[MITgcm-support] Doing a channel+surface pressure

[Yuan Lian]

Hi, Jean-Michel,

Thanks a lot for the suggestion on doing a channel, I will try this soon.
Still I have a little problem to make a balanced gradient flow. I have
defined the initial wind profile on isobars which has only one component
(only zonal wind but no meridional wind and vertical wind, that is,
v=w=0), I tried to use extrapolation:
(lnP(0)-lnP(1))/(PHI(0)-PHI(1))=(lnP(2)-lnP(1))/(PHI(2)-PHI(1))
at the bottom of the atmosphere (1bar level for the Earth's atmosphere),
where P(0) is the surface pressure, P(1) and P(2) are isobars above the
surface, and PHI(1), PHI(2) are geopotential along the P(1) and
P(2) isobars. However, the preesure gradient is greater than coriolis
force. So the questions here are:

1. I have done the balanced wind if the surface pressure is zero, I
calculated the potential temperature distribution corresponding to the
given wind profile, in this case, pressure gradient can be balanced well
with coriolis force and curvature force. How to calculate the surface
pressure by given wind profile along isobars if surface pressure won't be
zero?

2. I found a sponge layer is very helpful to stabilize the winds at polar
region, is there any standard module to add sponge layer for atmosphere?(I
have done a sponge layer, however it will be nice to have a module to do
sponge layer so I won't mess up the source code)


Greatly appreciate for your kind help!

Best regards,
Yuan