Changeset 5791 for branches/NERC/dev_r5589_is_oce_cpl/DOC/TexFiles/Chapters/Chap_SBC.tex

Timestamp:

2015-10-13T16:18:04+02:00 (9 years ago)

Author:

mathiot

Message:

ice sheet coupling: add documentation

File:

• branches/NERC/dev_r5589_is_oce_cpl/DOC/TexFiles/Chapters/Chap_SBC.tex (modified) (1 diff)

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

@@ -996 +996 @@
  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 $fields_b = fields_n$.
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