The Beaufort Gyre Extent, Shape, and Location Between 2003 and 2014 From Satellite Observations
The Beaufort Gyre Extent, Shape, and Location Between 2003 and 2014 From Satellite Observations
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DOI：
10.1029/2018jc014379
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发表时间：
2019-02
期刊：
影响因子：
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通讯作者：
H. Regan;C. Lique;T. Armitage
中科院分区：
文献类型：
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作者：
H. Regan;C. Lique;T. Armitage
波弗特环流是北极重要的淡水水库。它被认为在调节北极淡水向北大西洋的排放方面发挥着关键作用，近几十年来，在北极快速变化的时期，其淡水含量有所增加。尽管如此，其确切的动力学行为尚未完全了解。在这里，我们利用整个北极范围内的动态海洋地形数据集（包括海冰下的数据）来描述波弗特环流随时间变化的范围、形状和位置。我们发现，2003 年至 2014 年间，环流向西北方向扩展，导致 2014 年更加接近楚科奇高原和门捷列夫海岭。我们发现，环流强度和最大动态海洋地形都容易响应表面强迫强度的变化，但环流面积还受到波弗特海高压位置的影响。这导致楚科奇高原扩张，并增加了环流的不对称性，因为它受到浅水深的限制。环流强度与过去 3 个月海洋的综合表面应力相关。我们讨论了浅水深测量的扩展对环流动力学行为的影响以及对加拿大盆地物理性质的潜在影响。简单语言摘要 波弗特环流位于北冰洋的加拿大盆地，蕴藏着北极地区淡水总量的大量，被认为对于控制淡水出口到北大西洋非常重要，从而影响那里的海洋学。最近，环流中的淡水有所增加，但环流本身以及这种变化的影响尚不清楚。我们使用卫星数据集来详细描述环流的大小、形状和位置，以及它在 2003 年至 2014 年期间的变化。我们发现，当风力增强时，环流环流增加，响应延迟3个月。风的空间分布也会影响环流的位置和形状。环流向西北方向扩展，直到达到浅水深，这限制了自由扩展并导致其形状变得不对称。我们讨论了这对环流循环和淡水储存的潜在影响，以及对周围海洋的影响。
The Beaufort Gyre is a significant reservoir of freshwater in the Arctic. It is thought to play a key role in regulating Arctic freshwater discharge to the North Atlantic, and in recent decades its freshwater content has increased in a time of rapid Arctic change. Despite this, its exact dynamical behavior is not fully understood. Here, we make use of an Arctic-wide dataset of dynamic ocean topography, including data under sea ice, to characterize the time-varying extent, shape, and location of the Beaufort Gyre. We show that the gyre expanded toward the northwest between 2003 and 2014, resulting in increased proximity to the Chukchi Plateau and Mendeleev Ridge by 2014. We find that the gyre strength and maximum dynamic ocean topography both respond readily to changes in intensity of the surface forcing, but the gyre area is additionally affected by the location of the Beaufort Sea High. This results in expansion over the Chukchi Plateau and increased asymmetry of the gyre as it becomes constrained by the shallow bathymetry. The gyre strength is correlated with the integrated surface stress on the ocean over the previous 3 months. We discuss the implications of the expansion over shallow bathymetry on gyre dynamical behavior and the potential impacts on the physical properties in the Canada Basin. Plain Language Summary The Beaufort Gyre, in the Canadian Basin of the Arctic Ocean, contains a large amount of the total freshwater held in the Arctic and is thought to be important in controlling freshwater exported out into the North Atlantic and thus affects the oceanography there. Recently, the freshwater in the gyre has increased, but the gyre itself and the effect of this change are not well understood. We use a satellite dataset to describe, in detail, the size, shape, and position of the gyre, and how it changed over 2003–2014. We found that the gyre circulation increases when winds strengthen, with a delayed response of 3 months. The spatial distribution of the wind also affects the position and shape of the gyre. The gyre expanded toward the northwest until it reached shallow bathymetry, which limited free expansion and caused its shape to become asymmetrical. We discuss the potential effects of this on the gyre's circulation and freshwater storage, as well as impacts on the surrounding ocean.