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. Wind-driven flow and bathymetric effects
non-dimensionalized momentum balance:
non-dimensional variables:
subscript indicates dimensional variables
boundary conditions
Integrating twice and applying boundary conditions:

6. volume transport
no net volume transport

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

8. 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)

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

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

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

15. Matlab code
Winant’s (2004)
clear all
close all
[y,z]=meshgrid(-1:.05:1,-1:.05:0);
h=1-abs(y); % bathymetry
y1=y(1,:); h1=h(1,:); % first row of ‘y’ and ‘z’
dn=1.5*mean(h1.^2)/mean(h1.^3); % d eta/dx
u=dn*(z.^2-h.^2)/2+z+h; % u matrix
ll=[-4,-3,-1,-.25,-.2,0]; % contour intervals to plot an label
colormap pink
contourf(y,z,u,ll)
hold on
contour(y,z,u,'ShowText','on','LineWidth',1.,'LineColor',[0 0 0])
fill([-1,y1,1],[-1,-h1,-1],'w')