[MITgcm-support] The growth rate of sea ice
weijianfen1988 at 163.com
weijianfen1988 at 163.com
Mon Nov 2 20:46:14 EST 2015
Hi everyone,
Thank you for the answer from Professor Martin Losch. So the net growth rate of ice concentration is SIdA (SIdA = SIdAbATO + SIdAbATC + SIdAbOCN), which equals the (SIarea - SIareaPT)/deltaT. And the net growth rate of ice thickness is (SIdHbATO + SIdHbATC + SIdHbOCN + SIdHbFLO), which equals the (SIheff - SIheffPT)/deltaT. Are they right?
Thank you very much.
Jianfen
weijianfen1988 at 163.com
From: mitgcm-support-request
Date: 2015-11-02 23:35
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Today's Topics:
1. Re: seaice anomalous advection in doubly periodic domain
(Martin Losch)
2. Re: seaice anomalous advection in doubly periodic domain
(Ryan Abernathey)
3. Re: The growth rate of sea ice (Martin Losch)
----------------------------------------------------------------------
Message: 1
Date: Mon, 2 Nov 2015 16:22:22 +0100
From: Martin Losch <Martin.Losch at awi.de>
To: MITgcm Support <mitgcm-support at mitgcm.org>
Subject: Re: [MITgcm-support] seaice anomalous advection in doubly
periodic domain
Message-ID: <EC4BC9F0-370C-4F70-820D-2DAC25AC286F at awi.de>
Content-Type: text/plain; charset="utf-8"
Hi Jean,
the LSR solver just has this issue that you stumbled over. In each non-linear iteration it solves a linearized set of equations by iteratively solving many tridiagonal systems locally on each tile, and these tridiagonal solvers require boundary values from the neighboring tiles (of the previous iteration step). If convergence (of the linearized system) is not reached (because the required tolerance is low, or there are not enough iterations allowed) the edge effects remain. You should be able to get rid of these stripes by decreasing LSR_ERROR (usally 1e-6 is enough, but that makes the model much slower). Alternatively you can improve the situation by increaseing the number of non-linear iterations ( NPSEUDOTIMESTEPS>2, e.g. 10 ), or you could increase the overlap from zero:
SEAICE_OLx = 1
SEAICE_OLy = 1
(requires OLx=3, OLy=3, because the the LSR solver requires 2 overlap points, but with advection 33 you should have that anyway, basically SEAICE_OLx <= OLx-2)
In my experience, you can reduce these edge effects sufficiently well, so that they do not (visibly) affect you simulation.
Alternatively you can try a different solver, e.g. the JFNK solver (unfortunately quite expensive) and the EVP solver (in its pure form EVP is likely to produce noise, so use the EVP* version, see recent documentation: <http://mitgcm.org/public/r2_manual/latest/online_documents/node254.html#SECTION00762460000000000000>)
I think your first question is unrelated and purely physical: in a doubly periodic domain it?s probably easier to resist deformation and to move the infinite ice cover according to some mean wind forcing (check if your wind forcing has a non-zero mean). You can test that by introducing walls or islands somewhere in the domain.
Martin
P.S. personally I would use SEAICE_EPS = 2e-9 or smaller (recent code has SEAICE_deltaMin as a replacement for this parameter), to give a little stronger ice.
P.P.S. I hope that Ryan forgives me for contradicting, but even though the VP rheology was originally meant for large scales, it appears to work very well at very high resolution, i.e. the simulated fields show very realistic deformation statistics. There appears to be some controversy in the community, and this is not yet settled.
> On 29 Oct 2015, at 17:58, Ryan Abernathey <ryan.abernathey at gmail.com> wrote:
>
> Hi Jean,
>
> I think I remember Georgy Manucharyan encountered similar problems with sea ice on tile boundaries.
>
> I don't know too much about the details of the sea ice model. But I do know that the sea ice viscous plastic rheology applies to the large-scale sea ice field (>100 km scales) is is very likely completely inaccurate for the 1km scales you are trying to model. This is a serious limitation for high-resolution ice-ocean modeling, and there is no obvious way around it until a completely new type of floe-scale sea ice model can be developed.
