Current variability under landfast sea ice in Lützow‐Holm Bay, Antarctica
Current variability under landfast sea ice in Lützow‐Holm Bay, Antarctica
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南极洲吕佐夫-霍尔姆湾陆地海冰下的电流变化
DOI：
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发表时间：
2000
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影响因子：
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通讯作者：
Takuya Miyakawa
中科院分区：
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作者：
K. Ohshima;T. Kawamura;T. Takizawa;S. Ushio;Takuya Miyakawa
1991年在南极洲吕佐夫 - 霍尔姆湾的固定海冰下进行了海流测量。尽管没有直接的风力作用且热盐力作用可忽略不计，但观测到了幅度为0.1 - 0.3米/秒的海流。研究表明，海流的变化在很大程度上取决于向东的大陆架上固定冰的范围。在固定冰边缘延伸到陆架坡折之前，位于大陆海岸附近的翁古尔海峡的海流与风在1 - 1.5天的时间滞后上高度相干，并且在6 - 8天的周期内与调整后的海平面在无时间滞后的情况下有一定的相干性。在固定冰边缘稳定地位于陆架坡折之后，海流与风或海平面完全不相干。我们推断，6 - 8天周期的变化主要是由于向东的大陆架上的风应力激发的一阶陆架波引起的。尽管盛行风向没有改变，但翁古尔海峡的盛行海流方向在5月从向南（与风的方向相同）急剧转变为向北。这种时间上的变化与固定冰范围的快速发展期相吻合。
Current measurements were made under landfast sea ice in Lutzow-Holm Bay, Antarctica, in 1991. In spite of no direct wind forcing and negligible thermohaline forcing, currents with a magnitude of 0.1–0.3 m s−1 were observed. It is suggested that current variability strongly depends on the extent of the landfast ice on the eastward continental shelf. Before the fast ice edge extends to the shelf break the current at Ongul Strait, located near the continental coast, is highly coherent with the wind with a time lag of 1–1.5 days and somewhat coherent with the adjusted sea level with no time lag at periods of 6–8 days. After the fast ice edge is stably located along the shelf break the current is not at all coherent with the wind or sea level. We infer that the variability at periods of 6–8 days is mainly due to the first-mode shelf wave excited by the wind stress over the eastward continental shelf. The direction of the prevailing current at Ongul Strait changed drastically from southward (the same direction of the wind) to northward in May, although the prevailing wind direction did not change. This change in timing coincides with the rapid development period of the fast ice extent.