Changeset 14525
- Timestamp:
- 2021-02-22T17:18:04+01:00 (3 years ago)
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NEMO/trunk/doc/latex/NEMO/subfiles/chap_SBC.tex
r14375 r14525 975 975 M2, S2, N2, K2, nu2, mu2, 2N2, L2, T2, eps2, lam2, R2, M3, MKS2, MN4, MS4, M4, 976 976 N4, S4, M6, and M8; see file \textit{tide.h90} and \mdl{tide\_mod} for further 977 information and references\footnote{As a legacy option \np{ln_tide_var} can be977 information and references\footnote{As a legacy option \np{ln_tide_var}{ln\_tide\_var} can be 978 978 set to \forcode{0}, in which case the 19 tidal constituents (M2, N2, 2N2, S2, 979 979 K2, K1, O1, Q1, P1, M4, Mf, Mm, Msqm, Mtm, S1, MU2, NU2, L2, and T2; see file … … 1197 1197 1198 1198 \np{ln_isfcav_mlt}{ln\_isfcav\_mlt}\forcode{ = .true.} activates the ocean/ice shelf thermodynamics interactions at the ice shelf/ocean interface. 1199 If \np{ln_isfcav_mlt} \forcode{ = .false.}, thermodynamics interactions are desctivated but the ocean dynamics inside the cavity is still active.1199 If \np{ln_isfcav_mlt}{ln\_isfcav\_mlt}\forcode{ = .false.}, thermodynamics interactions are desctivated but the ocean dynamics inside the cavity is still active. 1200 1200 The logical flag \np{ln_isfcav}{ln\_isfcav} control whether or not the ice shelf cavities are closed. \np{ln_isfcav}{ln\_isfcav} is not defined in the namelist but in the domcfg.nc input file.\\ 1201 1201 1202 1202 3 options are available to represent to ice-shelf/ocean fluxes at the interface: 1203 1203 \begin{description} 1204 \item[\np{cn_isfcav_mlt} \forcode{ = 'spe'}]:1204 \item[\np{cn_isfcav_mlt}{cn\_isfcav\_mlt}\forcode{ = 'spe'}]: 1205 1205 The fresh water flux is specified by a forcing fields \np{sn_isfcav_fwf}{sn\_isfcav\_fwf}. Convention of the input file is: positive toward the ocean (i.e. positive for melting and negative for freezing). 1206 1206 The latent heat fluxes is derived from the fresh water flux. 1207 1207 The heat content flux is derived from the fwf flux assuming a temperature set to the freezing point in the top boundary layer (\np{rn_htbl}{rn\_htbl}) 1208 1208 1209 \item[\np{cn_isfcav_mlt} \forcode{ = 'oasis'}]:1209 \item[\np{cn_isfcav_mlt}{cn\_isfcav\_mlt}\forcode{ = 'oasis'}]: 1210 1210 The \forcode{'oasis'} is a prototype of what could be a method to spread precipitation on Antarctic ice sheet as ice shelf melt inside the cavity when a coupled model Atmosphere/Ocean is used. 1211 1211 It has not been tested and therefore the model will stop if you try to use it. 1212 1212 Actions will be undertake in 2020 to build a comprehensive interface to do so for Greenland, Antarctic and ice shelf (cav), ice shelf (par), icebergs, subglacial runoff and runoff. 1213 1213 1214 \item[\np{cn_isfcav_mlt} \forcode{ = '2eq'}]:1214 \item[\np{cn_isfcav_mlt}{cn\_isfcav\_mlt}\forcode{ = '2eq'}]: 1215 1215 The heat flux and the fresh water flux (negative for melting) resulting from ice shelf melting/freezing are parameterized following \citet{Grosfeld1997}. 1216 1216 This formulation is based on a balance between the vertical diffusive heat flux across the ocean top boundary layer (\autoref{eq:ISOMIP1}) … … 1231 1231 and $\gamma$ the thermal exchange coefficient. 1232 1232 1233 \item[\np{cn_isfcav_mlt} \forcode{ = '3eq'}]:1233 \item[\np{cn_isfcav_mlt}{cn\_isfcav\_mlt}\forcode{ = '3eq'}]: 1234 1234 For realistic studies, the heat and freshwater fluxes are parameterized following \citep{Jenkins2001}. This formulation is based on three equations: 1235 1235 a balance between the vertical diffusive heat flux across the boundary layer … … 1287 1287 If \np{rn_htbl}{rn\_htbl} smaller than top $e_{3}t$, the top boundary layer thickness is set to the top cell thickness.