>
> That being said, there are lots of people on this list doing such modeling (e.g. Dimitris). Maybe you can get some answers from them.
>
> -Ryan Abernathey
>
>
> On Thu, Oct 29, 2015 at 11:34 AM, Jean Mensa <jean.mensa at yale.edu> wrote:
> Hello list,
> I am trying to setup an idealized ocean simulation with sea ice using the SEAICE package. The domain is a doubly periodic box (400km by 200km) which I force with a semi-idealized ECMWF forcing. Forcing is periodic in time (and space) and seems to generate the expected seasonal cycle of ice thickness and concentration. Nevertheless there seems to be something wrong with the ice advection.
>
> 1 - ice velocities follow wind forcing for a while, and then, as ice starts growing (not sure if that is a coincidence), they stop being affected by wind forcing and transition to steady state as if purely driven by ice inertia. Ice moves at a reasonable speed, it just goes to steady state. I am not sure whether this is a numerical/physical problem or an consequence of the doubly periodic setup.
>
> 2 - ice growth shows anomalous growth at the boundaries of the partitioning tiles. This results in a distinguishable thickness anomaly. Currently I use the same advection scheme than for tracers, a 3-rd order flux-limiter (33), and the problem persists when switching to a smaller stencil.
>
> I am not sure whether the two problems are linked or not. The second one looks like a numerical issue but the first one could be due to my particular setup.
> Any idea on what's going on?
> Thanks!
>
> It follows my data and data.seaice files,
>
> ############# DATA
>
> # Model parameters
> # Continuous equation parameters
> &PARM01
> no_slip_bottom=.FALSE.,
> eosType='JMD95P',
> diffKhT=0,
> diffKzT=0,
> rotationPeriod=86400.,
> beta=0,
> f0=1.4e-4,
> gravity=9.81,
> rigidLid=.FALSE.,
> implicitFreeSurface=.TRUE.,
> implicitViscosity = .TRUE.,
> implicitDiffusion = .TRUE.,
> tempAdvScheme=33,
> saltAdvScheme=33,
> viscC2Leith=1.0,
> staggerTimeStep=.TRUE.,
> nonHydrostatic=.FALSE.,
> readBinaryPrec=64,
> &
> # Elliptic solver parameters
> &PARM02
> cg2dMaxIters=1000,
> cg2dTargetResidual=1.E-7,
> &
> # Time stepping parameters
> &PARM03
> endTime=189216000,
> deltaTmom=240.0,
> deltaTtracer=240.0,
> abEps=0.1,
> pChkptFreq=8640000.0,
> chkptFreq=1728000.0,
> dumpFreq=86400.,
> monitorFreq=864000.,
> forcing_In_AB = .FALSE.,
> pickupStrictlyMatch = .TRUE.,
> &
>
> # Gridding parameters
> &PARM04
> usingCartesianGrid=.TRUE.,
> usingSphericalPolarGrid=.FALSE.,
> delX=400*1000,
> delY=200*1000,
> delZ=2, 2, 2, 2, 2, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 10, 10, 10, 10, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 30, 50, 50, 50, 50, 50,
> &
>
> # Input datasets
> &PARM05
> bathyFile='topo.bin',
> hydrogThetaFile='theta_100_DP.bin',
> checkIniTemp=.FALSE.,
> hydrogSaltFile='salinity_100_DP.bin',
> uVelInitFile='u_100_DP.bin',
> vVelInitFile='v_100_DP.bin',
> &
>
>
> ############# DATA.SEAICE
>
> &SEAICE_PARM01
> SEAICEwriteState = .TRUE.,
> SEAICEuseFlooding = .TRUE.,
> SEAICE_EPS = 1.E-8,
> SEAICE_area_floor = 1.E-5,
> SEAICE_area_reg = 0.15,
> SEAICE_hice_reg = 0.10,
> IMAX_TICE = 6,
> SEAICE_availHeatFrac = 0.8,
> SEAICEuseDYNAMICS = .TRUE.,
> HeffFile = 'ice_thick_S.bin',
> AreaFile = 'ice_fract_S.bin',
> SEAICEadvScheme = 33,
> useHB87StressCoupling=.TRUE.,
> &
>
> &SEAICE_PARM03
> &
>
>
>
>
>
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support
>
>
> _______________________________________________
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> http://mitgcm.org/mailman/listinfo/mitgcm-support
------------------------------
Message: 2
Date: Mon, 2 Nov 2015 10:35:32 -0500
From: Ryan Abernathey <ryan.abernathey at gmail.com>
To: "mitgcm-support at mitgcm.org" <mitgcm-support at mitgcm.org>
Subject: Re: [MITgcm-support] seaice anomalous advection in doubly
periodic domain
Message-ID:
<CAJAZx5BTRC0bkTh5_gwga=god6nm628jk0YogLM9eEOiaWwD_Q at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
> P.P.S. I hope that Ryan forgives me for contradicting, but even though the
> VP rheology was originally meant for large scales, it appears to work very
> well at very high resolution, i.e. the simulated fields show very realistic
> deformation statistics. There appears to be some controversy in the
> community, and this is not yet settled.
