A Simple Shelf Circulation Model: Intrusion of Atlantic Water on the West Spitsbergen Shelf
A Simple Shelf Circulation Model: Intrusion of Atlantic Water on the West Spitsbergen Shelf
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DOI：
10.1175/jpo-d-15-0058.1
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发表时间：
2016-04-01
影响因子：
3.5
通讯作者：
Inall, Mark
中科院分区：
文献类型：
--
作者：
Nilsen, Frank;Skogseth, Ragnheid;Inall, Mark
根据标准地转理论，发现了沿深度等值线的正压流动。建立了一个数值模型来研究这种流动的偏差。该模式较好地模拟了西斯皮茨卑尔根陆架(WSS)上的动力过程，并表明西斯皮茨卑尔根流(WSC)是大西洋水(AW)流向北极的主要通道，它比大陆架上的任何其他地方更容易与Isfjorden槽相连。沿西太平洋低谷的AW环流在这里被称为斯匹次卑尔根海流(STC)。从水文和洋流观测可以明显看出，STC主要是正压的，并受海面高度的驱动。建立了沿海风应力与STC之间的联系，论证了弗拉姆海峡1-2月冬季气旋增多是如何加速和扩大WSC的。最终，这将导致STC的加强和AW在WSS上的主导地位。STC代表了冬季AW向北冰洋较慢的路线和向西Spitsbergen峡湾的大量热量输送(向Isfjorden方向0.2-0.4TW)。热通量估计显示，伊斯福约登海槽中AW热损失的一半是由于热损失到周围的水团，其余的损失到大气中。自2006年以来，在一些峡湾，西斯皮茨卑尔根沿岸的海冰产量已经减少，甚至根本不存在。在这里，作者认为这是冬季WSS沿线强劲的南风周期的结果。
Barotropic flow along depth contours is found in accordance with standard geostrophic theory. A numerical model is developed that studies the deviation from such a flow. The model gives a good approximation of the dynamical processes on the West Spitsbergen Shelf (WSS) and shows that the West Spitsbergen Current (WSC), the main gateway of Atlantic water (AW) toward the Arctic, connects more easily to the Isfjorden Trough than anywhere else along the shelf. The circulation of AW in the troughs along the WSS is here named the Spitsbergen Trough Current (STC). From hydrographical and ocean current observations it is evident that the STC is primarily barotropic and driven by the sea surface height. A connection between the along-coast wind stress and the STC is established, and it is demonstrated how the increased occurrence of winter cyclones in Fram Strait during January-February accelerates and widens the WSC. Ultimately, this results in a strengthened STC and dominance of AW on the WSS. The STC represents a slower route of AW toward the Arctic Ocean and a large heat transport toward the West Spitsbergen fjords during winter (0.2-0.4 TW toward Isfjorden). Heat flux estimates show that half of the AW heat loss in the Isfjorden Trough is due to heat loss to the surrounding water masses, while the rest is lost to the atmosphere. Sea ice production along West Spitsbergen has been reduced, or even nonexistent, in some fjords since 2006. Here, the authors argue that this is a consequence of the strong southerly wind periods along the WSS during winter.