some strange results from ice code ...

Discussion about modeling ice with ROMS

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turuncu
Posts: 128
Joined: Tue Feb 01, 2005 8:21 pm
Location: Istanbul Technical University (ITU)
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some strange results from ice code ...

#1 Unread post by turuncu »

Hi,

I setup ice model for Caspian Sea but i have a problem about that. I started the model from ice free condition using ana_ice.h. The content of the file is,

Code: Select all

     DO j=JstrR,JendR
        DO i=Istr,IendR
           ui(i,j,1) = 0._r8
           uie(i,j,1) = 0._r8
           ui(i,j,2) = ui(i,j,1)
           uie(i,j,2) = uie(i,j,1)
        ENDDO
      ENDDO
      DO j=Jstr,JendR
        DO i=IstrR,IendR
           vi(i,j,1) = 0._r8
           vie(i,j,1) = 0._r8
           vi(i,j,2) = vi(i,j,1)
           vie(i,j,2) = vie(i,j,1)
        ENDDO
      ENDDO
      DO j=JstrR,JendR
        DO i=IstrR,IendR
           ai(i,j,1) = 0._r8
           hi(i,j,1) = 0._r8
           hsn(i,j,1) = 0._r8
           ti(i,j,1) = 0._r8
           sfwat(i,j,1) = 0._r8
           ageice(i,j,1) = 0._r8
           sig11(i,j,1) = 0._r8
           sig22(i,j,1) = 0._r8
           sig12(i,j,1) = 0._r8
           ai(i,j,2) = ai(i,j,1)
           hi(i,j,2) = hi(i,j,1)
           hsn(i,j,2) = hsn(i,j,1)
           ti(i,j,2) = ti(i,j,1)
           sfwat(i,j,2) = sfwat(i,j,1)
           ageice(i,j,2) = ageice(i,j,1)
           sig11(i,j,2) = sig11(i,j,1)
           sig22(i,j,2) = sig22(i,j,1)
           sig12(i,j,2) = sig12(i,j,1)
           tis(i,j) = 0._r8
           s0mk(i,j) = t(i,j,N(ng),1,isalt)
           t0mk(i,j) = t(i,j,N(ng),1,itemp)
           utau_iw(i,j) = 0._r8
           chu_iw(i,j) = 0._r8


so there is no ice at the beginning but when i check the output in the first time step the aice variable is constant with 0.02 value but i expect that it must be zero. Also, after ice forms (in winter) and melt (after mid of spring) the aice is still 0.02 even in the late spring. The same problem also exist in the nice. Please look at the following daily statistics averaged over the sub region,

