Delayed responses of the oceanic Beaufort Gyre to winds and sea ice motions: influences on variations of sea ice cover in the Pacific sector of the Arctic Ocean
Delayed responses of the oceanic Beaufort Gyre to winds and sea ice motions: influences on variations of sea ice cover in the Pacific sector of the Arctic Ocean
复制标题
海洋波弗特环流对风和海冰运动的延迟响应：对北冰洋太平洋区海冰覆盖变化的影响
DOI：
10.1007/s10872-015-0276-6
复制
发表时间：
2015
影响因子：
2.3
通讯作者：
K. Chung
中科院分区：
文献类型：
--
作者：
E. Yoshizawa;K. Shimada;H. K. Ha;Tae Wan Kim;Sung;K. Chung
在2000年代后期，北冰洋的主要海冰类型从多年冰转变为一年冰。在这种情况下，第一年冰的冬季增长和融化开始时的冰厚度是海冰在接下来的夏天是否能够生存或消失的关键先决条件。增长率在很大程度上取决于上层海洋的热条件。在北冰洋的太平洋区，夏季太平洋暖水是影响海冰生长的主要热源，在风和海冰运动的驱动下，夏季太平洋暖水通过博福特环流向北冰洋输送，但博福特环流对海面强迫的响应时间尺度至今尚不清楚。在本研究中，我们研究的海洋动力高度附近的北风脊作为向北的体积运输和卷曲的风和海冰速度的代理之间的关系，使用多元回归模型，评估过去的表面强迫海洋博福特环流的当前状态的相对贡献。因此，2006-2012年海洋延迟响应的时间尺度估计约为3年。在考虑响应时间尺度的情况下，利用卫星海冰运动数据建立的多元回归模型成功地重建了观测到的海洋动力高度变化，其精度为0.2cm，相当于观测到的变化幅度的2%左右。
In the late 2000s, the dominant sea ice type in the Arctic Ocean changed from multi-year ice to first-year ice. In this condition, winter growth of first-year ice and resultant ice thickness at the melt onset are key preconditions on whether sea ice can survive or will disappear during the following summer. The growth rate strongly depends on upper ocean thermal conditions. In the Pacific sector of the Arctic Ocean, the warm Pacific Summer Water, which is a major heat source affecting the sea ice growth, is transported toward the basin by the oceanic Beaufort Gyre, driven by winds and sea ice motions, but the response time scale of the oceanic Beaufort Gyre to surface forcing has been unclear until now. In the present study, we examine the relationship between the ocean dynamic height near the Northwind Ridge as a proxy of the northward volume transport and curls of winds and sea ice velocities, using multiple regression models that evaluate relative contributions of past surface forcing to the current state of the oceanic Beaufort Gyre. As a result, the time scale of the delayed oceanic response in 2006–2012 was estimated to be about 3 years. Taking into account the response time scale, the multiple regression model using the satellite-derived sea ice motion data successfully reconstructed the observed variations of ocean dynamic heights within an accuracy of 0.2 dynamic cm, which corresponded to about 2 % of the amplitude of the observed variations.