A wind-driven, hybrid latent and sensible heat coastal polynya off Barrow, Alaska
A wind-driven, hybrid latent and sensible heat coastal polynya off Barrow, Alaska
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阿拉斯加巴罗附近的风力驱动、潜热和显热混合的沿海冰间湖
DOI：
10.1002/2015jc011318
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发表时间：
2016
影响因子：
--
通讯作者：
and T. Tamura
中科院分区：
文献类型：
--
作者：
Hirano;D.;Y. Fukamachi;E. Watanabe;K. I. Ohshima;K. Iwamoto;A. Mahoney;H. Eicken;D. Shimizu;and T. Tamura
巴罗海岸冰（BCP）的性质，这是在冬季形成的阿拉斯加海岸，使用系泊数据，大气再分析数据，和卫星派生的海冰浓度和生产数据进行检查。我们专注于海洋学条件，如水体分布和洋流结构下的BCP。2009年8月至2010年7月，在楚科奇海东北部的阿拉斯加州巴罗海域部署了两个系泊系统。对于12月至5月的海冰季节，已确定与BCP相关的五个事件的特征序列;（1）平行于巴罗峡谷的主导东北风，在巴罗附近有离岸成分，（2）海冰产量高，（3）BCP下方温暖和含盐的大西洋水的上涌，（4）与上涌引起的位移密度面相关的强烈向上峡谷剪切流，（5）冰生长的突然抑制。上升流后形成的斜压流结构，引起垂直切变的增强和相应的垂直混合。混合事件和开放水域的形成同时发生，一旦海冰的生产已经停止。因此，混合事件伴随着海洋热通量从涌升的温水进入表层，在开阔水域的形成/维持中发挥了重要作用（即，感热冰间湖）。高分辨率泛北极冰洋模式很好地再现了从潜热冰槽到感热冰槽的转变。我们认为，BCP，以前被认为是一个潜热冰穴，是一个风驱动的混合潜热和显热冰穴，这两个功能造成的相同的东北风。
The nature of the Barrow Coastal Polynya (BCP), which forms episodically off the Alaska coast in winter, is examined using mooring data, atmospheric reanalysis data, and satellite‐derived sea‐ice concentration and production data. We focus on oceanographic conditions such as water mass distribution and ocean current structure beneath the BCP. Two moorings were deployed off Barrow, Alaska in the northeastern Chukchi Sea from August 2009 to July 2010. For sea‐ice season from December to May, a characteristic sequence of five events associated with the BCP has been identified; (1) dominant northeasterly wind parallel to the Barrow Canyon, with an offshore component off Barrow, (2) high sea‐ice production, (3) upwelling of warm and saline Atlantic Water beneath the BCP, (4) strong up‐canyon shear flow associated with displaced density surfaces due to the upwelling, and (5) sudden suppression of ice growth. A baroclinic current structure, established after the upwelling, caused enhanced vertical shear and corresponding vertical mixing. The mixing event and open water formation occurred simultaneously, once sea‐ice production had stopped. Thus, mixing events accompanied by ocean heat flux from the upwelled warm water into the surface layer played an important role in formation/maintenance of the open water area (i.e., sensible heat polynya). The transition from a latent to a sensible heat polynya is well reproduced by a high‐resolution pan‐Arctic ice‐ocean model. We propose that the BCP, previously considered to be a latent heat polynya, is a wind‐driven hybrid latent and sensible heat polynya, with both features caused by the same northeasterly wind.