[MITgcm-devel] another bug in growth.F ?
Martin.Losch at awi.de
Martin.Losch at awi.de
Mon Dec 4 15:49:56 EST 2006
Oops, sorry, Jinlun. All the figures are in http://mitgcm.org/~mlosch :
http://mitgcm.org/~mlosch/run40.png
http://mitgcm.org/~mlosch/run41.png
http://mitgcm.org/~mlosch/run42.png
http://mitgcm.org/~mlosch/run43.png
http://mitgcm.org/~mlosch/run44.png
http://mitgcm.org/~mlosch/run45.png
http://mitgcm.org/~mlosch/run46.png
M.
Martin Losch
Alfred Wegener Institute
Postfach 120161, 27515 Bremerhaven, Germany;
Tel./Fax: ++49(0471)4831-1872/1797
----- Original Message -----
From: Jinlun Zhang <zhang at apl.washington.edu>
Date: Monday, December 4, 2006 6:10 pm
Subject: Re: [MITgcm-devel] another bug in growth.F ?
> Hi Martin,
>
> Where do you put the figures? I only see netcdf files from the links.
>
> Jinlun
>
> Martin Losch wrote:
>
> > More on seaice/thsice.
> >
> > I have put a few results of my 2deg experiment (to 80N), forced
> with
> > CORE (modified NCAR/NCEP reanalysis) climatology:
> >
> > http://mitgcm.org/~mlosch/run40
> > http://mitgcm.org/~mlosch/run41
> > http://mitgcm.org/~mlosch/run42
> > http://mitgcm.org/~mlosch/run43
> > http://mitgcm.org/~mlosch/run44
> > http://mitgcm.org/~mlosch/run45
> > http://mitgcm.org/~mlosch/run46
> >
> > runs 40,41,42,45 are with seaice and growth-thermodynamics, runs
> > 43,44,46 with seaice+thsice. All netcdf files are 10day averages
> in
> > the 101st year of integration, except for run43, which crashes at
>
> > some time in the 6th decade, so that the netcdf files contains
> the
> > 51st year. I use asynchronous timestepping
> > (deltaTtracer=12h,deltaTmom=20min) for all runs. there are also
> > figures with appropriate files name (run40.png, etc) showing
> > effective snow and ice thickness and ice concentration in march
> and
> > august for the antarctic ocean. Details:
> > run40, not advection of snow, flooding (also included grid.*
> files).
> > Here you see the strange snow patterns, where snow is as high as
> 160m
> > (not included in colorscale), and depresses the sea surface by as
>
> > much as 160m*0.33.
> > run41, advection of snow (scheme 2 for all variables): advection
> > distributes the snow and thing look more physical
> > run42, advection of snow (scheme 2 for all variables),
> flooding=true:
> > a lot less snow but much more ice, too much if you ask me.
> > run45, advection of snow and flooding, but advection scheme 1 for
> all
> > variables: the different advection schemes makes the solution
> > smoother, but not better, as expected.
> > run43, with thsice as is in the repository (crashed during the
> 6th
> > decade, don't know why), this version of the code should probable
>
> > vanish pretty soon? tiny concentrations/thicknesses at the ice
> margins> run44, with thsice and JMC's "new version" in
> seaice_advdiff.F: too
> > be compared with run45. thsice leads to even more ice than the
> > simpler thermodynamics of run45. Thickness is way too high
> (compare
> > with www.seaice.de), and in summer the Eastern Weddell Sea should
> be
> > almost ice free (only some ice along the Peninsula).
> > run46, like run44, but flooding turn off (commented out in
> > thsice_calc_thickn.F): the flooding algorithm has less of an
> impact
> > on the solution than for growth.
> >
> > For a comparision with observations of concentrations see
> > www.seaice.de, eg. March15, 2006 (from AMSR-E):
> > http://iup.physik.uni-
> bremen.de:8084/amsredata/asi_daygrid_swath/l1a/
> > s6250/2006/mar/asi-s6250-20060314-v5_nic.png
> > Aug15,2006
> > http://iup.physik.uni-
> bremen.de:8084/amsredata/asi_daygrid_swath/l1a/
> > s6250/2006/aug/asi-s6250-20060815-v5_nic.png
> >
> > same dates in 1999 from SSMI
> > http://iup.physik.uni-bremen.de:8084/archive/south/1999/19990315.png
> > http://iup.physik.uni-bremen.de:8084/archive/south/1999/19990815.png
> >
> > So, as far as I can see, the model produces first order
> distriubtions
> > in all cases with too much extend in summer, too much ice in
> general
> > and too much snow. Not too bad, but how much of this do we
> expect.
> > I'll go and consult with my trusty ice specialists. But maybe
> someone
> > on this list can comment too (Jinlun?)
