[MITgcm-support] KPP and MLDs questions

[Lars Czeschel]

Hi Galen,

Wich kind of surface forcing do you use?

In an 1*1 North Atlantic setup I first use
prescribed heat fluxes (NCEP) + SST restoring (WOA98)
which results in much too
deep MLDs in late winter, regardless of using
kpp, implicit diffusion or just convective adjustment.

The situation changed after using bulk 
formulae with prescribed spec. humidity,
air temperature, long- and shortwave radiation.
(no SST restoring!) 

ECCO_CPPOPTIONS.h:
#define  ALLOW_ATM_TEMP
#undef  ALLOW_ATM_WIND
#define ALLOW_BULKFORMULAE

For example, the maximum MLD's in the 
central LabSea decreases from 4000m to
1500m.

Lars

--------------------------
Lars Czeschel
Department of Meteorology
University of Reading
PO Box 243
Reading RG6 6BB











On Tue, 2006-06-27 at 10:41 -0500, Galen McKinley wrote:
> Dear all -
> 
> Stephanie, Dave, Val and I are trying to get our mixed layer depths correct
> in our new 0.5x0.5 North Atlantic setup. Right now they seem too deep in
> comparison to WOA01 data.
> 
> At the same time, we are trying to understand how the KPP HBL and the MLD
> relate to each other. It seems that the KPP HBL has the potential for a lot
> more variation with time over a month, but the MLD is going to be a more
> integrated measure of vertical homogenization. This suggests the KPP HBL
> monthly mean should be shallower than the MLD, which is indeed what we find.
> Do you agree with this interpretation?
> 
> Since we are interested in the biogeochemistry (for example, from how deep
> were nutrients mixed up to the surface) I wonder if a diagnostic of maximum
> KPP HBL over a month might be a better estimate of the depth of actual
> mixing. Does this sound sensible?
> 
> Finally, any suggestions on where to start tuning KPP to make the MLDs a bit
> shallower? 
> 
> Thanks for your help,
> Galen
> 
> --------------------------------------------------------------------------
> Galen A. McKinley, Assistant Professor
> Atmospheric and Oceanic Sciences                         608 262 4817
> University of Wisconsin - Madison        www.aos.wisc.edu/~galen/
> --------------------------------------------------------------------------
> 
> 
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