[MITgcm-support] Re: single layer run

[Martin Losch]

Sergey,

if you apply pressure forcing that evolves in time, then your flow 
field should also vary in time. Even if your pressure forcing is 
constant in time (and variable in space), you should reach a 
non-trivial steady state (inverted barometer effect), that should have 
something like the following balance:
f*v + g*d(ssh)/dx + (1/rho0)*dp/dx = 0 (and something similar for the 
v-momentum equation, with p=atmospheric pressure), note that the ssh 
can (and probably will) be zero in this case.
There is  a verification experiment that does this with 4 layers 
(inverted_barometer) and constant (in time) forcing. Maybe you can 
modify this experiment, or try to see what's different in your case?

What do you mean by initial sea-surface height? Do you prescribe an 
initial SSH?

Martin

On May 10, 2005, at 10:47 PM, Sergey Vinogradov wrote:

> Hi Ed:
> The pressure loading is a realistic variable forcing.
> Actually this raises the question if a single layer is a valid 
> configuration for such experiment...
> Regards
> Sergey
>
> Ed Hill wrote:
>
>> Hi Sergey,
>>
>> I've subscribed you to the MITgcm-support email list so that any
>> subsequent emails you send will get through.  And I've forwarded your
>> email below.
>>
>> In regards to your question, wouldn't one expect the ocean to reach a
>> quiescent (zero-velocity) solution if it were forced with a steady
>> atmospheric pressure?  Or are you varying the atmospheric pressure 
>> over
>> time and space?
>>
>> Ed
>>
>> === original message ===
>>
>> Hello,
>>
>> After enough playing with a global baroclinic runs, I decided to try a
>> barotropic run for which I set eosType to 'linear' and specify a 
>> single
>> layer with delZ=5000. After several timesteps, the initial sea-surface
>> height in the open ocean just dies to zero, while the initial ssh 
>> along
>> the coasts stays the same. No other terms have been changed from the
>> baroclinic experiment setup. Any suggestions how to make it run will 
>> be
>> greatly appreciated. I forgot to mention that I force the model with
>> atmosperic pressure only.
>>
>> Regards,
>> Sergey Vinogradov
>>
>>
>>
>
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support
>
Martin Losch // Alfred-Wegener-Institut für Polar- und Meeresforschung
Postfach 120161, 27515 Bremerhaven, Germany
mailto:mlosch at awi-bremerhaven.de // Tel./Fax: ++49(471)4831-1872/1797
http://www.awi-bremerhaven.de/People/show?mlosch