近几十年来，受气候变化影响，格陵兰海深层对流显著减弱，北欧海溢流水变淡，而溢流强度并未如模式模拟那样发生显著减弱。目前对北欧海溢流强度的分析多是基于数值模拟结果，无法完全反映真实的海洋情况。北欧海溢流为水压控制，其流量取决于格陵兰-苏格兰海脊两侧的在溢流核心深度上的压强差，为海平面主导的正压压强差和温盐结构导致的斜压压强差的和。本项目将基于卫星高度数据和实测温盐数据，从上游溢流水存量和动力驱动两个方面分析溢流强度稳定的原因。阐述对流、混合增密等高密度水生成过程对北欧海内溢流水存量变化的影响；揭示北欧海海平面和温盐结构的变化特征和主要影响因素；利用模式诊断分析外部过程通过正压和斜压效应对溢流强度的影响。本项目将有助于加深对维持北欧海溢流强度稳定的主要物理过程的认识，提高溢流模拟预测的准确性，增进对极区海洋过程在全球气候系统中地位的理解。

In recent decades, Nordic sea overflow freshen as consequence of the climate change and decrease of deep convection in Greenland sea. However, the overflow intensity is not significantly weakened as the model simulation. Now, research on the overflow intensity mostly bases on model results, which could not completely reflect the facts of real ocean. Nordic sea overflow is hydraulic control, its flux depends on pressure difference between both sides of the Greenland–Scotland Ridge at the depth of the overflow core. The pressure diiference is the sum of a barotropic component determined by the sea level and a baroclinic component given by the density field. In this study, based on altimeter data and observant temperature and salinity data, analyze the reason of stability of overflow flux from storage of overflow waters in upstream and dynamic derivation. Some work are revealed to find out the effects of dense waters production, such as convection and cabbeling, to change of overflow waters volume in Nordic sea. The effects of external drive to overflow flux through barotropic and baroclinic way is analyzed by numerical model. This study will help to increase the knowledge of the main phiscal process, which maintain the overflow flux, and also can contribute to improvement of modeling prediction on overflow. In the context of the Arctic warming amplification, this study can contribute to recognize the important role of polar ocean processes in global climate system.