Code: Select all

date      AVHRR (1990 - degC)         MODEL (1990 - degC)        aice 
dd-mm     NCAS     CCAS    SCAS       NCAS     CCAS    SCAS      NCAS
01-01     4.471    8.707   12.874     4.290    8.653   11.955    0.002
01-02     4.368    8.559   12.638     3.741    8.351   11.546    0.002
01-03     4.306    8.279   12.537     3.376    8.287   11.404    0.002
01-04     4.264    7.893   12.360     3.141    8.303   11.376    0.002
01-05     4.192    7.323   12.162     2.483    8.291   11.383    0.002
01-06     4.092    7.321   11.890     1.394    8.047   11.059    0.002
01-07     3.246    7.352   11.839     0.985    7.857   10.781    0.023
01-08     3.098    7.510   11.850     0.833    7.861   10.620    0.056
01-09     3.369    7.769   11.812     0.736    7.829   10.516    0.073
01-10     3.479    7.975   11.592     0.642    7.756   10.417    0.101
01-11     3.504    8.147   11.389     0.710    7.729   10.319    0.107
01-12     3.461    8.199   11.558     0.873    7.758   10.264    0.107
01-13     2.743    8.151   11.491     1.253    7.780   10.194    0.107
01-14     2.603    8.040   11.307     0.654    7.710   10.144    0.124
01-15     2.539    8.043   11.290     0.537    7.616   10.106    0.202
01-16     2.304    7.917   11.169     0.516    7.665   10.078    0.233
01-17     2.209    7.668   11.014     0.396    7.583   10.023    0.263
01-18     1.276    7.437   10.992     0.494    7.571    9.990    0.273
01-19     1.254    7.136   11.137     0.533    7.564    9.941    0.274
01-20     1.027    6.549   11.119     0.639    7.575    9.920    0.274
01-21     0.955    6.364   11.009     0.698    7.591    9.937    0.274
01-22     0.956    6.284   10.824     0.793    7.592    9.943    0.274
01-23     0.970    6.061   10.758     0.814    7.587    9.970    0.274
01-24     0.571    7.162   10.578     0.812    7.570    9.980    0.274
01-25     0.694    7.521   10.503     0.745    7.488    9.913    0.274
01-26     0.861    7.718   10.636     0.681    7.365    9.808    0.277
01-27     0.952    7.784   10.799     0.762    7.401    9.733    0.280
01-28     0.919    7.648   10.707     0.994    7.379    9.665    0.281
01-29     0.889    7.436   10.543     1.013    7.342    9.655    0.281
01-30     0.661    7.415   10.484     0.944    7.310    9.635    0.281
01-31     0.828    7.447   10.436     0.920    7.239    9.560    0.281
02-01     0.757    7.424   10.297     0.910    7.250    9.566    0.281
02-02     0.428    7.354   10.215     0.880    7.209    9.565    0.282
02-03     0.389    7.300   10.036     0.822    7.162    9.525    0.284
02-04     0.383    7.051    9.934     0.798    7.123    9.456    0.284
02-05     0.476    6.862    9.975     0.829    7.109    9.434    0.282
02-06     0.490    6.695    9.994     0.841    7.091    9.427    0.279
02-07     0.790    6.853    9.943     0.807    7.043    9.385    0.277
02-08     0.858    7.146    9.827     0.771    6.994    9.341    0.275
02-09     0.562    7.199    9.782     0.808    6.990    9.301    0.277
02-10     0.592    7.193    9.767     0.940    7.007    9.300    0.276
02-11     0.590    7.097    9.738     0.957    6.996    9.322    0.274
02-12     0.425    6.837    9.883     0.941    6.966    9.315    0.274
02-13     0.634    6.949   10.268     0.988    7.011    9.315    0.276
02-14     0.703    6.862   10.524     1.125    7.062    9.376    0.274
02-15     0.768    6.806   10.582     1.324    7.115    9.464    0.270
02-16     0.813    6.878   10.529     1.706    7.159    9.540    0.261
02-17     0.798    6.722   10.592     2.019    7.200    9.570    0.249
02-18     0.840    6.335   10.496     2.148    7.210    9.674    0.241
02-19     0.878    6.145   10.407     2.240    7.235    9.716    0.236
02-20     0.913    6.094   10.300     2.340    7.218    9.735    0.233
02-21     0.548    6.152   10.244     2.301    7.163    9.673    0.228
02-22     0.523    6.231    9.563     2.171    7.108    9.583    0.221
