Mechanisms for the variation of sea ice extent in the northern hemisphere
Mechanisms for the variation of sea ice extent in the northern hemisphere
复制标题
北半球海冰范围变化机制
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
M. Wakatsuchi
中科院分区：
文献类型：
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作者：
N. Kimura;M. Wakatsuchi
利用星载海冰资料和大气资料，研究了控制北方海冰范围变化的过程。利用1991/1992 ~ 1997/1998年7个冬季（12 ~ 4月）的美国国防气象卫星计划（DMSP）专用传感器微波成像仪（SSM/I）图像，采用最大互相关法计算了日冰运动场。为了研究冰的范围的时间变化的机制，我们分析了50个指定的线在日常的冰边缘。虽然在所有的冰缘地区，冰的运动和地转风速之间的相关性很高，冰缘位移的速度和风速之间的相关程度与区域不同。冰缘速度对风速的响应程度主要取决于冰缘速度对冰运动的响应程度。预计控制北方各区域冰量变化的机制如下。在巴伦支海、白令海和鄂霍次克海，冰度的推进主要是由风驱动的冰平流推动的，冰度的日尺度变化也受风速变化的控制。相比之下，拉布拉多海和格陵兰海的冰的范围似乎是相当大的海洋学因素的影响，如热锋的位置，并没有相关的风速的变化。变化机制的区域差异也反映在最大冰幅的年际变化上。
Using daily sea ice data derived from satellite-borne sensors and atmospheric data, we examined processes controlling the variation of sea ice extent in the Northern Hemisphere. The daily ice motion field was computed from imagery of the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSM/I) for seven winters (December to April) from 1991/1992 to 1997/1998, by employing the maximum cross-correlation method. In order to examine mechanisms of the temporal variation of the ice extent, we analyzed 50 specified lines across the daily ice edge. Although a high correlation between the ice motion and the geostrophic wind speed was observed in all the ice edge areas, the degree for correlation between the speed of the ice edge displacement and the wind speed varied with region. The degree for response of the ice edge speed to the wind speed largely depended upon that of the ice edge speed to the ice motion. The following mechanisms controlling the variation of ice extent for regions in the Northern Hemisphere were anticipated. In the Barents Sea, Bering Sea, and the Sea of Okhotsk the ice extent advances by wind-driven ice advection and the daily scale variation of the ice extent were also controlled by the variation in wind speed. In contrast, the ice extent in the Labrador Sea and the Greenland Sea seemed to be considerably affected by oceanographic factors such as the location of the thermal front and was not related to the variation in wind speed. The regional difference of the variation mechanism was also reflected in the interannual variation in maximum ice extent.