The Atlantic Water (AW) inflow through Fram Strait, largest oceanic heat source to the Arctic Ocean, undergoes substantial modifications in the Western Nansen Basin (WNB). Evaluation of the Mercator system in the WNB, using 1,500 independent temperature‐salinity profiles and five years of mooring data, highlighted its performance in representing realistic AW inflow and hydrographic properties. In particular, favorable comparisons with mooring time‐series documenting deep winter mixed layers and changes in AW properties led us to examine winter conditions in the WNB over the 2007–2020 period. The model helped describe the interannual variations of winter mixed layers and documented several processes at stake in modifying AW beyond winter convection: trough outflows and lateral exchange through vigorous eddies. Recently modified AW, either via local convection or trough outflows, were identified as homogeneous layers of low buoyancy frequency. Over the 2007–2020 period, two winters stood out with extreme deep mixed layers in areas that used to be ice‐covered: 2017/18 over the northern Yermak Plateau‐Sofia Deep; 2012/13 on the continental slope northeast of Svalbard with the coldest and freshest modified AW of the 12‐year time series. The northern Yermak Plateau‐Sofia Deep and continental slope areas became “Marginal Convection Zones” in 2011 with, from then on, occasionally ice‐free conditions, 50‐m‐ocean temperatures always above 0 °C and highly variable mixed layer depths and ocean‐to‐atmosphere heat fluxes. In the WNB where observations require considerable efforts and resources, the Mercator system proved to be a good tool to assess Atlantic Water modifications in winter.

中文翻译：

---

墨卡托物理系统从2007年到2020年在斯瓦尔巴群岛以北的大西洋水改造

通过南北冰洋最大的海洋热源弗拉姆海峡流入的大西洋水（AW）在南森盆地（WNB）进行了重大改造。对WNB中的Mercator系统的评估，使用了1500个独立的温度盐度剖面和五年的系泊数据，突出了其在代表现实的AW流入量和水文特性方面的性能。特别是，与记录深冬季混合层和AW特性变化的系泊时间序列的有利比较使我们研究了WNB在2007–2020年期间的冬季条件。该模型有助于描述冬季混合层的年际变化，并记录了在冬季对流以外改变AW的几个关键过程：槽外流和通过剧烈涡旋进行的横向交换。最近修改的AW，通过局部对流或水槽流出，被确定为低浮力频率的均质层。在2007年至2020年期间，两个曾经在被冰雪覆盖的地区形成极深混合层的冬季：2017/18年度，Yermak高原北部至索非亚深处；2012/13年，在斯瓦尔巴群岛东北部的大陆斜坡上，这是12年时间序列中最冷，最新鲜的改良AW。Yermak高原北部-索非亚深部和大陆斜坡地区在2011年成为“边缘对流区”，此后偶尔无冰，50 m海洋温度始终高于0°C，并且混合层深度和海洋变化很大到大气的热通量。在观测需要大量努力和资源的WNB中，墨卡托系统被证明是评估冬季大西洋水质变化的好工具。