珠江伶仃河口湾及邻近内陆架的纵向环流与物质输运分析

ANALYSIS ON LONGITUDINAL NET CIRCULATIONS AND MATERIAL FLUXES IN LINGDING ESTUARY,PEARL RIVER AND ADJACENT INNER SHELF WATERS

根据实测资料分析了珠江伶仃河口湾与邻近内陆架在不同径流影响下的水体混合空间状态和季节变化特征。主要由河口湾表、中层冲淡水和内陆架底层上溯的高盐补偿流构成了河口湾和内陆架之间的净环流,在高径流量和西南大风的情况下,环流下移向内陆架扩展增强。计算表明,7月纵断面上的净环流输运是盐分纵向净通量的控制因素,输运方向指向上游,而其余季节则以向海的净平流输运为主。悬沙净通量主要受净平流及潮抽吸输运控制,潮抽吸输运强度与大小潮有较密切关系。

Based on measured data, this paper analyzed the fluids mixing spatial states and the season variabilities of longitudinal section under the conditions of different discharges in Lingding Estuary of Pearl River and adjacent inner shelf. The longitudinal net circulations which were mainly formed by the upper layer of fluids composed of estuarine brackish water and the lower layer flow compensated from the high salinity inner shelf water moved downestuary, and stretched onto the shelf while strengthend when the high discharges encounterd with strong wind coming from the southwest.The calculated results showed that the net circulation was the principal effect on longitudinal net salinity fluxes for the July section, and the net advection controlled the downestuary salinity fluxes in the other season sections. The suspended sediment fluxes were mainly controlled by net advection and tidal pumping and the flux intensity by tidal pumping was closely related with the spring or neap tides.