[MITgcm-support] Problem with OBCs (bug ?)

[Nicolas Grisouard]

David (and others who have an opinion),

> I believe you need to use exf (and cal) to set time periods for 
> forcing with OBCS. So say you wish to start from 0 and after n 
> timesteps you want to have U and V on the boundary. Then you need exf 
> to set the period to n * dt.

I am a bit confused. I usually do something that looks like what you do, 
but without using the exf package. I just multiply the OBWu (as well as 
OBWw and the term added to tRef(K) in OBWt when I use these fileds) by a 
number that is time-dependent and that has been defined a few lines 
before, say (following internal_wave) :


rampTime2 = obTimeScale / 2. _d 0,
OBWu(J,K,bi,bj)= [nominal value of OBWu(J,K,bi,bj)]*{1 - exp( - 
futuretime / rampTime2)} ,



so that I would have U (, W, T) = 0 (or tRef for T) at  t=0  and the 
nominal forcing values after some forcing periods (my configurations are 
2D and I do not have V velocites).

Is any of the two methods better that the other one, and if partially, 
in which cases ?

Thanks,
Nicolas

-- 
Nicolas GRISOUARD
PhD Student - ERES division
Laboratoire des Ecoulements Geophysiques et Industriels
BP 53
38041 Grenoble cedex 9 France
tel : +33 (0)476 825 037 - fax : +33 (0)476 825 271