Arctic Ocean and Hudson Bay Freshwater Exports: New Estimates from Seven Decades of Hydrographic Surveys on the Labrador Shelf
Arctic Ocean and Hudson Bay Freshwater Exports: New Estimates from Seven Decades of Hydrographic Surveys on the Labrador Shelf
复制标题
DOI：
10.1175/jcli-d-19-0083.1
复制
发表时间：
2020-10-15
影响因子：
4.9
通讯作者：
Holliday, N. Penny
中科院分区：
文献类型：
--
作者：
Florindo-Lopez, Cristian;Bacon, Sheldon;Holliday, N. Penny
虽然存在合理的知识，几十年的北极淡水储存的变化，我们对类似的时间尺度上的北极淡水出口知之甚少。水文时间序列从拉布拉多大陆架，跨越70年的年度分辨率，在这里用来量化北冰洋淡水出口格陵兰岛以西的变化。高分辨率冰-海耦合模型的输出用于确定这些水文剖面的代表性。出现了明显的年度到年代际变化，在20世纪50年代和70年代至80年代期间有高淡水输送，在60年代和90年代中期至2016年期间有低输送，典型振幅为30 mSv（1 Sv = 10（6）m（3）s（-1））。运输和累积量的变化与北极和北大西洋淡水储量在同一时间尺度上的变化密切相关。我们把拉布拉多海流的“近岸分支”称为拉布拉多沿岸海流，因为它是一个动力学和地理上独特的特征。它起源于哈德逊湾流出，并保留了从河流径流到哈德逊湾集水区的变化。我们发现需要从弗拉姆和戴维斯海峡平行，长期的淡水运输测量，以更好地了解北极淡水出口控制机制和格陵兰岛西部和东部路线之间的变异性分区，并需要更好地了解和理解拉布拉多大陆架全年（固体和液体）淡水通量。我们的研究结果对北冰洋和北大西洋北方的淡水通量和含量的更广泛，一致的大气控制具有影响。
While reasonable knowledge of multidecadal Arctic freshwater storage variability exists, we have little knowledge of Arctic freshwater exports on similar time scales. A hydrographic time series from the Labrador Shelf, spanning seven decades at annual resolution, is here used to quantify Arctic Ocean freshwater export variability west of Greenland. Output from a high-resolution coupled ice-ocean model is used to establish the representativeness of those hydrographic sections. Clear annual to decadal variability emerges, with high freshwater transports during the 1950s and 1970s-80s, and low transports in the 1960s and from the mid-1990s to 2016, with typical amplitudes of 30 mSv (1 Sv = 10(6) m(3) s(-1)). The variability in both the transports and cumulative volumes correlates well both with Arctic and North Atlantic freshwater storage changes on the same time scale. We refer to the "inshore branch" of the Labrador Current as the Labrador Coastal Current, because it is a dynamically and geographically distinct feature. It originates as the Hudson Bay outflow, and preserves variability from river runoff into the Hudson Bay catchment. We find a need for parallel, long-term freshwater transport measurements from Fram and Davis Straits to better understand Arctic freshwater export control mechanisms and partitioning of variability between routes west and east of Greenland, and a need for better knowledge and understanding of year-round (solid and liquid) freshwater fluxes on the Labrador shelf. Our results have implications for wider, coherent atmospheric control on freshwater fluxes and content across the Arctic Ocean and northern North Atlantic Ocean.