Characteristics and influencing factors of frontal upwelling in the Yellow Sea in summer

Frontal upwelling is an important phenomenon in summer in the Yellow Sea(YS)and plays an essential role in the distribution of nutrients and biological species.In this paper,a three-dimensional hydrodynamic model is applied to investigate the characteristics and influencing factors of frontal upwelling in the YS.The results show that the strength and distribution of frontal upwelling are largely dependent on the topography and bottom temperature fronts.The frontal upwelling in the YS is stronger and narrower near the eastern coast than near the western coast due to the steeper shelf slope.Moreover,external forcings,such as the meridional wind speed and air temperature in summer and the air temperature in the preceding winter and spring,have certain influences on the strength of frontal upwelling.An increase in air temperature in the previous winter and spring weakens the frontal upwelling in summer;in contrast,an increase in air temperature in summer strengthens the frontal upwelling.When the southerly wind in summer increases,the upwelling intensifies in the western YS and weakens in the eastern YS.The air temperature influences the strength of upwelling by changing the baroclinicity in the frontal region.Furthermore,the meridional wind speed in summer affects frontal upwelling via Ekman pumping.

Structure and formation of the South Yellow Sea water mass in the spring of 2007

Data obtained from over 250 CTD stations in December 2006 and April 2007 were used to analyze the temperature and salinity structure of the water masses of the South Yellow Sea in spring.Six basic water masses were identifi ed:the Southwest Yellow Sea Coastal Water Mass(SWYSCWM),Southwest Yellow Sea Local Water Mass(SWYSLWM),Qingdao Cold Water Mass(QDCWM),Yellow Sea Warm Current Water Mass(YSWCWM),Inchon Cold Water Mass(ICWM),and Subei Coastal Water Mass(SBCWM).The mechanisms of formation of these water masses are very diff erent.The SWYSCWM is aff ected by continental water,whereas the SWYSLWM and SBCWM are local water masses that are less aff ected by other waters.The QDCWM derives from cold northern water.The YSWCWM exists from winter to spring.Because of the limited data coverage,the mechanism of formation of the ICWM remains unclear.