Temporal and spatial variation of the mesoscale cold coreeddy in the East China Sea

摘要

The East China Sea is important not only as a good fishing ground but also nursery and spawning arearnfor many kinds of fishes. The East China Sea is characterized by three distinct water masses from NOAA satelliternremote sensing. Those are the Kuroshio and a branch (the Tsushima Warm Current), which flows along the easternrnboundary of the seas, a cold water mass originating from the northern Yellow Sea and the northern Chinese coasts,rnand a warm monsoon current form the South China Sea.rnDuring the winter, cold air moves from Asiatic continent over the East China Sea, the overall cooling of surfacernwater and the following convection allows an equalization of the temperature of sea water from the surface to bottom.rnHowever, when the winds blow from the southeast at an intensity comparable to that in the winter period, a warmrnmonsoon current which originates form the South China Sea flows into the East China. As a result of the warm Kuroshiornand Tsushima Currents which are also stronger when the winds blow from southeast, temperatures are considerablyrnhigher around the extended cold water from the coast of the East China.rnAt that time, the cold water was captured by warm water from the Kuroshio and Tsushima currents. Therefore,rnmesoscale cold core eddies formed in diameter of 150km had occurred in the East China Sea in May, 1999 and February,rn2003.rnThe mechanism of eddy formation was studied by each condition, including boundary condition between the EastrnChina coastal cold water and the Kuroshio warm current, wind data related to the monsoon which was measuredrnQuikSCAT, and the bottom topography of the East China Sea.