Statistical Analysis Of Ocean Fronts And Eddies Of Japan Sea

Japan Sea is an important passage through the Arctic Ocean in China.It is of great scientific significance and practical significance to study the ocean front and eddy in the Sea of Japan.Based on SODA data from 1993 to 2015,this paper extracted ocean front information using the absolute gradient method,analyzed the spatial distribution characteristics of Japan sea front area,the position of front axis,the frequency of front occurrence and the depth of frontal influence,and studied the spatial distribution and seasonal variation characteristics of temperature front and salinity front of Japan sea.The results show that the temperature front has a trend of southwest to northeast on the whole,with significant seasonal variation characteristics,and the summer front is obviously stronger than the winter front.The axis of the front did not fluctuate significantly with the seasons,but moved towards the coast of Japan with the increase of depth.The salinity front is not as obvious as the temperature front and its distribution area is relatively small.The seasonal variation of the salinity front is obvious,the winter front is stronger than the summer front,and the position of the front axis is relatively stable and almost does not oscillate.The salinity front can be divided into two parts: the Tsushima Strait front and the northern Japan Sea front.The Tsushima Strait front is located near the Tsushima Strait and has the same characteristics as the local temperature front.The northern front of the Sea of Japan is located in the northernmost part of the Sea of Japan,along the Russian coast.At the same time,the correlation between temperature front and salinity front and wind stress curl and Japan current system is discussed.The results show that the temperature front strength is significantly positively correlated with wind stress curl in winter,while the salinity front strength is significantly positively correlated with wind stress curl in spring.Both the temperature front and the salinity front reflect the structural characteristics of the Japanese current system,and the frontal distribution area is located in the region or the edge of the Japanese current system.Based on the satellite altimeter data from 1993 to 2015,the mesoscale eddies in the Sea of Japan have been detected,identified and tracked by geometric methods.The consensus is that 188 anti-air eddies and 73 air eddies are identified.At the same time,the seasonal and annual distribution characteristics of mesoscale eddies were analyzed.It was found that the number of mesoscale eddies was the highest in autumn,and the lowest in winter.There are three significant abnormal years for the generation of eddies,the abnormal maximum in 2014,and the abnormal minimum in 1995 and 2001.The eddies are mainly generated and disappeared along the coast of the Korean Peninsula and the sea to the east of the Jonggu Strait.The annual variation of sea surface temperature(SST)and wind stress curl has a significant negative correlation with the number of eddies,which indicates that the generation of eddies is affected by sea surface temperature(SST)and wind stress curl,and SST can change the stratification strength of the upper ocean and then affect the generation of eddies.