|Salt dynamics in well-mixed estuaries: importance of advection by the tides|
Wei, X.; Schramkowski, G.P.; Schuttelaars, H.M. (2014). Salt dynamics in well-mixed estuaries: importance of advection by the tides, in: Proceedings of the 17th physics of Estuaries and Coastal Seas (PECS) conference, Porto de Galinhas, Pernambuco, Brazil, 19–23 October 2014. pp. [1-4]
In: (2014). Proceedings of the 17th physics of Estuaries and Coastal Seas (PECS) conference, Porto de Galinhas, Pernambuco, Brazil, 19–23 October 2014. [S.n.]: [s.l.].
Tidal advective diffusion; Salt transport; Well-mixed; Estuaries
|Auteurs|| || Top |
- Wei, X.
- Schramkowski, G.P.
- Schuttelaars, H.M.
Understanding salt dynamics is important to adequately model salt intrusion, baroclinic forcing and sediment transport. In this contribution, we focus on the importance of the salt transport by tidal advection in a well-mixed estuary. The water motion is resolved in a consistent way with a width-averaged analytical model for a converging estuary, coupled to the salt dynamics. The model reveals that salinity to the lowest order is time-independent and vertically homogeneous, and that the leading order residual salt transport is driven by horizontal diffusion, river outflow, and tidal advection resulting in an effective diffusive contribution. The contribution of tidal advective transport of salinity is explicitly calculated and the sensitivities of this contribution to friction, river discharge, and estuarine shape factors are investigated. The main findings are that the advective transport gives an important contribution in case of large slip parameter, moderate eddy viscosity coefficient, moderate convergence length, and moderate estuarine water depth. Using the balance discussed in this paper, the total diffusion Kx is obtained from the measured salinity data. This is used to show the relative importance of the tidal advection of salinity in maintaining the observed salinity distribution. As an application, the Delaware estuary is studied using the present model, and the tidal advective diffusion is found to be an important driving mechanism for landward salt transport for low to moderate river outflow.