>
On the contrary, I would be very happy to learn that I am wrong. I am
definitely not an expert on this topic. The opinion I stated comes from
this paper, (supplemented by my own interpretation of the continuum
derivation of the sea ice equations of motion):
http://onlinelibrary.wiley.com/doi/10.1029/2008JC005182/abstract
which may now be obsolete. Have the results showing realistic deformation
statistics with VP rheology been published somewhere?
> On 29 Oct 2015, at 17:58, Ryan Abernathey <ryan.abernathey at gmail.com>
> wrote:
> >
> > Hi Jean,
> >
> > I think I remember Georgy Manucharyan encountered similar problems with
> sea ice on tile boundaries.
> >
> > I don't know too much about the details of the sea ice model. But I do
> know that the sea ice viscous plastic rheology applies to the large-scale
> sea ice field (>100 km scales) is is very likely completely inaccurate for
> the 1km scales you are trying to model. This is a serious limitation for
> high-resolution ice-ocean modeling, and there is no obvious way around it
> until a completely new type of floe-scale sea ice model can be developed.
> >
> > That being said, there are lots of people on this list doing such
> modeling (e.g. Dimitris). Maybe you can get some answers from them.
> >
> > -Ryan Abernathey
> >
> >
> > On Thu, Oct 29, 2015 at 11:34 AM, Jean Mensa <jean.mensa at yale.edu>
> wrote:
> > Hello list,
> > I am trying to setup an idealized ocean simulation with sea ice using
> the SEAICE package. The domain is a doubly periodic box (400km by 200km)
> which I force with a semi-idealized ECMWF forcing. Forcing is periodic in
> time (and space) and seems to generate the expected seasonal cycle of ice
> thickness and concentration. Nevertheless there seems to be something wrong
> with the ice advection.
> >
> > 1 - ice velocities follow wind forcing for a while, and then, as ice
> starts growing (not sure if that is a coincidence), they stop being
> affected by wind forcing and transition to steady state as if purely driven
> by ice inertia. Ice moves at a reasonable speed, it just goes to steady
> state. I am not sure whether this is a numerical/physical problem or an
> consequence of the doubly periodic setup.
> >
> > 2 - ice growth shows anomalous growth at the boundaries of the
> partitioning tiles. This results in a distinguishable thickness anomaly.
> Currently I use the same advection scheme than for tracers, a 3-rd order
> flux-limiter (33), and the problem persists when switching to a smaller
> stencil.
> >
> > I am not sure whether the two problems are linked or not. The second one
> looks like a numerical issue but the first one could be due to my
> particular setup.
> > Any idea on what's going on?
> > Thanks!
