Longitudinal Transportation Mechanism of Sallinity in West Channel of Lingding Bay in Dry Season, China

Abstract

Estuary is the transition zone,where fresh water and salty water mixes strongly.In dry season,because Discharge of the Pearl River water decreases,salt water intrusion become serious in the Pearl River delta,and affect the safety of fresh water supply.So,salinity transport mechanism is a very important topic.In this paper,according to the measured data in November 3-4,2005,calculate and analyze the longitudinal flow characteristics,salinity distribution and transport mechanisms. Research results show that the velocity varieties with ebb and flood processes,the surface velocity is larger than that of bottom and middle layer.In ebb slack and flood slack period,there is a zero velocity point,and its movement distance is up to 10km.Vertical residual circulation is obvious, surface layer is to sea,and bottom layer is to land.Net salinity transport direction is from sea to land.salinity vertical stratification is evident,and varieties obviously with tide changes.Surface salinity gradient is larger In flood period,and bottom salinity gradient is larger in ebb period.In ebb slack time,salinity is vertical uniform distribution.