A Change of Seasonality of the Upper Arctic Ocean in Response to Atmospheric and Sea-ice Forcing

该奖项是根据《2009年美国复苏和再投资法》(公法111-5)资助的。该协会建议调查北冰洋埃克曼输送和上升流/下降流的季节性变化，以及它们与北极系统关键组成部分的关系。需要对北冰洋上升流及其季节性变化进行系统调查，以便了解快速变化的北极系统各组成部分之间的复杂相互作用。上升流可以说是海洋学中唯一最重要的动力变量。它迫使大洋涡旋通过斯维德鲁普天平。上升流补充了表层的营养物质，有助于维持浮游植物的生产。它是从北冰洋温暖的大西洋水层向混合层输送热通量的管道，影响着海冰热力学和大气环流。上升流和埃克曼输运影响表层盐度，从而在海洋温盐环流中发挥作用。最强烈的上升流发生在北极海岸，因此上升流季节性的变化会影响陆地过程，例如近岸沉积物中的永久冻土。利用卫星和浮标观测估计了1979年至2006年期间每天的埃克曼输送和上升流。该数据集将在该项目的第一年进行更新、验证并向社区提供。PI将量化Ekman层的季节性变化，并研究它们与海冰覆盖率下降和振荡气候模式(如北极涛动)的关系。研究上升流的季节性变化对叶绿素浓度、混合层温度和盐度的影响。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The PI proposes to investigate the change of seasonality of the Arctic Ocean Ekman transport and upwelling/downwelling, and their relationships to key components of the Arctic System. A systematic investigation of the Arctic Ocean upwelling and its change of seasonality is needed in order to understand complex interactions among components of a rapidly changing Arctic System. Upwelling is arguably the single most important dynamical variable in oceanography. It forces oceanic gyres through the Sverdrup balance. Upwelling replenishes nutrients in the surface layer and helps to sustain phytoplankton production. It is a conduit for heat flux from the warm Atlantic Water layer of the Arctic Ocean to the mixed layer, where it influences the sea ice thermodynamics and the atmospheric circulation. Upwelling and Ekman transport affect the surface salinity and thus play roles in the oceanic thermohaline circulation. The most intense upwelling occurs along the Arctic coast, so a change of upwelling seasonality can influence land processes, such as the permafrost in nearshore sediments. Daily Ekman transport and upwelling from 1979 to 2006 have been estimated using satellite and buoy observations. This dataset will be updated, validated and made available to the community in the first year of this project. The PI will quantify the changes in seasonality of the Ekman layer, and examine how they are related to the decline in sea-ice cover and to oscillatory climate modes (such as the Arctic Oscillation). The impacts of the changes in seasonality of upwelling on the chlorophyll concentration, mixed-layer temperature and salinity will be examined.