Seasonal variability of water masses and transport on the Antarctic continental shelf and slope in the southeastern Weddell Sea
Seasonal variability of water masses and transport on the Antarctic continental shelf and slope in the southeastern Weddell Sea
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DOI：
10.1002/jgrc.20174
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发表时间：
2013-04-01
影响因子：
3.6
通讯作者：
Holland, Paul R.
中科院分区：
文献类型：
--
作者：
Graham, Jennifer A.;Heywood, Karen J.;Holland, Paul R.
从2009年2月至2010年2月，在南极大陆架和威德尔海东南部的斜坡（西经18度）部署了五个系泊装置。观测结果表明了造成该区域水团和运输变化的关键过程。全年温度和盐度的快速波动与阵列上风应力的变化有关。这导致了密度跃层的加深或变浅，超过了系泊的深度。在上500米，在盐度的季节性循环显示，在秋季，最强的淡化在最浅的停泊（250米），最远的货架上。在此期间，阵列上的海冰浓度超过90%，并在秋季向海洋提供正的盐通量。2009年4月下旬，在强烈的沿岸（东风）风期间开始出现清新。这表明，埃克曼运输和风驱动的混合的变化在确定南极洲周围大陆架沃茨的盐度方面发挥着关键作用。南极斜坡流的运输也表现出季节性的循环，在4月下旬达到最大值。模型模拟显示沿岸平流的重要性，因为来自上游的新鲜异常的到来决定了阵列处盐度最小值的时间。这些过程可能对南极大陆周围的其他地区很重要。
An array of five moorings was deployed from February 2009 to February 2010 across the Antarctic shelf and slope in the southeastern Weddell Sea (18 degrees W). Observations demonstrate the key processes responsible for variability in water masses and transport in the region. Rapid fluctuations in temperature and salinity throughout the year are linked with variability in wind stress over the array. This causes the deepening or shoaling of the pycnocline, past the depth of the moorings. In the upper 500 m, the seasonal cycle in salinity shows freshening in autumn, with the strongest freshening at the shallowest mooring (250 m), furthest on-shelf. The sea ice concentration over the array exceeds 90% during this period and contributes a positive salt flux into the ocean during autumn. Freshening begins during strong along-shore (easterly) winds in late April 2009. This demonstrates that variations in Ekman transport and wind-driven mixing play a key role in determining the salinity of shelf waters around Antarctica. Transport of the Antarctic Slope Current also shows a seasonal cycle with a maximum during late April. Model simulations show the importance of along-shore advection, as the arrival of a fresh anomaly from upstream determines the timing of the salinity minimum at the array. These processes are likely to be important for other regions around the Antarctic continent.