[MITgcm-devel] seaice lsr

[Martin Losch]

Hi there,

I have found that the LSR solver is a little inconsistent (which  
causes it to produce a slight assymetry with a symmetric domain and  
forcing):
the following lines:
>           URT(I,J)=FXY(I,J,bi,bj)+AA3
>      &          +UVRT1(I,J,bi,bj)*uIce(I,J-1,1,bi,bj)
>      &          +UVRT2(I,J,bi,bj)*uIce(I,J+1,1,bi,bj)
(and the corresponding ones for the vice equation) within a J-loop  
cause URT to be computed from the updated uIce(I,J-1,1,bi,bj) and the  
not yet updated uIce(I,J+1,1,bi,bj) (=uIce(I,J+1,3,bi,bj) at this  
time). One could replace these lines by:
>           URT(I,J)=FXY(I,J,bi,bj)+AA3
>      &          +UVRT1(I,J,bi,bj)*uIce(I,J-1,3,bi,bj)
>      &          +UVRT2(I,J,bi,bj)*uIce(I,J+1,3,bi,bj)
which changes the results (lab_sea fails with cg2d=10), but then the  
solution is symmetric, when it should be. Also this formulation  
removes a dependency from the j-loop which impairs vectorization. Can  
I change that?

Martin