Observed Atlantification of the Barents Sea Causes the Polar Front to Limit the Expansion of Winter Sea Ice
Observed Atlantification of the Barents Sea Causes the Polar Front to Limit the Expansion of Winter Sea Ice
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DOI：
10.1175/jpo-d-18-0003.1
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发表时间：
2018-08-01
影响因子：
3.5
通讯作者：
Lique, Camille
中科院分区：
文献类型：
--
作者：
Barton, Benjamin I.;Lenn, Yueng-Djern;Lique, Camille
巴伦支海水(BSW)是由大西洋水形成的，大西洋水通过大气热损失冷却，并通过季节性海冰融化而新鲜。在巴伦支海东部，BSW和更新鲜、更冷的北极水沿着极锋(PF)在海面相遇。尽管PF在设定BSW通风的北部极限方面很重要，但它的记录一直很少，大多躲过了避免季节性海冰的观测调查的检测。在这项研究中，除了温度和盐度气候学外，还利用卫星海洋表面温度(SST)观测来检查PF的位置和结构，并描述其在1985-2016年期间的变化。结果表明，Pf与海冰边缘位置无关，是位涡约束下的陆架坡流。SST年际变化的主要驱动因素是大西洋水温的变化，自2005年以来，大西洋水温显著增加。与PF相关的海温梯度在2005年后也有所增加，防止了近年来冬季海冰在锋面以南延伸。PF南部新鲜的季节性海冰融化的消失导致了BSW盐度和密度的显著增加。由于北冰洋中温带形成了北冰洋中层水的大部分，北冰洋中温带特性的变化可能会对北冰洋环流和气候产生深远影响。
Barents Sea Water (BSW) is formed from Atlantic Water that is cooled through atmospheric heat loss and freshened through seasonal sea ice melt. In the eastern Barents Sea, the BSW and fresher, colder Arctic Water meet at the surface along the Polar Front (PF). Despite its importance in setting the northern limit of BSW ventilation, the PF has been poorly documented, mostly eluding detection by observational surveys that avoid seasonal sea ice. In this study, satellite sea surface temperature (SST) observations are used in addition to a temperature and salinity climatology to examine the location and structure of the PF and characterize its variability over the period 1985-2016. It is shown that the PF is independent of the position of the sea ice edge and is a shelf slope current constrained by potential vorticity. The main driver of interannual variability in SST is the variability of the Atlantic Water temperature, which has significantly increased since 2005. The SST gradient associated with the PF has also increased after 2005, preventing sea ice from extending south of the front during winter in recent years. The disappearance of fresh, seasonal sea ice melt south of the PF has led to a significant increase in BSW salinity and density. As BSW forms the majority of Arctic Intermediate Water, changes to BSW properties may have far-reaching impacts for Arctic Ocean circulation and climate.