1. s s Wind-induced circulation
The wind-induced circulation can compete with estuarine circulation, or act in concert
The wind-induced circulation will depend on stratification:
depth-dependent under stratified conditions
weak depth-dependence under homogeneous conditions s
Weak
Depth-Averaged
Transport s
Large
Depth-Mean
Transport

2. sx Wind-Induced Surface Slope
Can be assessed from the vertical integration of the linearized u momentum equation,
with no steady state:
Note that a westward sx (negative) produces a negative slope.
sx x1 x2 y x x1 x2 
Wind will pile up water in the direction toward which it blows.

5. The perturbation produced by the wind propagates into the estuary and may cause seiching if the period of the perturbation is close to the natural period of oscillation: H H

6. Bathymetry effects on wind-induced flow
non-dimensionalized momentum balance:
non-dimensional variables:
subscript indicates dimensional variables
boundary conditions
Integrating twice and applying boundary conditions:

7. volume transport
no net volume transport

8. Along the Estuary: Pressure Gradient + Friction
Winant (2004)
Along the Estuary: Pressure Gradient + Friction
Across the Estuary: Pressure Gradient + Friction

9. X t ROMS (full dynamics) Homogeneous fluid with rotation Sanay &
Valle-Levinson (2005)
ROMS
(full dynamics)
Homogeneous fluid
with rotation
(red is downwind;
blue is upwind)

10. Particle trajectories
(high E)
(low E)
(high E)
(low E) y x y z y x y z
Particle trajectories
Winant (2004)

11. t Examples of bathymetric effects on wind-induced flow
Looking into lagoon
Red = Water going out
Blue = Water going in

12. Non- dimensional depth

13. Residual Flow at Bahía Concepción, Chile
(looking seaward)

18. Along the Estuary: Pressure Gradient + Friction
Wind-induced flow
[Wong, 1994; JGR; No. 99, p.14209]
Local Wind Effects
Remote Wind Effects
Along the Estuary: Pressure Gradient + Friction