[MITgcm-devel] lsOr

[Martin Losch]

Hi Jinlun,

I have a question about LSOR. Obviously I have never worried about the "O" in LSOR, in fact all the subroutines are just called lsr or seaice_lsr, right?
But the O stands for overrelaxation and in your Zhang+Hibler (1997) you show that the overrelaxation parameter omega is optimally set to 1.7 or 1.8.

In the MITgcm this parameter is (was) hard wired to 0.95 (WFAU = WFAV = 0.95, in lsr.F and by virtue of copying seaice_lsr.F). This is clearly UNDERrelaxation. 
Can you remember, why this value is used? Do we need omega<1 to stabilize the system?
What do you normally use in your model?

Martin