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

[Jody Klymak]

Hello,

Oops, it was equally silly:

delX = 200., is *not* the same as
delX = 100*200.,

It is dx = [200 99*1.234567e5].  That explains a lot...

Sorry for the chatter.

Cheers,  Jody

On Oct 5, 2006, at 2:07 PM, Jody Klymak wrote:

>
> Hi Dmitri,
>
> Yes, the first and last depths in X are zero.
>
> I should mention that I have only one grid point in y.  Is that OK,  
> or could it cause the surface algorithm to have difficulties?
>
> Thanks,  Jody
>
> On Oct 5, 2006, at 1:56 PM, Dmitri Leonov wrote:
>
>> 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/
>>>
>>>
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>
>>
>> -- 
>> ------------------------------------------------
>> Dmitri A. Leonov
>> Research Associate, Postdoctoral
>> University of Washington, School of Oceanography
>>
>>
>> _______________________________________________
>> MITgcm-support mailing list
>> MITgcm-support at mitgcm.org
>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>
> --
> Jody Klymak
> http://web.uvic.ca/~jklymak/
>
>
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
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--
Jody Klymak
http://web.uvic.ca/~jklymak/