Is Labrador Sea Water formed in the Irminger basin?
Is Labrador Sea Water formed in the Irminger basin?
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DOI：
10.1016/s0967-0637(02)00134-6
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发表时间：
2003-01-01
影响因子：
2.4
通讯作者：
Moore, GWK
中科院分区：
文献类型：
--
作者：
Pickart, RS;Straneo, F;Moore, GWK
现今的观点认为，拉布拉多海水（LSW），北大西洋的主要水团之一，是完全在拉布拉多盆地通过深冬季对流形成的。本文认为，LSW可能形成于第二个位置-西南Irminger海。我们基于两个证据：（1）西副极地环流中的示踪剂观测与单一来源不一致，（2）导致拉布拉多海对流的海洋和大气条件的组合也存在于格陵兰岛以东。水文数据（包括最近的和气候），结合对流扩散数值模型，证明LSW的空间分布和推断的扩散率是不一致的拉布拉多海的唯一来源。扩展速度必须快得不切实际，而且不能产生在Irminger盆地观察到的LSW特性的极值。与此同时，一组必要的条件，深对流发生的预处理水柱，气旋环流，强大的空气-海洋浮力通量，在Irminger海得到满足。利用观测参数，混合层模式表明，在适当的条件下，翻转可以发生在Irminger海的深度为1500-2000米，形成LSW。(C)2003爱思唯尔科技有限公司版权所有。
Present day thinking contends that Labrador Sea Water (LSW), one of the major watermasses of the North Atlantic, is formed exclusively in the Labrador basin via deep wintertime convection. It is argued herein that LSW is likely formed at a second location-the southwest Irminger Sea. We base this on two pieces of evidence: (1) tracer observations in the western subpolar gyre are inconsistent with a single source and (2) the combination of oceanic and atmospheric conditions that lead to convection in the Labrador Sea is present as well east of Greenland. Hydrographic data (both recent and climatological) are used, in conjunction with an advective-diffusive numerical model, to demonstrate that the spatial distribution of LSW and its inferred spreading rate are inconsistent with a Labrador Sea-only source. The spreading would have to be unrealistically fast, and could not produce the extrema of LSW properties observed in the Irminger basin. At the same time, the set of conditions necessary for deep convection to occur-a preconditioned water column, cyclonic circulation, and strong air-sea buoyancy fluxes-are satisfied in the Irminger Sea. Using observed parameters, a mixed-layer model shows that, under the right conditions, overturning can occur in the Irminger Sea to a depth of 1500-2000 m, forming LSW. (C) 2003 Elsevier Science Ltd. All rights reserved.