02-23     0.546    6.080    9.586     2.087    7.029    9.481    0.219
02-24     0.587    5.885    9.549     2.141    7.005    9.384    0.217
02-25     0.862    6.548    9.505     2.181    7.021    9.376    0.214
02-26     1.647    7.084   10.056     2.337    7.049    9.375    0.207
02-27     1.714    7.125   10.257     2.579    7.081    9.391    0.197
02-28     1.601    7.101   10.417     2.816    7.122    9.452    0.182
03-01     1.498    6.862   10.524     3.034    7.176    9.547    0.157
03-02     1.355    6.925   10.395     3.244    7.265    9.630    0.147
03-03     1.179    6.649    9.901     3.440    7.389    9.822    0.142
03-04     1.521    6.806    9.702     3.674    7.368    9.826    0.135
03-05     1.504    6.868    9.398     3.678    7.348    9.918    0.131
03-06     1.784    7.000    9.022     3.551    7.201    9.718    0.129
03-07     2.071    7.128    9.718     3.567    7.202    9.640    0.124
03-08     2.091    7.175    9.952     3.691    7.242    9.677    0.120
03-09     2.107    7.121   10.381     3.657    7.269    9.770    0.117
03-10     2.505    7.257   10.477     3.819    7.311    9.766    0.113
03-11     2.673    7.345   10.395     4.056    7.362    9.842    0.110
03-12     2.567    7.144   10.018     4.259    7.404    9.946    0.106
03-13     2.530    7.257   10.091     4.499    7.400   10.025    0.100
03-14     2.498    7.327   10.177     4.760    7.509   10.189    0.091
03-15     2.366    7.092    9.914     4.937    7.529   10.164    0.089
03-16     2.370    6.772    9.636     4.514    7.403    9.975    0.085
03-17     2.486    6.983    9.747     4.161    7.297    9.782    0.077
03-18     2.714    7.046    9.768     4.176    7.277    9.603    0.070
03-19     2.865    7.123    9.838     4.199    7.320    9.640    0.068
03-20     2.966    7.224    9.926     4.202    7.282    9.595    0.067
03-21     3.239    7.446   10.032     4.394    7.305    9.545    0.063
03-22     3.196    7.592   10.568     4.839    7.382    9.586    0.058
03-23     3.296    7.799   10.852     5.101    7.435    9.741    0.057
03-24     3.306    7.693   10.578     5.368    7.519    9.873    0.054
03-25     3.830    7.589   10.263     5.796    7.766   10.083    0.050
03-26     4.029    7.877   10.529     6.119    7.778   10.038    0.048
03-27     4.065    8.252   11.009     6.526    8.055   10.272    0.045
03-28     4.063    8.625   11.269     6.912    8.253   10.510    0.044
03-29     3.980    8.723   11.409     7.275    8.602   10.772    0.041
03-30     3.945    8.540   11.320     7.171    8.556   11.066    0.037
03-31     4.442    8.324   11.193     7.097    8.072   10.807    0.033
04-01     5.116    8.166   11.033     7.223    8.046   10.750    0.029
04-02     5.369    7.821   11.038     7.330    8.075   10.957    0.026
04-03     5.420    7.790   10.807     7.488    7.956   10.718    0.024
04-04     5.509    7.742   10.591     7.710    8.013   10.768    0.021
04-05     5.647    7.765   10.635     7.977    8.107   10.972    0.018
04-06     5.704    8.028   11.010     8.261    8.183   11.069    0.016
04-07     6.711    8.332   11.260     8.524    8.223   11.119    0.014
04-08     7.520    9.133   11.655     8.960    8.384   11.269    0.013
04-09     7.659    9.450   12.135     9.295    8.567   11.444    0.011
04-10     7.495   10.047   12.717     9.598    8.534   11.558    0.007
04-11     7.696    9.754   12.965     9.917    8.699   12.045    0.005
04-12     7.735    9.303   12.994    10.143    8.782   12.253    0.005
04-13     7.591    9.054   12.396    10.349    8.890   12.130    0.004
04-14     7.739    9.143   12.475    10.737    9.075   12.230    0.003
04-15     9.006    9.501   12.671    11.163    9.518   12.447    0.003
04-16     9.730    9.969   13.053    11.552    9.432   12.596    0.003
04-17    10.019   10.403   13.251    11.899    9.797   12.758    0.003
