The Detection Of Mesoscale Eddies In The East Of Taiwan And Its Impact On The Path Of Kuroshio Intrusion To The East China Sea

The mesoscale eddy contains huge kinetic energy which is almost more than about 80% of the whole kinetic energy of the ocean circulation at the same time, and it will transfer energy as well as transfer mass. The mesoscale eddy will influence the distribution of elements, such as temperature, salinity and chlorophyll. Meanwhile mesoscale eddies at the east of Taiwan in the northwest Pacific Ocean are quite active. Some of the mesoscale eddies which originate from the deep ocean will spread to the west and then enter into the range of Kuroshio mainstream, thereby affect it. Kuroshio which is carrying the high temperature and high salinity water of low latitudes transmit the matter and energy of the Pacific, invade the East China Sea shelf in the northeast of Taiwan, and influence the East China Sea circulation system and ecosystem further. In this paper 21 years AVISO satellite altimeter data in used, and the area 120 ° E- 130 ° E, 17 ° N- 27 ° N is selected as the study area. The mesoscale vortex automatic detection algorithm is used to detect and track mesoscale eddies in the east of Taiwan. Study the effect of mesoscale eddies on the path of the Kuroshio intrusion in the East China Sea. The following conclusions are obtained.1. Through several groups of sensitivity tests, the parameters are ultimately determined that a = 2 and b = 1. In this case the vortex automatic detection algorithm is able to more accurately identify and track the mesoscale vortex.2. In the study area the number of eddies have obvious seasonal variation characteristics. The number of eddies in spring is larger than any other season, and the number of vortex in each mouth is more than 115. In February, July and September there are a little bit more eddies which is between 105 to 114, meanwhile the number of eddies in December(79) is the least. In the study area the number of cyclonic eddies is smaller than anticyclonic eddies in the spring and summer and larger in autumn and winter.3. Different type of eddies, single vortex or multiple vortexes have big difference of impact on the path of Kuroshio and intrusion to the shelf. With the examples in 2003, find out that when the anticyclonic eddies are transported to the scope of Kuroshio, the path of Kuroshio will weaken and its velocity of will increase. Meanwhile when the cyclonic eddies are transported to the scope of Kuroshio, the Kuroshio intrusion will enhance and the velocity of Kuroshio will decrease. In 2008 when large scale range of mesoscale vortex appeared in the scope of Kuroshio mainstream, northeast of Taiwan Kuroshio turn around about 30° anticlockwise, makes the Kuroshio directly onto the East China Sea shelf. Particularly there are multiple vortexes existing in the area of east of Taiwan in the summer of 2004. At the same time Kuroshio spindle in Luzon strait had an evident movement to east and invasion path of Kuroshio to the east China changed dramatically.