Subpolar North Atlantic Overturning and Gyre-Scale Circulation in the Summers of 2014 and 2016
Subpolar North Atlantic Overturning and Gyre-Scale Circulation in the Summers of 2014 and 2016
复制标题
DOI：
10.1029/2018jc013841
复制
发表时间：
2018-07-01
影响因子：
3.6
通讯作者：
Mcdonagh, E. L.
中科院分区：
文献类型：
--
作者：
Holliday, N. P.;Bacon, S.;Mcdonagh, E. L.
大西洋经向翻转环流（AMOC）是全球气候系统的一个重要组成部分，它通过输送热量和淡水而发挥作用。副极地北大西洋（SPNA）是一个区域，其中AMOC是积极发展和成型，通过混合和水团的转换和大量的热量释放到大气中。2014年和2016年夏季的两个水文跨流域部分提供了从加拿大到格陵兰岛到苏格兰的SPNA速度和属性场的高度空间分辨率视图。AMOC，等密度线（涡旋尺度）运输，热量和淡水运输的估计来自观测。翻转环流是从地表到海底的向北输送的最大值，在密度空间中计算，范围很大，2014年6月至7月为20.6 +/- 4.7 Sv，2016年5月至8月为10.6 +/- 4.3 Sv。相比之下，2014年夏季的等密度环流最低：41.3 +/- 8.2 Sv，而2016年为58.6 +/- 7.4 Sv。热量输送（2014年夏季为0.39 +/- 0.08 PW，正向北）在AMOC最高的断面最高，淡水输送在2016年夏季等密度环流高（-0.25 +/- 0.08 Sv）时最大。高达65%的热量和淡水运输进行的等密度环流，与等密度属性运输最高的拉布拉多海西部和东部盆地（冰岛盆地苏格兰）。
The Atlantic Meridional Overturning Circulation (AMOC) is a key component of the global climate system through its transport of heat and freshwater. The subpolar North Atlantic (SPNA) is a region where the AMOC is actively developed and shaped though mixing and water mass transformation and where large amounts of heat are released to the atmosphere. Two hydrographic transbasin sections in the summers of 2014 and 2016 provide highly spatially resolved views of the SPNA velocity and property fields on a line from Canada to Greenland to Scotland. Estimates of the AMOC, isopycnal (gyre-scale) transport, and heat and freshwater transport are derived from the observations. The overturning circulation, the maximum in northward transport integrated from the surface to seafloor and computed in density space, has a high range, with 20.6 +/- 4.7 Sv in June-July 2014 and 10.6 +/- 4.3 Sv in May-August 2016. In contrast, the isopycnal (gyre-scale) circulation was lowest in summer 2014: 41.3 +/- 8.2 Sv compared to 58.6 +/- 7.4 Sv in 2016. The heat transport (0.39 +/- 0.08 PW in summer 2014, positive is northward) was highest for the section with the highest AMOC, and the freshwater transport was largest in summer 2016 when the isopycnal circulation was high (-0.25 +/- 0.08 Sv). Up to 65% of the heat and freshwater transport was carried by the isopycnal circulation, with isopycnal property transport highest in the western Labrador Sea and the eastern basins (Iceland Basin to Scotland).