> >
> > Martin
> >
> > On 30 Nov 2006, at 17:37, Martin Losch wrote:
> >
> >> Hi Dimitris and others,
> >>
> >> I have no 100year of running my 2deg configuration with
> isotropic
> >> grid in the southern hemisphere for 41 different parameter
> >> combinations/code versions. Here is my superficial summary:
> >> 1. The crucial fix for the sea ice distribution (AREA+HEFF) is
> the
> >> evap*(1-area) fix. I think we can agree on that
> >> 2. If snow is not advected or turned into ice by submersion
> >> (flooding algorithm), it accumulates at rates of more than 1m/y
> >> consistent with the surface forcing (precipitation) provided by
> the
> >> CORE climatology. This happens only in areas with perennial ice
> >> cover and only in the southern hemisphere (my domain stops at
> 80N).
> >> The pattern of snow accumulation is a little strange, which is
> the
> >> straw that I cling to in thinking that there is still a bug in
> the
> >> handling of snow in growth (see attached figure for a typical
> >> pattern, run40).
> >> 3. If I use flooding but no advection of snow, the snow look OK,
> but
> >> there is far too much ice (thickness), especially in summer
> (area),
> >> run38 in a previous figure.
> >> 4. If I use advection of snow but no flooding, the snow is
> >> distributed and can melt (I guess), run41 in attached figure.
> There
> >> is still a litte too much snow after 100 year (3.6m in a few
> areas
> >> west of the Antarctic peninsula, but I could live with that). Be
>
> >> aware that the advection I use is the 2nd order (default)
> advection,
> >> and I am afraid, that the advection of snow is not properly
> done in
> >> this case, but that should be a minor issue. Ice looks
> reasonable in
> >> this case maybe a little thin in a few areas in summer, but
> appears
> >> to be problem of the 0-layer thermodynamics, I guess.
> >> 5. What will happen with flooding and advection of snow I don't
> know
> >> yet (not part of my 41 different combinations), but tomorrow
> (will
> >> this be run42?).
> >>
> >> So my preliminary conclusions are:
> >> 1. The snow is still not handled properly in growth/seaice_advdiff
> >> 2. with advection of snow the problems are smallest (may be even
>
> >> smaller with additional flooding)
> >>
> >> Martin
> >>
> >> <snow4041.png>
> >>
> >> On 30 Nov 2006, at 16:49, Dimitris Menemenlis wrote:
> >>
> >>> Jinlun, the beer/crap comment was in jest. Everyone who has
> used
> >>> pkg/seaice appreciates your effort in making this package
> available
> >>> to MITgcm and also your subsequent help with bug fixes and
> with
> >>> other modifications.
> >>>
> >>> Martin, I also find that
> >>>
> >>>> cdm IF(FICE(I,J,bi,bj).GT.ZERO) THEN
> >>>> IF(atemp(i,j,bi,bj).LE.273.15 _d 0 ) THEN
> >>>
> >>>
> >>> has very little impact on growth.F both for the forward
> solution as
> >>> well as for the high forward sensitivity of the model that you
> and
> >>> Patrick reported. What does remove the high forward
> sensitivity is
> >>> commenting out the snow-melt addition.
> >>>
> >>>> C Now melt snow if there is residual heat left in surface
> >>>> level C Note that units of YNEG and
> SEAICE_SALT
> >>>> are m of ice cdm IF(RESID_HEAT
> >>>> (I,J,bi,bj).GT.ZERO.AND. cdm
> >>>> & HSNOW(I,J,bi,bj).GT.ZERO)
> >>>> THEN cdm
> GHEFF(I,J)=MIN
> >>>> (HSNOW(I,J,bi,bj)/SDF/ICE_DENS, cdm
> >>>> & RESID_HEAT
> >>>> (I,J,bi,bj)) cdm
>
> >>>> YNEG(I,J,bi,bj)=YNEG(I,J,bi,bj)+GHEFF
> >>>> (I,J) cdm
> HSNOW(I,J,bi,bj)=HSNOW
> >>>> (I,J,bi,bj)-GHEFF(I,J)*SDF*ICE_DENS cdm
> >>>> SEAICE_SALT(I,J,bi,bj)=SEAICE_SALT(I,J,bi,bj)-GHEFF
> >>>> (I,J) cdm ENDIF
> >>>
> >>>
> >>> So back to where we were before latest exchange.
> >>>
> >>> Dimitris
> >>>
> >>> --
> >>> Dimitris Menemenlis <menemenlis at jpl.nasa.gov>
> >>> Jet Propulsion Lab, California Institute of Technology
> >>> MS 300-323, 4800 Oak Grove Dr, Pasadena CA 91109-8099
> >>> tel: 818-354-1656; fax: 818-393-6720
> >>> _______________________________________________
> >>> MITgcm-devel mailing list
> >>> MITgcm-devel at mitgcm.org
> >>> http://mitgcm.org/mailman/listinfo/mitgcm-devel
> >>
> >>
> >> _______________________________________________
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> >> http://mitgcm.org/mailman/listinfo/mitgcm-devel
> >
> >
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>
>
> --
>
> Jinlun Zhang
> Polar Science Center, Applied Physics Laboratory
> University of Washington, 1013 NE 40th St, Seattle, WA 98105-6698
>
> Phone: (206)-543-5569; Fax: (206)-616-3142
> zhang at apl.washington.edu
> http://psc.apl.washington.edu/pscweb2002/Staff/zhang/zhang.html
>
>
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