[MITgcm-support] low eta_min

[Neil Patel]

I’m having an issue with certain parts of the ocean getting unrealistically low sea surface height (< -20 m). I can’t figure out what the cause might be, perhaps I have an error in my input and forcing files (believed I checked them thoroughly) or an improper setting. The low sea surface heights are always at the Arctic coast (mostly near Scandivinia) and a few spots on the coast of Antarctica. Perhaps it has something to do with sea ice, since both locations are near a sea ice edge? [I have the sea ice package enabled]. I don’t think the cause is due to too high of a time step, as I’m running at a very low time step for testing purposes (100 second at 1/6°). And the advcfl parameter stays low enough (below 0.05), so that would imply the time step isn’t an issue.

Here are some parameters I set in my input/data file (I think only a few are relevant, but I’m pasting more just in case). Anyhow if there is anything that anyone could suggest checking as a possible cause, I appreciate it!

Thanks,

Neil

viscAr= 5.6614e-04,
no_slip_sides=.FALSE.,
no_slip_bottom=.TRUE.,
rhonil=1027.5,
rhoConstFresh=999.8,
eosType='JMD95Z',
hFacMinDr=50.,
hFacMin=0.3,
hFacInf=0.1,
hFacSup=5.,
select_rStar=2,
nonlinFreeSurf=3,
implicitDiffusion=.TRUE.,
implicitViscosity=.TRUE.,
viscC4Leith=1.5,
viscC4Leithd=1.5,
viscA4GridMax=0.5,
useAreaViscLength=.TRUE.,
sideDragFactor=0.,
highOrderVorticity  = .TRUE.,
bottomDragQuadratic = 0.0021,
tempAdvScheme=7,
saltAdvScheme=7,
StaggerTimeStep=.TRUE.,
multiDimAdvection=.TRUE.,
vectorInvariantMomentum=.TRUE.,
implicitFreeSurface=.TRUE.,
exactConserv=.TRUE.,
debuglevel=-1,
convertFW2Salt=-1
useRealFreshWaterFlux=.TRUE.,