Study On Subsurface Eddy In South China Sea Based On Observation Data

With the rapid development of satellite remote sensing data,more and more mesoscale eddies in the South China Sea are studied using remote sensing data.By studying the spatial and temporal distribution characteristics of mesoscale eddies in the South China Sea,it is found that the mesoscale eddies in the South China Sea are particularly active and seasonally influenced.However,the observed eddies are mainly surface eddies restricted by data.In this paper,the temporal and spatial distribution and seasonal variation characteristics of subsurface eddies are studied by fusing the observed subsurface vortices,and are verified by reanalysis data.The relationship between sea surface height anomaly and the depth of thermocline is also studied to improve the error of thermocline.The main achievements of the paper include the following aspects.First,the three-dimensional temperature field in the South China Sea was reconstructed by using the DIVA system based on the fusion of Argo and GTSPP data from 2000 to 2017.The sub-surface warm eddy near the coast of Vietnam was taken as the research object to study its spatial and temporal distribution.Secondly,a section composed of partial drifting trajectory is selected using four Argo buoys near the coast of Vietnam.According to the distribution of temperature anomaly section,a warm eddy is found in the subsurface near the coast of Vietnam.Two reanalysis data CARS and GDEM were used to study surface and subsurface eddies near the coast of Vietnam according to seasonal variation.The results show that the temporal and spatial distribution of subsurface eddies is similar to that of Agro-GTSPP data.Thirdly,based on the relationship between the sea surface height anomaly and the thermocline depth,the thermocline depth is calculated according to the high resolution sea surface height anomaly.The results show that there is a good correlation between them.