The interannual variability of the surface eddy kinetic energy in the Labrador Sea
The interannual variability of the surface eddy kinetic energy in the Labrador Sea
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DOI：
10.1016/j.pocean.2011.01.006
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发表时间：
2011-11
影响因子：
4.1
通讯作者：
Hao Luo;A. Bracco;E. Lorenzo
中科院分区：
文献类型：
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作者：
Hao Luo;A. Bracco;E. Lorenzo
利用一个区域海洋模式，通过数值积分研究了拉布拉多海表层涡动动能（EKE）的变化。在1980-2001年期间进行模拟，并与过去9年的卫星观测进行比较。在盆地的表面EKE模式占主导地位的区域沿着格陵兰西海岸的涡流，主要是反气旋，形成的不稳定的主要电流流过大陆坡，与以前的理想化的结果。在这里，年际变化与作为边界条件施加到模式域的传入边界流系统的剪切有关。简单海洋资料同化（SODA）再分析结果表明，东格陵兰海流在东北边界处的强度变化很大，对涡旋的形成有很大影响。在拉布拉多海中心，深对流发生，一个统计上显着的部分模拟的年际地面EKE变率与当地的大气强迫相关，热和风通量起着重要的作用，并可以采用作为预测的滞后2- 3个月。北极涛动指数也可用作大气通量的远程指示器，但与当地测量相比，技术较低。相反，北大西洋涛动指数在季节内和年际尺度上与地面EKE没有显着的相关性。在1993年至2001年的高度计数据的分析支持存在这种不对称的制度，本地强迫大气在中央盆地，和制度远程强迫沿沿着西格陵兰海岸的传入边界流。这些结果对监测和预报拉布拉多海表层涡动动能变率具有重要意义。
The variability of the surface eddy kinetic energy (EKE) in the Labrador Sea is investigated with a suite of numerical integrations using a regional ocean model. Simulations are performed over the period 1980–2001 and are compared to satellite observations over the last 9 years. The surface EKE pattern in the basin is dominated by a region along the West coast of Greenland where eddies, mainly anticyclonic, are formed by instability of the main currents flowing over the continental slope, consistent with previous idealized results. Here the interannual changes are linked to the shear of the incoming boundary current system imposed as boundary condition to the model domain. The highly variable strength of the East Greenland current at the northeast boundary, derived from the Simple Ocean Data Assimilation (SODA) reanalysis, strongly influences the vortex formation. In the center of the Labrador Sea, where deep convection occurs, a statistically significant portion of the modeled interannual surface EKE variability is correlated with the local atmospheric forcing, and both heat and wind fluxes play an important role and can be adopted as predictors at a lag of 2–3months. The Arctic Oscillation index can also be used as a remote indicator of the atmospheric fluxes, but with lower skill than local measurements. In contrast the North Atlantic Oscillation index does not correlate significantly with the surface EKE at intraseasonal and interannual scales. The analysis of altimeter data over the 1993–2001 supports the existence of this asymmetry between the regime locally forced by the atmosphere in the central basin, and the regime remotely forced by the incoming boundary current along the west Greenland coast. Those results have important implications for monitoring and predicting the surface eddy kinetic energy variability in the Labrador Sea.