[MITgcm-devel] another bug in growth.F ?
Jinlun Zhang
zhang at apl.washington.edu
Mon Dec 4 21:39:19 EST 2006
Martin,
I would vote run45.png for best performance except that the summer ice
is slightly overestimated. I would not vote run41.png because of its
weird snow distribution. The snow pattern should generally follow the
ice pattern (could mean a problem with ice advection). I don't know why
the snow gets so thick with run40.png, the precip forcing could be way
off. But obviously snow advection helps a lot. Snow flooding, if it
overestimates ice, then turn it off, not big deal (since what we do is
to make the fields look like observations). As for thsice, I don't know
what is going on. But for any ice thermodynamics that involves ice
salinity (if thsice uses ice salinity), there might be a singularity in
the formulation (I had such feeling before, but I could be wrong).
Jinlun
Martin.Losch at awi.de wrote:
>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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>>>>
>>>>
>>>_______________________________________________
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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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>>
>>
>>
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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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