Changeset 5791

2015-10-13T16:18:04+02:00 (5 years ago)

ice sheet coupling: add documentation

2 edited


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

    r5120 r5791  
    996996 at each relevant depth level, added to the horizontal divergence (\textit{hdivn}) in the subroutine \rou{sbc\_isf\_div}  
    997997(called from \mdl{divcur}).  
     999\section{ Ice sheet coupling} 
     1004Ice 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. 
     1005The wetting and drying scheme applied on the restart is very simple and described below for the 6 different configurations: 
     1007\item[Thinning a cell:] 
     1008   T/S/ssh are unchanged and U/V in the top cell are corrected to keep the barotropic transport (bt) constant ($bt_b=bt_n$). 
     1009\item[Enlarge  a cell:] 
     1010   See case "Thinning a cell" 
     1011\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 ($bt_b=bt_n$). 
     1013\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. 
     1015\item[Dry a column:] 
     1016   set mask = 0, T/S = 0, U/V = 0 everywhere in the column and ssh = 0. 
     1017\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. 
     1021This 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. 
     1023As 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 $fields_b = fields_n$. 
    9991025% ================================================================ 
  • branches/NERC/dev_r5589_is_oce_cpl/DOC/TexFiles/Namelist/namrun

    r4147 r5791  
    1515   cn_ocerst_in  = "restart"   !  suffix of ocean restart name (input) 
    1616   cn_ocerst_out = "restart"   !  suffix of ocean restart name (output) 
     17   ln_iscpl    = .false.   !  cavity evolution forcing or coupling to ice sheet model (ln_iscpl = T => namsbc_iscpl) 
    1718   nn_istate   =       0   !  output the initial state (1) or not (0) 
    1819   nn_stock    =    5475   !  frequency of creation of a restart file (modulo referenced to 1) 
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