2013年夏季琼东海域上升流观测研究

Coastal upwelling off eastern Hainan Island observed in the summer of 2013

利用2013 年夏季国家自然科学基金委员会南海西部航次获得的观测资料, 并结合卫星遥感海面温度和风场资料,对琼东海域夏季上升流的空间结构及其演变过程进行了分析.研究结果表明, 在2013 年夏季航次观测期间, 琼东海域存在显著的上升流现象, 但表层上升流信号较弱, 强上升流主要发生在30-50m 的下层海域, 上升流中心海域与外围海水在下层的温度差超过7℃, 盐度差可达到0.7‰以上.进一步分析航次期间的一次热带气旋过程对琼东上升流的影响,结果表明热带气旋破坏了上升流的上层结构, 且琼东上升流对风场变异的响应过程存在2-4d 的滞后.

Based on in-situ observations supported by the National Natural Science Foundation of China during the summer of 2013 as well as satellite data, the summer coastal upwelling off eastern Hainan Island is examined in details, including its spatial structure, evolution process and the response to a tropical cyclone during the cruise. The results suggest that the upwelling anchored off eastern Hainan Island, with relatively weak signals at the sea surface. The observed strong upwelling mainly took place between the depths of 30-50 m below the surface. The temperature difference between the cooling center and the offshore non-upwelling water was more than 7°C, and the salinity difference was more than 0.7 psu. Moreover, the analysis of a tropical cyclone onset indicates that the structure of coastal upwelling in the upper ocean was completely destroyed, due to the shutdown of upwelling-favorable winds and intensive mixing induced by the tropical cyclone. Throughout these processes, the coastal upwelling lagged behind alongshore wind by 2-4 days.