Changeset 6002


Ignore:
Timestamp:
2015-12-04T16:43:54+01:00 (5 years ago)
Author:
mathiot
Message:

ice sheet cpl: update documentation

Location:
branches/NERC/dev_r5589_is_oce_cpl/DOC/TexFiles
Files:
3 edited

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  • branches/NERC/dev_r5589_is_oce_cpl/DOC/TexFiles/Chapters/Chap_DOM.tex

    r5120 r6002  
    498498Contrary to the horizontal grid, the vertical grid is computed in the code and no  
    499499provision is made for reading it from a file. The only input file is the bathymetry  
    500 (in meters) (\ifile{bathy\_meter})  
     500(in meters) (\ifile{bathy\_meter}).  
    501501\footnote{N.B. in full step $z$-coordinate, a \ifile{bathy\_level} file can replace the  
    502502\ifile{bathy\_meter} file, so that the computation of the number of wet ocean point  
    503503in each water column is by-passed}.  
     504If \np{ln\_isfcav}~=~true, an extra file input file describing the ice shelf draft  
     505(in meters) (\ifile{isf\_draft\_meter}) is needed and all the location where the isf cavity thinnest 
     506 than \np{rn\_isfhmin} meters are grounded (ie masked).  
     507 
    504508After reading the bathymetry, the algorithm for vertical grid definition differs  
    505509between the different options: 
  • branches/NERC/dev_r5589_is_oce_cpl/DOC/TexFiles/Chapters/Chap_SBC.tex

    r5791 r6002  
    10021002\namdisplay{namsbc_iscpl} 
    10031003%-------------------------------------------------------------------------------------------------------- 
    1004 Ice sheet/ocean coupling is done through file exchange at the restart step. NEMO, at each restart step, read the bathymetry and ice shelf draft variable in a netcdf file. If \np{ln\_iscpl = ~true}, the isf draft is assume to be different at each restart step with potentially some new wet/dry cells due to the ice sheet dynamics/thermodynamics. 
    1005 The wetting and drying scheme applied on the restart is very simple and described below for the 6 different configurations: 
     1004Ice sheet/ocean coupling is done through file exchange at the restart step. NEMO, at each restart step,  
     1005read the bathymetry and ice shelf draft variable in a netcdf file.  
     1006If \np{ln\_iscpl = ~true}, the isf draft is assume to be different at each restart step  
     1007with potentially some new wet/dry cells due to the ice sheet dynamics/thermodynamics. 
     1008The wetting and drying scheme applied on the restart is very simple and described below for the 6 different cases: 
    10061009\begin{description} 
    1007 \item[Thinning a cell:] 
     1010\item[Thin a cell down:] 
    10081011   T/S/ssh are unchanged and U/V in the top cell are corrected to keep the barotropic transport (bt) constant ($bt_b=bt_n$). 
    10091012\item[Enlarge  a cell:] 
    1010    See case "Thinning a cell" 
     1013   See case "Thin a cell down" 
    10111014\item[Dry a cell:] 
    1012    mask = 0, T/S=0, U/V = 0, ssh = 0. Furthermore, U/V into the water column are modified to satisfy ($bt_b=bt_n$). 
     1015   mask, T/S, U/V and ssh are set to 0. Furthermore, U/V into the water column are modified to satisfy ($bt_b=bt_n$). 
    10131016\item[Wet a cell:]  
    1014    mask = 1, T/S is extrapolated from neighbours, $ssh_n = ssh_b$ and U/V = 0. If no neighbours along i,j and k, set T/S/U/V = 0 and mask = 0. 
     1017   mask is set to 1, T/S is extrapolated from neighbours, $ssh_n = ssh_b$ and U/V set to 0. If no neighbours along i,j and k, T/S/U/V and mask are set to 0. 
    10151018\item[Dry a column:] 
    1016    set mask = 0, T/S = 0, U/V = 0 everywhere in the column and ssh = 0. 
     1019   mask, T/S, U/V are set to 0 everywhere in the column and ssh set to 0. 
    10171020\item[Wet a column:] 
    1018    set mask to 1, T/S is extrapolated from neighbours, ssh is extrapolated from neighbours, U/V = 0. If no neighbour, T/S/U/V = 0 and set mask to 0. 
     1021   set mask to 1, T/S is extrapolated from neighbours, ssh is extrapolated from neighbours and U/V set to 0. If no neighbour, T/S/U/V and mask set to 0. 
    10191022\end{description} 
    1020  
    1021 This process is able to take into account grounding line and calving front migration. However, this process is not conservative. This could lead to a trend in heat/salt content and volume. In order to remove the trend and keep the conservation level as close to 0 as possible, a simple conservation scheme is available with \np{ln\_hsb = ~true}. The heat/salt/vol. gain/loss is diagnose, as well as the location. Based on what is done on sbcrnf to prescribed a source of heat/salt/vol., the heat/salt/vol. gain/loss is removed/added, over a period of \np{rn\_fiscpl} time step, into the system. So after \np{rn\_fiscpl} time step, all the heat/salt/vol. gain/loss due to extrapolation process is canceled. 
     1023The extrapolation is call \np{nn\_drown} times. It means that if the grounding line retreat by more than \np{nn\_drown} cells between 2 coupling steps, 
     1024 the code will be unable to fill all the new wet cells properly. The default number is set up for the MISOMIP idealised experiments.\\ 
     1025This coupling procedure is able to take into account grounding line and calving front migration. However, it is a non-conservative processe.  
     1026This could lead to a trend in heat/salt content and volume. In order to remove the trend and keep the conservation level as close to 0 as possible, 
     1027 a simple conservation scheme is available with \np{ln\_hsb = ~true}. The heat/salt/vol. gain/loss is diagnose, as well as the location.  
     1028Based on what is done on sbcrnf to prescribed a source of heat/salt/vol., the heat/salt/vol. gain/loss is removed/added, 
     1029 over a period of \np{rn\_fiscpl} time step, into the system.  
     1030So after \np{rn\_fiscpl} time step, all the heat/salt/vol. gain/loss due to extrapolation process is canceled.\\ 
    10221031 
    10231032As the before and now fields are not compatible (modification of the geometry), the restart time step is prescribed to be an euler time step instead of a leap frog and $fields_b = fields_n$. 
  • branches/NERC/dev_r5589_is_oce_cpl/DOC/TexFiles/Namelist/namdom

    r4560 r6002  
    66   nn_msh      =    0      !  create (=1) a mesh file or not (=0) 
    77   rn_hmin     =   -3.     !  min depth of the ocean (>0) or min number of ocean level (<0) 
     8   rn_isfhmin  =    1.00   !  treshold (m) to discriminate grounding ice to floating ice 
    89   rn_e3zps_min=   20.     !  partial step thickness is set larger than the minimum of 
    910   rn_e3zps_rat=    0.1    !  rn_e3zps_min and rn_e3zps_rat*e3t, with 0<rn_e3zps_rat<1 
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