The Transformation from Yellow Sea Warm Current Mode to Yellow Sea Cold Water Mode in Southern Yellow Sea in spring

The Southern Yellow Sea Cold Water Mass (SYSCWM) and Yellow Sea Warm Current (YSWC) are the typical phenomena in southern yellow sea in summer and winter. SYSCWM and YSWC appear at the same place in different seasons. The transformation from YSWC mode to SYSCWM mode in spring is analyzed by the in site observations. The result show that YSWC can exist at the bottom west of yellow sea central trough to later June while the traditional viewpoint think YSWC can only survive to April. Although SYSCWM formed from April and reach its strongest phase in august, the low temperature core of SYSCWM and the core of YSWC are not coincided. They constitute a sandwich like structure in the central southern yellow sea. Even in the strongest phase of SYSCWM, there are also exist high saline YSWC residual water while there are no clear northward current.