for Pacific water transport
Wind-forced depth-dependent currents over the eastern Beaufort Sea continental slope: Implications for Pacific water transport
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波弗特海东部大陆坡上受风力影响的深度洋流：对太平洋水运的影响
DOI：
10.1525/elementa.321
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发表时间：
2017
期刊：
影响因子：
3.2
通讯作者：
D. Barber
中科院分区：
文献类型：
--
作者：
I. Dmitrenko;S. Kirillov;P. Myers;A. Forest;B. Tremblay;J. Lukovich;Y. Gratton;S. Rysgaard;D. Barber
太平洋水对北冰洋淡水预算贡献很大。最近北极淡水通量的增加，也受到来自太平洋的北极水的影响，影响了大西洋翻转环流，对全球气候产生影响。对太平洋水外流的年际变化仍然知之甚少，部分原因是太平洋水流在北冰洋有不同的分支。博福特海大陆坡上的陆架流沿着博福特海大陆坡向东向加拿大群岛输送了约50%的太平洋水。2003年10月部署在东博福特海大陆坡的海洋学系泊记录了2005年9月之前28-108米深度的流速。数据分析表明，这些高能电流有两种不同的模式的深度依赖行为。与经过博福特海大陆坡以北向加拿大群岛移动的气旋相关的顺向风产生了深度增强的陆架流，并沿坡向东北流动。一个表面埃克曼在岸上的运输和相关的增加的海面高度的货架上产生一个横坡压力梯度，驱动一个沿斜坡东北正压流，在同一方向的风。与此相反，上升有利的风与深阿留申低气旋在阿拉斯加半岛和/或阿留申岛弧导致表面加强电流与沿斜坡向西流动。这种东北风产生了一个表面埃克曼传输，移动表面沃茨离岸。相关的横坡压力梯度驱动顺坡西南正压气流。由上升流和下降流产生的风驱动正压流叠加在背景底部加强的陆架流上。对于下沉流，这种流动放大了深度强化的背景斜压环流，增强了太平洋水输送到加拿大群岛。对于上升流，陆架断裂流是反向的，这导致在相反方向的表面强化流。这些结果得到了数值模拟的支持。
Pacific water contributes significantly to the Arctic Ocean freshwater budget. Recent increases in Arctic freshwater flux, also affected by the Pacific-derived Arctic water, impact the Atlantic overturning circulation with implications for global climate. The interannual variability of the Pacific water outflow remains poorly understood, partly due to different branches of the Pacific water flow in the Arctic Ocean. The shelfbreak current over the Beaufort Sea continental slope transports ~50% of the Pacific-derived water eastward along the Beaufort Sea continental slope towards the Canadian Archipelago. The oceanographic mooring deployed over the eastern Beaufort Sea continental slope in October 2003 recorded current velocities through depths of 28–108 m until September 2005. Data analysis revealed that these highly energetic currents have two different modes of depth-dependent behaviour. The downwelling-favourable wind associated with cyclones passing north of the Beaufort Sea continental slope toward the Canadian Archipelago generates depth-intensified shelfbreak currents with along-slope northeastward flow. A surface Ekman on-shore transport and associated increase of the sea surface heights over the shelf produce a cross-slope pressure gradient that drives an along-slope northeastward barotropic flow, in the same direction as the wind. In contrast, the upwelling-favourable wind associated with deep Aleutian Low cyclones over the Alaskan Peninsula and/or Aleutian Island Arc leads to surface-intensified currents with along-slope westward flow. This northeasterly wind generates a surface Ekman transport that moves surface waters offshore. The associated cross-slope pressure gradient drives an along-slope southwestward barotropic flow. The wind-driven barotropic flow generated by upwelling and downwelling is superimposed on the background bottom-intensified shelfbreak current. For downwelling, this flow amplifies the depth-intensified background baroclinic circulation with enhanced Pacific water transport towards the Canadian Archipelago. For upwelling, the shelfbreak current is reversed, which results in surface-intensified flow in the opposite direction. These results are supported by numerical simulations.
影响因子：
3.6
作者：
Timmermans, M. -L.;Proshutinsky, A.;Nishino, S.
通讯作者：
Nishino, S.