Variations in ocean currents, sea ice concentration, and sea surface temperature along the North-East coast of Greenland (NEG-OCEAN)

根据遥感数据确定格陵兰东北海岸海面洋流的时间演变，并结合海冰浓度和海面温度进行分析，为研究冰盖、海洋和海冰之间的耦合机制（连同两个捆绑项目）提供依据。在过去的几十年里，格陵兰冰原经历了冰原质量损失的急剧增加，这既是由于表面融化的加剧，也是由于出口冰川的加速和冰出口速率的提高。与前几十年相比，格陵兰冰盖对全球海平面上升的贡献在过去二十年中翻了一番。融水改变了冰盖的热结构，影响了基底边界条件。此外，冰舌与海水之间的相互作用对出海口冰川的动力学有直接影响。温暖的峡湾海水影响冰下融化，增加冰通量。相反，流入沿海海的淡水通量的增加只影响沿海岸的水和能量<e:1>输送。因此，研究冰盖、其海洋出口冰川和依赖于大气强迫的海洋环流之间的反馈机制，是理解这一复杂系统在全球范围内的变异性及其影响的极其重要的一步。目前项目的重点是海洋部分。结合最新的重力场模型，对卫星高度计数据进行了专门的处理，估计出了一个可以转化为地转速度场的海洋动态地形时间序列。地形、海冰浓度和海面温度的主成分分析应找出最主要的模式，为研究冰盖质量损失的相关性和研究冰盖、海洋和海冰之间的耦合机制提供依据。

Based on remote sensing data the temporal evolution of ocean surface currents at the North Eastcoast of Greenland shall be determined and - together with sea ice concentration and sea surfacetemperature - analyzed in order to provide a basis for studying (together with two bundled projects)the coupling mechanism between ice sheet, ocean, and sea ice.During the last decades the Greenland ice sheets experienced a strongly increased mass loss of icesheets, both due to enhanced surface melting and due to the acceleration of outlet glaciers andhigher ice export rates. Compared to the earlier decades, the conuibution of the Greenland ice sheetto global sea level rise doubled during the last two decades. Melt water changes the thermalstmcture of the ice sheet and influences the basal boundary conditions. In addition, interactionsbetween the glacier tongues and the ocean water have a direct impact on the dynamics of outletglaciers. Warm fjord waters impact subglacial melting and increase the ice flux. Conversely, theincrease of fresh water flux into the coastal sea su^ongly influences the water and energy ü-ansportalong the coast. The investigation of the feedback mechanisms between the ice sheet, its marinebased outlet glaciers and the ocean circulation in dependence of atmospheric forcing is therefore anextremely important step in understanding the variability of this complex system and itsimplications on a global scale. The present project focuses on the ocean component. A dedicatedprocessing of satellite altimeter data combined with the most recent gravity field models is used toestimate a time series of the dynamic ocean topography which can be transformed into ageostrophic velocity field. Principal component analyses of topography, sea ice concentration andsea surface temperature shall identify the most dominant modes, in order to provide a basis forinvestigating correlation with mass loss of ice sheets and studying the coupling mechanism betweenice sheet, ocean and sea ice.