> >
> > It follows my data and data.seaice files,
> >
> > ############# DATA
> >
> > # Model parameters
> > # Continuous equation parameters
> > &PARM01
> > no_slip_bottom=.FALSE.,
> > eosType='JMD95P',
> > diffKhT=0,
> > diffKzT=0,
> > rotationPeriod=86400.,
> > beta=0,
> > f0=1.4e-4,
> > gravity=9.81,
> > rigidLid=.FALSE.,
> > implicitFreeSurface=.TRUE.,
> > implicitViscosity = .TRUE.,
> > implicitDiffusion = .TRUE.,
> > tempAdvScheme=33,
> > saltAdvScheme=33,
> > viscC2Leith=1.0,
> > staggerTimeStep=.TRUE.,
> > nonHydrostatic=.FALSE.,
> > readBinaryPrec=64,
> > &
> > # Elliptic solver parameters
> > &PARM02
> > cg2dMaxIters=1000,
> > cg2dTargetResidual=1.E-7,
> > &
> > # Time stepping parameters
> > &PARM03
> > endTime=189216000,
> > deltaTmom=240.0,
> > deltaTtracer=240.0,
> > abEps=0.1,
> > pChkptFreq=8640000.0,
> > chkptFreq=1728000.0,
> > dumpFreq=86400.,
> > monitorFreq=864000.,
> > forcing_In_AB = .FALSE.,
> > pickupStrictlyMatch = .TRUE.,
> > &
> >
> > # Gridding parameters
> > &PARM04
> > usingCartesianGrid=.TRUE.,
> > usingSphericalPolarGrid=.FALSE.,
> > delX=400*1000,
> > delY=200*1000,
> > delZ=2, 2, 2, 2, 2, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 10, 10,
> 10, 10, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 30, 50,
> 50, 50, 50, 50,
> > &
> >
> > # Input datasets
> > &PARM05
> > bathyFile='topo.bin',
> > hydrogThetaFile='theta_100_DP.bin',
> > checkIniTemp=.FALSE.,
> > hydrogSaltFile='salinity_100_DP.bin',
> > uVelInitFile='u_100_DP.bin',
> > vVelInitFile='v_100_DP.bin',
> > &
> >
> >
> > ############# DATA.SEAICE
> >
> > &SEAICE_PARM01
> > SEAICEwriteState = .TRUE.,
> > SEAICEuseFlooding = .TRUE.,
> > SEAICE_EPS = 1.E-8,
> > SEAICE_area_floor = 1.E-5,
> > SEAICE_area_reg = 0.15,
> > SEAICE_hice_reg = 0.10,
> > IMAX_TICE = 6,
> > SEAICE_availHeatFrac = 0.8,
> > SEAICEuseDYNAMICS = .TRUE.,
> > HeffFile = 'ice_thick_S.bin',
> > AreaFile = 'ice_fract_S.bin',
> > SEAICEadvScheme = 33,
> > useHB87StressCoupling=.TRUE.,
> > &
> >
> > &SEAICE_PARM03
> > &
> >
> >
> >
> >
> >
> > _______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://mitgcm.org/mailman/listinfo/mitgcm-support
> >
> >
> > _______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://mitgcm.org/mailman/listinfo/mitgcm-support
>
>
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support
>
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Message: 3
Date: Mon, 2 Nov 2015 16:35:43 +0100
From: Martin Losch <Martin.Losch at awi.de>
To: MITgcm Support <mitgcm-support at mitgcm.org>
Subject: Re: [MITgcm-support] The growth rate of sea ice
Message-ID: <B02579E9-253A-40DC-8FB7-D761B5023475 at awi.de>
Content-Type: text/plain; charset="utf-8"
Hi Jianfen,
the code (seaice_growth.F) and the description of the diagnostic SIareaPT ('SIarea preceeding thermodynamic growth/melt?) suggests to me that SIareaPT are indeed the values of area prior to thermodynamics (PT), so you?ll get the thermondynamic growth rate by (SIarea - SIareaPT)/deltaT provided that SIarea and SIareaPT are stored with the same averaging frequency. (analogous for SIheff)
When they are the same, you don?t have any thermodynamic growth.
Martin
> On 29 Oct 2015, at 05:00, weijianfen1988 at 163.com wrote:
>
> Hi,
>
> I just want to output the growth rate of sea ice (concentration or thickness) at each time step. I thought the 'SIareaPT and SIheffPT' are what I need, but they are the same as the real concentration and effective thickness (SIarea and SIheff) after being output and compared. Any ideas?
>
> Thank you very much.
>
> Jianfen
>
> weijianfen1988 at 163.com
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support
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