Salinity changes in the World Ocean since 1950 in relation to changing surface freshwater fluxes
Salinity changes in the World Ocean since 1950 in relation to changing surface freshwater fluxes
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DOI：
10.1007/s00382-014-2131-7
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发表时间：
2014-08-01
期刊：
影响因子：
4.6
通讯作者：
Allan, Richard P.
中科院分区：
文献类型：
--
作者：
Skliris, Nikolaos;Marsh, Robert;Allan, Richard P.
全球水文和海气淡水通量数据集被用来研究1950-2010年海洋盐度变化与地表淡水通量的关系。在年代际尺度上，以蒸发（降水）为主的区域表层盐度增加（减少），南极-太平洋盐度反差增大，温跃层上层盐度最大值增大，中层沃茨盐度最小值减小。在E-P的潜在趋势进行了检查，1950-2010年（使用两个再分析）和1979-2010年（使用四个再分析和两个混合产品）。1950-2010年E-P趋势模式的巨大差异在几个区域，特别是北大西洋明显。对于1979-2010年的空间变化模式的一些一致性是明显的，但仍然有一个大的传播趋势的大小和符号之间的六个E-P产品。然而，在南半球副热带环流的E-P增加的一个强大的模式被认为是在所有的产品。在热带太平洋也有一些证据表明，与ENSO有关的盐度和E-P的空间变化模式之间存在联系。随后推断在特定区域的水循环放大率从所观察到的3-D盐度变化场使用盐守恒方程在可变等密度体积，隐式占等密度表面的迁移。1950-2010年全球E-P的变化表明，整个副热带地区的净蒸发量增加了1 +/-A0.6%，整个副极地地区的净降水量增加了4.2 +/-A2%。在1979-2010年期间，放大率大约翻了一番，这与加速的大规模变暖相一致，但也与后一时期盐度采样的大幅改善相一致。
Global hydrographic and air-sea freshwater flux datasets are used to investigate ocean salinity changes over 1950-2010 in relation to surface freshwater flux. On multi-decadal timescales, surface salinity increases (decreases) in evaporation (precipitation) dominated regions, the Atlantic-Pacific salinity contrast increases, and the upper thermocline salinity maximum increases while the salinity minimum of intermediate waters decreases. Potential trends in E-P are examined for 1950-2010 (using two reanalyses) and 1979-2010 (using four reanalyses and two blended products). Large differences in the 1950-2010 E-P trend patterns are evident in several regions, particularly the North Atlantic. For 1979-2010 some coherency in the spatial change patterns is evident but there is still a large spread in trend magnitude and sign between the six E-P products. However, a robust pattern of increased E-P in the southern hemisphere subtropical gyres is seen in all products. There is also some evidence in the tropical Pacific for a link between the spatial change patterns of salinity and E-P associated with ENSO. The water cycle amplification rate over specific regions is subsequently inferred from the observed 3-D salinity change field using a salt conservation equation in variable isopycnal volumes, implicitly accounting for the migration of isopycnal surfaces. Inferred global changes of E-P over 1950-2010 amount to an increase of 1 +/- A 0.6 % in net evaporation across the subtropics and an increase of 4.2 +/- A 2 % in net precipitation across subpolar latitudes. Amplification rates are approximately doubled over 1979-2010, consistent with accelerated broad-scale warming but also coincident with much improved salinity sampling over the latter period.