Based on the high-resolution oceanic numerical model product of MITgcm with a resolution of(1/48)°,the geostrophic balanced motion and unbalanced wave motion are decomposed via the frequency-wavenumber spec-trum analysis method to analyze the distribution of submesoscale characteristics and diagnose the main factors af-fecting their seasonal variations in the Agulhas current system.The results show that the submesoscale processes in the Agulhas current system have a significant seasonal distribution with strong features in winter but weak features in summer.The mixed layer baroclinic instability is the main reason affecting the submesoscale seasonal differ-ences in the area.In addition,the geostrophic balanced motions are predominant in the submesoscale process in the regions with stronger eddy kinetic energy(EKE)and have no obvious seasonality.For the regions with weaker EKE,the balanced and unbalanced geostrophic motions show significant seasonality,where the local mixing layer shallowness is responsible for the increase of the unbalanced kinetic energy in summer.Our analysis helps to fur-ther clarify the characteristics of submesoscale seasonal variation and its primary factors in the Agulhas current sys-tem.The effective separation of geostrophic balanced and unbalanced motion enhances our understanding of en-ergy transformation between multiscale processes in the ocean.
关键词
阿古拉斯流域/亚中尺度过程/地转平衡运动/非地转运动/过渡尺度
Key words
Agulhas current system/submesoscale process/geostrophic balanced motion/unbalanced wave motion/trans-ition scale
维普
万方数据