[MITgcm-devel] GM + KPP and non-local term

[Jean-Michel Campin]

Hi,

I think there is a problem in the KPP non local term:
taking for example kpp_transport_t.F :
>            df(i,j) = df(i,j) - _rA(i,j,bi,bj) *
>     &           KappaRT(i,j,k) * KPPghat(i,j,km1,bi,bj) *
>     &           ( surfaceForcingT(i,j,bi,bj)
               
should not be KappaRT(i,j,k) but instead KPPdiffKzT(i,j,k,bi,bj)

If I want to use GM and KPP, KappaRT contains 2 parts:
the KPP part (=KPPdiffKzT) and the GM part (= Kwz).

1) I don't see why the non local term should have a contribution
coming from GM-Redi (they are meant to represent 2 different 
processes) and 
2) I see how this KappaRT can generate problems, because 
KPP does not know anything about what GM will predict for Kwz,
Kwz can perfectly be very large, and in this case
the non-local term (that is always treated explicitly) 
might perfectly be very large also, leading to instabilities.

Can someone who knows something about KPP implementation 
comment about this point ?

Thanks,

Jean-Michel