Mesoscale eddies are an important component of oceanic features.How to automatically identify these mesoscale eddies from available data has become an important research topic.Through careful examination of existing m...Mesoscale eddies are an important component of oceanic features.How to automatically identify these mesoscale eddies from available data has become an important research topic.Through careful examination of existing methods,we propose an improved,SSH-based automatic identification method.Using the inclusion relation of enclosed SSH contours,the mesoscale eddy boundary and core(s) can be automatically identified.The time evolution of eddies can be examined by a threshold search algorithm and a tracking algorithm based on similarity.Sea-surface height(SSH) data from Naval Research Laboratory Layered Ocean Model(NLOM) and sea-level anomaly(SLA) data from altimeter are used in the many experiments,in which different automatic identification methods are compared.Our results indicate that the improved method is able to extract the mesoscale eddy boundary more precisely,retaining the multiple-core structure.In combination with the tracking algorithm,this method can capture complete mesoscale eddy processes.It can thus provide reliable information for further study of reconstructing eddy dynamics,merging,splitting,and evolution of a multi-core structure.展开更多
亚中尺度过程是海洋学研究的前沿热点领域,从高分辨率资料中实现亚中尺度信号的快速提取对开展亚中尺度动力学研究具有重要意义。为此,根据亚中尺度过程的物理特性,提出一种基于深度学习的自动识别方法,构建了基于U-Net网络的海洋亚中...亚中尺度过程是海洋学研究的前沿热点领域,从高分辨率资料中实现亚中尺度信号的快速提取对开展亚中尺度动力学研究具有重要意义。为此,根据亚中尺度过程的物理特性,提出一种基于深度学习的自动识别方法,构建了基于U-Net网络的海洋亚中尺度过程识别网络(submesoscale processes automatic identification network, SM-Net),该网络采用视觉几何组网络作为主干特征提取网络并引入改进的混合注意力模块以提升识别能力。基于高分辨率MITgcm (Massachusetts Institute of Technology general circulation model)模式数据,通过SM-Net准确识别出南海东北部全年的亚中尺度过程,并分类为冷涡、暖涡和锋面。南海东北部亚中尺度冷涡、暖涡和锋面均多发生于冬季,夏季的发生频率较低,但吕宋海峡的亚中尺度过程全年均较为活跃。除吕宋海峡外,亚中尺度冷涡夏季多发生于台湾岛西南海域、吕宋岛西南海域和吕宋岛沿岸,冬季多发生于南海北部陆坡陆架区;亚中尺度暖涡夏季多发生于吕宋岛沿岸,冬季在南海北部陆坡陆架区较为活跃;亚中尺度锋面的时空特征与冷涡相似,但黑潮流经区域的发生频率更高。亚中尺度过程罗斯贝数和动能的时空特征与发生频率具有较好的一致性,暖涡的动能、罗斯贝数和直径均弱于冷涡。上述识别方法在南海的成功运用,为应用SWOT (surface water and ocean topography)卫星数据研究亚中尺度过程提供了一定参考。展开更多
基金jointly supported by a grant from the National Natural Science Foundation of China(General Program)(41071250)Innovation Program of State Key Laboratory of Resources and Environmental Information System,Institute of Geographic SciencesNatural Resources Research,Chinese Academy of Sciences(088RA500KA)
文摘Mesoscale eddies are an important component of oceanic features.How to automatically identify these mesoscale eddies from available data has become an important research topic.Through careful examination of existing methods,we propose an improved,SSH-based automatic identification method.Using the inclusion relation of enclosed SSH contours,the mesoscale eddy boundary and core(s) can be automatically identified.The time evolution of eddies can be examined by a threshold search algorithm and a tracking algorithm based on similarity.Sea-surface height(SSH) data from Naval Research Laboratory Layered Ocean Model(NLOM) and sea-level anomaly(SLA) data from altimeter are used in the many experiments,in which different automatic identification methods are compared.Our results indicate that the improved method is able to extract the mesoscale eddy boundary more precisely,retaining the multiple-core structure.In combination with the tracking algorithm,this method can capture complete mesoscale eddy processes.It can thus provide reliable information for further study of reconstructing eddy dynamics,merging,splitting,and evolution of a multi-core structure.
文摘亚中尺度过程是海洋学研究的前沿热点领域,从高分辨率资料中实现亚中尺度信号的快速提取对开展亚中尺度动力学研究具有重要意义。为此,根据亚中尺度过程的物理特性,提出一种基于深度学习的自动识别方法,构建了基于U-Net网络的海洋亚中尺度过程识别网络(submesoscale processes automatic identification network, SM-Net),该网络采用视觉几何组网络作为主干特征提取网络并引入改进的混合注意力模块以提升识别能力。基于高分辨率MITgcm (Massachusetts Institute of Technology general circulation model)模式数据,通过SM-Net准确识别出南海东北部全年的亚中尺度过程,并分类为冷涡、暖涡和锋面。南海东北部亚中尺度冷涡、暖涡和锋面均多发生于冬季,夏季的发生频率较低,但吕宋海峡的亚中尺度过程全年均较为活跃。除吕宋海峡外,亚中尺度冷涡夏季多发生于台湾岛西南海域、吕宋岛西南海域和吕宋岛沿岸,冬季多发生于南海北部陆坡陆架区;亚中尺度暖涡夏季多发生于吕宋岛沿岸,冬季在南海北部陆坡陆架区较为活跃;亚中尺度锋面的时空特征与冷涡相似,但黑潮流经区域的发生频率更高。亚中尺度过程罗斯贝数和动能的时空特征与发生频率具有较好的一致性,暖涡的动能、罗斯贝数和直径均弱于冷涡。上述识别方法在南海的成功运用,为应用SWOT (surface water and ocean topography)卫星数据研究亚中尺度过程提供了一定参考。