04-18    10.299   11.060   13.651    12.077    9.986   12.986    0.002
04-19    10.451   11.412   13.583    12.298    9.813   13.168    0.002
04-20    10.369   11.634   14.142    12.621    9.837   13.107    0.002
04-21    10.345   11.606   14.200    12.822   10.037   13.218    0.002
04-22    11.171   10.957   13.518    12.712    9.843   13.232    0.002
04-23    11.500   10.984   13.531    12.697    9.803   12.737    0.002
04-24    11.898   11.492   13.843    12.868   10.293   12.923    0.002
04-25    12.125   11.983   14.180    13.021   10.583   13.276    0.002
04-26    12.193   11.851   14.769    13.280   10.555   13.726    0.002
04-27    12.216   11.917   15.203    13.708   10.689   14.343    0.002
04-28    12.305   12.040   15.390    14.097   11.198   15.225    0.002
04-29    12.762   11.602   15.160    14.546   11.446   15.408    0.002
04-30    13.276   11.630   14.959    14.735   10.734   14.490    0.002
05-01    13.619   11.841   14.569    14.783   10.797   14.455    0.002
05-02    13.629   11.934   14.640    14.930   11.172   14.823    0.002
05-03    13.448   12.183   15.087    15.097   11.229   15.164    0.002
05-04    12.976   12.374   15.364    15.054   11.516   15.244    0.002
05-05    13.258   12.823   15.606    14.886   11.887   15.574    0.002
05-06    13.765   12.975   15.832    15.191   12.528   16.056    0.002
05-07    14.111   12.765   15.908    15.437   12.059   15.740    0.002
05-08    14.594   13.105   16.493    15.448   11.253   15.249    0.002
05-09    14.828   13.542   17.149    15.714   12.064   15.617    0.002
05-10    15.002   13.605   17.134    16.066   12.828   16.171    0.002
05-11    15.041   13.549   16.999    16.136   12.449   16.235    0.002
05-12    15.067   13.438   16.898    16.182   12.835   16.803    0.002
05-13    15.145   12.991   16.147    16.662   12.624   16.526    0.002
05-14    15.132   12.467   15.993    16.758   11.902   15.852    0.002
05-15    15.155   12.602   16.267    16.467   11.856   15.632    0.002
05-16    15.143   12.644   16.719    16.300   12.016   15.640    0.002
05-17    15.387   12.600   16.677    16.161   12.100   16.094    0.002
05-18    15.594   12.660   17.021    16.257   12.309   16.644    0.002
05-19    16.427   13.107   16.905    16.492   12.891   17.604    0.002
05-20    16.877   13.709   17.444    17.078   13.308   17.211    0.002
05-21    16.924   14.002   17.934    17.533   14.387   17.962    0.002
05-22    16.839   13.899   17.856    17.122   12.993   17.090    0.002
05-23    16.882   13.700   17.005    17.162   13.108   17.140    0.002
05-24    17.032   13.695   17.172    17.230   13.281   17.234    0.002
05-25    17.391   13.489   16.911    17.504   13.490   17.563    0.002
05-26    18.228   15.112   16.953    17.952   13.789   17.606    0.002
05-27    19.149   15.763   18.207    18.426   14.293   17.696    0.002
NCAS: Northern CAS
CCAS: Central CAS
SCAS: Southern CAS


why the ice concentration 0.02 even in the sipping that average water temperature as high as 18 degC. is there any minimum value that is given in the code? also when i look at the nice and vice the data exist in the ice free regions. is it normal?

For your information, i updated the ice code few days ago (20/03/2012).

Regards,

--ufuk

User avatar
kate
Posts: 4088
Joined: Wed Jul 02, 2003 5:29 pm
Location: CFOS/UAF, USA

Re: some strange results from ice code ...

#2 Unread post by kate »

Yes, the ice.in file sets minimum values for aice and hice. You can dial those down to zero if you like. Advection of these zero fields will cause some small noise of non-zero values in the ice-free regions which is annoying - the negative values get whacked. The ice velocities resemble the surface ocean velocities, though perhaps it needs a velocity zeroer where the thickness is zero. Feel free to hack on ice_limit.F, which is a hack from the beginning.

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