湾流及其邻近海域中尺度涡统计特征分析

为了得到中尺度涡的特征,综合利用1993-2012年共20a的卫星高度计资料及Argo浮标资料等,对湾流及其邻近海域的中尺度涡特征进行统计,并采用合成方法对涡的三维结构特征进行分析。结果表明:该海域气旋涡(CE)和反气旋涡(AE)的平均生命史及平均半径十分相近;湾流主体段与延续段的涡动能(EKE)、涡能量密度(EI)和涡度明显大于其他区域,气旋涡平均强度大于反气旋涡;对于生命周期内的长周期涡,半径和EKE的变化幅度较大,EI和涡度的变化较小;涡以西向移动为主,平均移速3.2cm/s;长周期气旋涡和反气旋涡均具有向赤道移动的特征;在垂直剖面上,气旋涡(反气旋涡)存在2个温度负(正)异常结构和上下2个盐度负(正)异常结构,涡对海水温盐的垂向影响可达1km以上。

Statistical characteristics of mesoscale eddies in the Gulf Stream and its adjacent sea

To obtain the characteristics of mesoscale eddies,the statistical characteristics of mesoscale eddies in the Gulf Stream and its adjacent sea were analyzed using satellite altimetry data of 20 years (1993-2012) as well as Argo profile data. Three-dimensional structure of the eddies were further analyzed with a kind of composite method. It is revealed that the average lifetime and radius of the cyclonic eddies (CE) and anticyclonic eddies (AE) are similar; that eddy kinetic energy (EKE), eddy intensity (EI) and vorticity of the eddies in the continuous segment and main section of the Gulf Stream are significantly higher than in other regions, and that the strength of cyclonic eddies is greater than anti-cyclonic eddies; that the radius and EKE of long-lived eddies present considerable variations during the lifespans, while the variations of EI and vorticity do not; that most eddies tend to propagate westward, with an average speed of 3.2 cm/s, and besides, both long-lived CEs and, AEs have equatorward deflection; and that CEs (AEs) have two negative (positive) temperature anomaly structure and two negative (positive) salinity anomaly structures in the vertical sections. The influence on water temperature and salinity by eddies can reach greater than 1000 m.