[MITgcm-support] seaice and surfaceTendencyTice

[Martin Losch]

Hi,

I have a quick question about the seaice model, which I might use in 
the near future:
In forward_step it is written:
> C--   Call sea ice model to compute forcing/external data fields.  In
> C     addition to computing prognostic sea-ice variables and 
> diagnosing the
> C     forcing/external data fields that drive the ocean model, 
> SEAICE_MODEL
> C     also sets theta to the freezing point under sea-ice.  The implied
> C     surface heat flux is then stored in variable surfaceTendencyTice,
> C     which is needed by KPP package (kpp_calc.F and kpp_transport_t.F)
> C     to diagnose surface buoyancy fluxes and for the non-local 
> transport
> C     term.  Because this call precedes model thermodynamics, 
> temperature
> C     under sea-ice may not be "exactly" at the freezing point by the 
> time
> C     theta is dumped or time-averaged.
In the root-directory I do a grep on surfaceTendencyTice
> csysm3::MITgcm> grep -i surfaceTendencyTice ./*/*/*.F
> ./model/src/forward_step.F:C     surface heat flux is then stored in 
> variable su
> ./pkg/kpp/kpp_calc.F:     &                            
> SurfaceTendencyTice(i,j,b
> ./pkg/kpp/kpp_transport_t.F:     &         
> SurfaceTendencyTice(i,j,bi,bj) -
> ./pkg/seaice/growth.F:C surfaceTendencyTice is the equivalent amount 
> of surface
> ./pkg/seaice/growth.F:          
> surfaceTendencyTice(I,J,bi,bj)=YNEG(I,J,bi,bj)/d
> ./pkg/seaice/seaice_init.F:          surfaceTendencyTice(i,j,bi,bj) = 
> ZERO
> ./pkg/seaice/seaice_model.F:       _EXCH_XY_R4(surfaceTendencyTice, 
> myThid )
In external_forcing_surf surfaceTendencyTice does not appear.
Now my question: Why is surfaceTendencyTice only relevant to KPP? If 
the surface heat flux implied by surfaceTendencyTice is supposed to set 
the surface ocean temperature to freezing, shouldn't this appear in 
surfaceTendencyT to have an effect on theta other than the mixing due 
to KPP? Or am I missing something?

Martin



Martin Losch // mailto:mlosch at awi-bremerhaven.de
Alfred-Wegener-Institut für Polar- und Meeresforschung
Postfach 120161, 27515 Bremerhaven, Germany
Tel./Fax: ++49(471)4831-1872
http://www.awi-bremerhaven.de/People/show?mlosch