# Changeset 5791

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

ice sheet coupling: add documentation

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

### Legend:

Unmodified
 r5120 at each relevant depth level, added to the horizontal divergence (\textit{hdivn}) in the subroutine \rou{sbc\_isf\_div} (called from \mdl{divcur}). \section{ Ice sheet coupling} \label{SBC_iscpl} %------------------------------------------namsbc_iscpl---------------------------------------------------- \namdisplay{namsbc_iscpl} %-------------------------------------------------------------------------------------------------------- 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. The wetting and drying scheme applied on the restart is very simple and described below for the 6 different configurations: \begin{description} \item[Thinning a cell:] T/S/ssh are unchanged and U/V in the top cell are corrected to keep the barotropic transport (bt) constant ($bt_b=bt_n$). \item[Enlarge  a cell:] See case "Thinning a cell" \item[Dry a cell:] mask = 0, T/S=0, U/V = 0, ssh = 0. Furthermore, U/V into the water column are modified to satisfy ($bt_b=bt_n$). \item[Wet a cell:] 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. \item[Dry a column:] set mask = 0, T/S = 0, U/V = 0 everywhere in the column and ssh = 0. \item[Wet a column:] 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. \end{description} 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. As 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 $fields_b = fields_n$. % % ================================================================