Variation of the fresh water in the western Nordic Seas

北欧西部海域淡水的变化

• 批准号: 225915117
• 负责人: Professorin Dr. Ursula Schauer
• 金额: --
• 依托单位: Alfred-Wegener-Institut (AWI) Helmholtz-Zentrum für Polar- und Meeresforschung
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/225915117?language=en
• 关键词: Variation; fresh; water; western; Nordic

The goal of this project is to capture and analyse the freshwater fluctuations in the western Nordic Seas, to identify their sources and to understand the underlying mechanisms. The Nordic Seas are shaped by the strong salinity contrast arising from the northward flow of saline Atlantic Water along their eastern rim and the southward flow of very fresh Polar Water along their western rim in the East Greenland Current (EGC). The huge import of freshwater to the Arctic Ocean from continental runoff and from the Pacific Ocean, and the freshwater accumulated at the surface through sea ice formation is drained to the North Atlantic. Part of it is carried in the EGC as sea ice and in liquid form. In the Nordic Seas freshwater is added to the EGC by an increasing rate of runoff from Greenland. A fraction of this freshwater drains from the EGC via branching and through mesoscale features into the central Nordic Seas. The amount and the vertical distribution of this freshwater influence the density stratification in the Nordic Seas and thus the convection depth and the formation of deep waters. The last decades showed significant changes of the freshwater yield and distribution in the Nordic Seas and of the convective activity. Recent studies, also those of the first phase of FOR1740, indicate that mostly sea ice is the source of freshwater for the inner Nordic Seas. In this project we will investigate the structure of the freshwater leakage from the EGC to the inner western Nordic Seas by long-term (months to seasons) glider missions, and analyse the underlying processes and their variability. We will analyse this leakage in the context of freshwater changes in the inner basins derived from Argo floats and use input from TP2.1 for assessing the contribution of net precipitation as compared to the leakage from the EGC.

该项目的目标是捕捉和分析北欧西部海域的淡水波动，查明其来源并了解其根本机制。北欧海的形成是由于沿其东部边缘的咸水大西洋水向北流动，以及沿其西部边缘的极淡水在东格陵兰洋流(EGC)中向南流动所产生的强烈的盐度对比。从大陆径流和太平洋向北冰洋输入的大量淡水，以及通过海冰形成在表面积累的淡水被排到北大西洋。其中一部分以海冰和液体的形式在EGC中携带。在北欧海域，淡水随着格陵兰岛径流的增加而增加到EGC中。其中一小部分淡水通过分支和中尺度特征从EGC排出，进入北欧中部海域。这些淡水的数量和垂直分布影响北欧海域的密度分层，从而影响对流深度和深水的形成。近几十年来，北欧海域的淡水产量和分布以及对流活动都发生了显著变化。最近的研究，以及FOR1740第一阶段的研究表明，大部分海冰是北欧内海的淡水来源。在这个项目中，我们将通过长期(从月到季)的滑翔机任务，调查从EGC到北欧内海的淡水泄漏的结构，并分析潜在的过程及其变异性。我们将在ARGO浮标产生的内盆地淡水变化的背景下分析这种泄漏，并使用TP2.1的投入来评估净降雨量相对于EGC泄漏的贡献。