Sea ice and the ocean mixed layer over the Antarctic shelf seas
Sea ice and the ocean mixed layer over the Antarctic shelf seas
复制标题
DOI：
10.5194/tc-8-761-2014
复制
发表时间：
2014-01-01
期刊：
影响因子：
5.2
通讯作者：
Feltham, D. L.
中科院分区：
文献类型：
--
作者：
Petty, A. A.;Holland, P. R.;Feltham, D. L.
海洋混合层模式已被纳入洛斯阿拉莫斯海冰模式CICE，以调查南极大陆架沃茨表面驱动形成的区域变化。该模型很好地捕捉了预期的海冰厚度分布，并在威德尔和罗斯陆架海每年冬季产生深（>500米）的混合层。这导致在南部沿海深水区的水柱完全分层，导致高盐度陆架水（HSSW）的形成，也在这些海洋的一些较浅的地区（没有HSSW形成）。在阿蒙森海和别林斯高晋海产生较浅的混合层。通过解构驱动混合层深度演变的表面过程，我们表明，海冰生长/融化的净盐通量主导了混合层在所有地区的演变，从表面热通量的贡献较小，风应力的输入可以忽略不计。威德尔和罗斯陆架海收到每年盈余的混合能量在表面上的阿蒙森陆架海能量输入在秋季/冬季平衡的能量提取在春季/夏季和Bellingshausen陆架海经历了每年的表面能量赤字，通过在秋季/冬季的低能量输入和春季/夏季的最高能量损失。对海冰质量平衡的分析表明，每个区域的平均冰增长、融化和输出情况截然不同。威德尔和罗斯陆架海的年冰增长率最高，每年有很大一部分向北出口，而别林斯高晋陆架海的年冰融化率最高，这是由东北部的冰平流驱动的。进行线性回归分析，以确定秋季/冬季混合层加深和几个大气变量之间的联系。威德尔和罗斯陆架海显示出较强的空间相关性（时间平均区域内变异）之间的秋/冬混合层加深和几个大气变量相比，阿蒙森和别林斯高晋。相比之下，阿蒙森和别林斯高晋陆架海表现出较强的时间相关性（陆架海平均年际变化）之间的秋/冬混合层加深和几个大气变量。
An ocean mixed-layer model has been incorporated into the Los Alamos sea ice model CICE to investigate regional variations in the surface-driven formation of Antarctic shelf waters. This model captures well the expected sea ice thickness distribution, and produces deep (>500 m) mixed layers in the Weddell and Ross shelf seas each winter. This results in the complete destratification of the water column in deep southern coastal regions leading to high-salinity shelf water (HSSW) formation, and also in some shallower regions (no HSSW formation) of these seas. Shallower mixed layers are produced in the Amundsen and Bellingshausen seas. By deconstructing the surface processes driving the mixed-layer depth evolution, we show that the net salt flux from sea ice growth/melt dominates the evolution of the mixed layer in all regions, with a smaller contribution from the surface heat flux and a negligible input from wind stress. The Weddell and Ross shelf seas receive an annual surplus of mixing energy at the surface; the Amundsen shelf sea energy input in autumn/winter is balanced by energy extraction in spring/summer; and the Bellingshausen shelf sea experiences an annual surface energy deficit, through both a low energy input in autumn/winter and the highest energy loss in spring/summer. An analysis of the sea ice mass balance demonstrates the contrasting mean ice growth, melt and export in each region. The Weddell and Ross shelf seas have the highest annual ice growth, with a large fraction exported northwards each year, whereas the Bellingshausen shelf sea experiences the highest annual ice melt, driven by the advection of ice from the northeast. A linear regression analysis is performed to determine the link between the autumn/winter mixed-layer deepening and several atmospheric variables. The Weddell and Ross shelf seas show stronger spatial correlations (temporal mean - intra-regional variability) between the autumn/winter mixed-layer deepening and several atmospheric variables compared to the Amundsen and Bellingshausen. In contrast, the Amundsen and Bellingshausen shelf seas show stronger temporal correlations (shelf sea mean interannual variability) between the autumn/winter mixed-layer deepening and several atmospheric variables.