Application Of Underwater Glider To The Study Of Mixed Layers And Eddies In The Northwest Pacific Ocean

After the quality control of salinity data obtained by underwater gliders(including the removal of anomalous undulating profiles and surface "circles" and the correction of thermal lag of salinity),the variation of the mixed layer in the Northwest Pacific Ocean was studied based on the underwater glider data and satellite remote sensing data.The results show that the temperature in the mixing layer generally decreases with the seasonal transition(from the end of August to the end of October),and the thickness of the mixing layer generally increases with the seasonal transition.According to the phenomenon of abnormal temperature decrease in the ocean mixture layer observed by underwater gliders,combined with the satellite remote sensing data,it is found that the phenomenon is caused by an eddy,the vertical coiling effect of the eddy leads to the upwelling of the deep sea water,so that the temperature in the ocean mixture layer decreases and the thickness of the mixture layer decreases.Then,multi-source satellite remote sensing data are used to identify and track the life process of the cold eddy.The results show that the cold eddy was generated on September 8,2019,and died on March 4,2020.The eddy mainly moved to the southwest.In the evolution process of the life cycle of the cold eddy,the shape of the cold eddy is constantly stretched.The energy density of the eddy EI is approximately negatively correlated with the radius of the cold eddy during its life cycle,and the deformation trend of the cold eddy makes it unable to maintain a perfectly circular shape.The cold eddy is stable in its life cycle with only a small amount of energy loss during its propagation.The resultant cold eddy presents an obvious negative temperature anomaly in the vertical direction and has a "dual core structure",while the salinity anomaly presents a "negative upper and positive lower" characteristic in the vertical direction.Finally,satellite remote sensing data are used to statistically analyze the eddies in two areas of the Northwest Pacific Ocean(A: 120-180°E,20-30°N,B: 142-180°E,30-40°N),including their basic characteristics,spatial distribution and propagation characteristics,and the seasonal and inter-annual variation rules are analyzed.By comparison,it is found that the characteristics of eddies in the two sea areas are quite different.Combined with Argo(Array for Real-time G-Costrophic Oceanography)data and shipborne CTD(Conductivity Temperature and Depth)data,the vertical structure characteristics of eddies in the sea area(A and B)were studied.The results show that the anomaly of geopotential temperature and salinity in the whole synthetic section of the eddies in A area are smaller than that in B area,which is opposite to the anomaly of geopotential density.