[MITgcm-support] Spinup in a 2-D channel surface waves?

[Dmitri Leonov]

Does your topography go all the way to the surface? (Otherwise your 
channel will be periodic in the cross-channel direction).
That's the only hint I can think of right now.

Dmitri

Jody Klymak wrote:
>
> Hello,
>
> I want to perform spinup of a 2-D channel to along-channel winds for a 
> class I'm teaching.  While I'm sure the MITgcm is overkill for this, 
> I'm at least vaguely familiar with it.
>
> I have the winds blowing, the channel seems to behave, and an Ekman 
> layer seems to form.  However, the surface pressure is not behaving 
> and I'm finding the docs on the surface pressure solver opaque enough 
> that I thought I'd ask for help here.
>
> My vertical resolution near the surface is 0.75m, for 40 bins.  The 
> total water depth is as deep as 200 m, with sloping sides in a 20 
> km-wide channel.  dx = 200 m.
>
> What happens is I blow a south wind, the Ekman layers pile water up in 
> the west and move it away from the East. However, the depth anomalies 
> do not seem to get large enough, and the ones that do form
> do not propagate more than a couple of grid cells away at anything 
> like the surface wave speed.  For instance, the cross-channel Ekman 
> flux reaches 1 m^2/s, which should be changing the surface tilt by 
> something like 36 cm over an hour. However, after 7 h or so (in sim 
> time), I still have 10 cm-high anomalies in the grids adjacent to the 
> edge of the channel, and nothing more than 3 grid cells away.
>
> Any hints what I've done wrong or suggestions for getting the 
> barotropic pressure gradient to set up properly across the channel 
> would be very helpful!
>
> Thanks a lot,  Jody
>
> In "data" I hope the relevant parameters are:
>
> viscAz=1.E-3,
> viscAh=1.E-3,
> no_slip_sides=.FALSE.,
> no_slip_bottom=.TRUE.,
> viscA4=0.E12,
>
> gBaro=9.81,
> rigidLid=.FALSE.,
> implicitFreeSurface=.TRUE.,
>
> nonHydrostatic=.FALSE.,
> hFacMin=0.5,
> implicSurfPress=0.5,
> implicDiv2DFlow=0.5,
> nonlinFreeSurf=3,
> hFacInf=0.1,
> hFacSup=2.0,
> exactConserv=.TRUE.,
>
>
>
>
> -- 
> Jody Klymak
> http://web.uvic.ca/~jklymak/
>
>
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-- 
------------------------------------------------
Dmitri A. Leonov
Research Associate, Postdoctoral
University of Washington, School of Oceanography