Impact of the Arctic Ocean Atlantic water layer on Siberian shelf hydrography
Impact of the Arctic Ocean Atlantic water layer on Siberian shelf hydrography
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DOI：
10.1029/2009jc006020
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发表时间：
2010-08-07
影响因子：
3.6
通讯作者：
Schroeder, David
中科院分区：
文献类型：
--
作者：
Dmitrenko, Igor A.;Kirillov, Sergey A.;Schroeder, David
本文探讨了北冰洋大西洋水（AW）的作用，在修改拉普捷夫海陆架底部水文的基础上，从1932年至2008年的历史记录，在2008年4月至5月进行的实地观测，和2002年至2009年的横坡测量。海底水文气候学表明，从30-50米深度等值线延伸到近海的变暖。底层温度时间序列构建的历史记录链接的拉普捷夫海外大陆架AW边界电流输送温暖和盐水从北大西洋。1990年代中期和2000年代中期的AW变暖与外大陆架底部温度的变化是一致的。对于2008年4月至5月，我们观察到大陆架近底温暖和盐水入侵到20米等深线。这些侵入物通常比环境水高0.2摄氏度，咸度高1-1.5个实际盐度单位。2002-2009年的横坡观测表明，大陆坡向上的热通量从AW到上覆的低盐跃层水（LHW）。LHW的横向大陆架风驱动的运输，然后在底层记录在拉普捷夫海大陆架的温盐异常的结果。我们还发现，冰间层引起的垂直混合可能作为底层的排水，允许一个相对较小的部分AW热量直接释放到大气中。最后，我们看到在历史记录中，拉普捷夫海陆架深度超过10-15米的地方没有明显的变暖（到目前为止）。然而，未来的气候变化可能会带来更多的入侵的南极改性沃茨与潜在的温暖的温度到大陆架上，这可能会对海上海底永久冻土的稳定性产生重大影响。
This paper examines the role of the Arctic Ocean Atlantic water (AW) in modifying the Laptev Sea shelf bottom hydrography on the basis of historical records from 1932 to 2008, field observations carried out in April-May 2008, and 2002-2009 cross-slope measurements. A climatology of bottom hydrography demonstrates warming that extends offshore from the 30-50 m depth contour. Bottom layer temperature-time series constructed from historical records links the Laptev Sea outer shelf to the AW boundary current transporting warm and saline water from the North Atlantic. The AW warming of the mid-1990s and the mid-2000s is consistent with outer shelf bottom temperature variability. For April-May 2008 we observed on-shelf near-bottom warm and saline water intrusions up to the 20 m isobath. These intrusions are typically about 0.2 degrees C warmer and 1-1.5 practical salinity units saltier than ambient water. The 2002-2009 cross-slope observations are suggestive for the continental slope upward heat flux from the AW to the overlying low-halocline water (LHW). The lateral on-shelf wind-driven transport of the LHW then results in the bottom layer thermohaline anomalies recorded over the Laptev Sea shelf. We also found that polynya-induced vertical mixing may act as a drainage of the bottom layer, permitting a relatively small portion of the AW heat to be directly released to the atmosphere. Finally, we see no significant warming (up until now) over the Laptev Sea shelf deeper than 10-15 m in the historical record. Future climate change, however, may bring more intrusions of Atlantic-modified waters with potentially warmer temperature onto the shelf, which could have a critical impact on the stability of offshore submarine permafrost.