Deep water distribution and transport in the Nordic seas from climatological hydrological data
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摘要: 北欧海深层水是大西洋深层水的主要来源,它的产生和输运活动对于北极与北大西洋之间的热量和物质交换过程有着十分重要的作用。本文利用气候态水文数据集Hydrobase Ⅱ,对北欧海深层水的分布及其随深层环流运移的情况进行了估算。在根据水文数据计算深层流场的过程中,本文应用了一种新的改进P矢量法,通过引入海表面高度梯度来解决在没有无运动面的海域,传统P矢量法因无法完全消除正压流场残量而不能准确计算绝对地转流的问题。通过水团分析给出了北欧海各主要水团的水体数量、空间分布和季节变化特征,并与前人基于其他水文数据集给出的结果进行了对比。在环流和水团分布的分析基础上,进一步研究了深层水的时空变化与输运,估算出在格陵兰海盆内的深层水存在约为22×103km3的体积季节变化,而在罗弗敦海盆和挪威海盆则要小很多。在格陵兰-罗弗敦海盆和罗弗敦-挪威海盆之间的平均输运量分别约为1.54×103和0.64×103km3/a。海盆间深层水的输运基本是沿着格陵兰-罗弗敦-挪威海盆的方向进行的。
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关键词:
- 北欧海 /
- 深层水 /
- 改进P矢量法:HydrobaseⅡ
Abstract: Deep water in the Nordic seas is the major source of Atlantic deep water and its formation and transport play an important role in the heat and mass exchange between polar and the North Atlantic. A monthly hydrological climatology—Hydrobase II—is used to estimate the deep ocean circulation pattern and the deep water distribution in the Nordic seas. An improved P-vector method is applied in the geostrophic current calculation which introduces sea surface height gradient to solve the issue that a residual barotropic flow cannot be recognized by traditional method in regions where motionless level does not exist. The volume proportions, spatial distributions and seasonal variations of major water masses are examined and a comparison with other hydrological dataset is carried out. The variations and transports of deep water are investigated based on estimated circulation and water mass distributions. The seasonal variation of deep water volume in the Greenland Basin is around 22×103 km3 whereas significantly weaker in the Lofoten and Norwegian Basins. Annual downstream transports of about 1.54×103 and 0.64×103 km3 are reported between the Greenland/Lofoten and Lofoten/Norwegian Basins. The deep water transport among major basins is generally in the Greenland-Lofoten-Norwegian direction.-
Key words:
- the Nordic seas /
- deep water /
- modified P-vector method
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