Variability of sea ice melt and meteoric water input in the surface Labrador Current off Newfoundland
Variability of sea ice melt and meteoric water input in the surface Labrador Current off Newfoundland
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纽芬兰近海表面拉布拉多洋流海冰融化和大气水输入的变化
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Aicha Naamar
中科院分区：
文献类型：
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作者：
M. Benetti;G. Reverdin;C. Pierre;S. Khatiwala;B. Tournadre;S. Ólafsdóttir;Aicha Naamar
利用2012年至2015年期间在纽芬兰以东收集的盐度、δ 18 O和营养数据，对拉布拉多海流表面的盐水（大西洋和太平洋水）和淡水（海冰融化、大气降水）组分的各自贡献进行了量化，以研究与不同淡水贡献相关的盐度季节性变化。营养数据表明，2012-2015年，表层盐水平均由大约62%的大西洋水和38%的太平洋水组成。在中陆架存在一个大的盐度季节循环，其峰-峰幅度为1.5，这可以用淡水输入的季节变化来解释：2/3的盐度季节循环幅度可以由大气降水输入解释，1/3可以由海冰融化解释。一个较小的季节性盐度循环（1.3），观察到的内陆架相比，中间的货架，因为较小的变化，在大的大气降水输入。此外，数据显示，海冰融化（SIM）输入是特别重要的，在2014年7月，继2013/2014年冬季期间拉布拉多大陆架上的海冰更大的延伸，与前两个冬季相比。2014年7月和2015年4月期间观测到的一些SIM贡献较大的斑块位于大陆坡或更远的近海。2012-2015年数据与1994-1995年收集的数据的比较表明，纽芬兰大陆架和斜坡上的地表水在这两个时期都受到海冰过程的强烈影响，并表明1994-1995年期间斜坡上的盐水贡献更大。
The respective contributions of saline (Atlantic and Pacific water) and freshwater (sea ice melt, meteoric water) components in the surface Labrador Current are quantified using salinity, δ18O, and nutrient data collected between 2012 and 2015 east of Newfoundland to investigate the seasonal variability of salinity in relation with the different freshwater contributions. Nutrient data indicate that the surface saline water is composed on average over 2012–2015 of roughly 62% Atlantic Water and 38% Pacific Water. A large salinity seasonal cycle of ≈ 1.5 peak-to-peak amplitude is found over the middle continental shelf, which is explained by the freshwater input seasonal variability: 2/3 of the amplitude of the salinity seasonal cycle can be explained by meteoric water input and 1/3 by the sea ice melt. A smaller seasonal salinity cycle (≈1.3) is observed over the inner shelf compared to the middle shelf, because of smaller variability in the large meteoric water inputs. Furthermore, the data reveal that sea ice melt (SIM) input was particularly important during July 2014, following a larger extension of sea ice over the Labrador shelf during the 2013/2014 winter season, compared to both previous winter seasons. Some patches of large SIM contribution observed during July 2014 and April 2015 were located on the continental slope or further offshore. The comparison of 2012–2015 data with data collected in 1994–1995 shows that the surface water over the Newfoundland shelf and slope is strongly affected by sea ice processes in both periods and suggests a larger contribution of brines over the slope during 1994–1995.