\\ 1288 1288 1289 Each melt formula (\np{cn_isfcav_mlt} \forcode{ = '3eq'} or \np{cn_isfcav_mlt}\forcode{ = '2eq'}) depends on an exchange coeficient ($\Gamma^{T,S}$) between the ocean and the ice.1289 Each melt formula (\np{cn_isfcav_mlt}{cn\_isfcav\_mlt}\forcode{ = '3eq'} or \np{cn_isfcav_mlt}{cn\_isfcav\_mlt}\forcode{ = '2eq'}) depends on an exchange coeficient ($\Gamma^{T,S}$) between the ocean and the ice. 1290 1290 Below, the exchange coeficient $\Gamma^{T}$ and $\Gamma^{S}$ are respectively defined by \np{rn_gammat0}{rn\_gammat0} and \np{rn_gammas0}{rn\_gammas0}. 1291 1291 There are 3 different ways to compute the exchange velocity: 1292 1292 1293 1293 \begin{description} 1294 \item[\np{cn_gammablk} \forcode{='spe'}]:1294 \item[\np{cn_gammablk}{cn\_gammablk}\forcode{='spe'}]: 1295 1295 The salt and heat exchange coefficients are constant and defined by: 1296 1296 \[ … … 1302 1302 This is the recommended formulation for ISOMIP. 1303 1303 1304 \item[\np{cn_gammablk} \forcode{='vel'}]:1304 \item[\np{cn_gammablk}{cn\_gammablk}\forcode{='vel'}]: 1305 1305 The salt and heat exchange coefficients are velocity dependent and defined as 1306 1306 \[ … … 1313 1313 See \citet{jenkins.nicholls.ea_JPO10} for all the details on this formulation. It is the recommended formulation for realistic application and ISOMIP+/MISOMIP configuration. 1314 1314 1315 \item[\np{cn_gammablk} \forcode{'vel\_stab'}]:1315 \item[\np{cn_gammablk}{cn\_gammablk}\forcode{'vel\_stab'}]: 1316 1316 The salt and heat exchange coefficients are velocity and stability dependent and defined as: 1317 1317 \[ … … 1329 1329 \begin{description} 1330 1330 1331 \item[\np{cn_isfpar_mlt} \forcode{ = 'bg03'}]:1331 \item[\np{cn_isfpar_mlt}{cn\_isfpar\_mlt}\forcode{ = 'bg03'}]: 1332 1332 The ice shelf cavities are not represented. 1333 1333 The fwf and heat flux are computed using the \citet{beckmann.goosse_OM03} parameterisation of isf melting. 1334 1334 The fluxes are distributed along the ice shelf edge between the depth of the average grounding line (GL) 1335 1335 (\np{sn_isfpar_zmax}{sn\_isfpar\_zmax}) and the base of the ice shelf along the calving front 1336 (\np{sn_isfpar_zmin}{sn\_isfpar\_zmin}) as in (\np{cn_isfpar_mlt} \forcode{ = 'spe'}).1336 (\np{sn_isfpar_zmin}{sn\_isfpar\_zmin}) as in (\np{cn_isfpar_mlt}{cn\_isfpar\_mlt}\forcode{ = 'spe'}). 1337 1337 The effective melting length (\np{sn_isfpar_Leff}{sn\_isfpar\_Leff}) is read from a file. 1338 1338 This parametrisation has not been tested since a while and based on \citet{Favier2019}, 1339 1339 this parametrisation should probably not be used. 1340 1340 1341 \item[\np{cn_isfpar_mlt} \forcode{ = 'spe'}]:1341 \item[\np{cn_isfpar_mlt}{cn\_isfpar\_mlt}\forcode{ = 'spe'}]: 1342 1342 The ice shelf cavity is not represented. 1343 1343 The fwf (\np{sn_isfpar_fwf}{sn\_isfpar\_fwf}) is prescribed and distributed along the ice shelf edge between … … 1346 1346 The heat flux ($Q_h$) is computed as $Q_h = fwf \times L_f$. 1347 1347 1348 \item[\np{cn_isfpar_mlt} \forcode{ = 'oasis'}]:1348 \item[\np{cn_isfpar_mlt}{cn\_isfpar\_mlt}\forcode{ = 'oasis'}]: 1349 1349 The \forcode{'oasis'} is a prototype of what could be a method to spread precipitation on Antarctic ice sheet as ice shelf melt inside the cavity when a coupled model Atmosphere/Ocean is used. 1350 1350 It has not been tested and therefore the model will stop if you try to use it. … … 1353 1353 \end{description} 1354 1354 1355 \np{cn_isfcav_mlt} \forcode{ = '2eq'}, \np{cn_isfcav_mlt}\forcode{ = '3eq'} and \np{cn_isfpar_mlt}\forcode{ = 'bg03'} compute a melt rate based on1355 \np{cn_isfcav_mlt}{cn\_isfcav\_mlt}\forcode{ = '2eq'}, \np{cn_isfcav_mlt}{cn\_isfcav\_mlt}\forcode{ = '3eq'} and \np{cn_isfpar_mlt}{cn\_isfpar\_mlt}\forcode{ = 'bg03'} compute a melt rate based on 1356 1356 the water mass properties, ocean velocities and depth. 1357 1357 The resulting fluxes are thus highly dependent of the model resolution (horizontal and vertical) and 1358 1358 realism of the water masses onto the shelf.\\ 1359 1359 1360 \np{cn_isfcav_mlt} \forcode{ = 'spe'} and \np{cn_isfpar_mlt}\forcode{ = 'spe'} read the melt rate from a file.1360 \np{cn_isfcav_mlt}{cn\_isfcav\_mlt}\forcode{ = 'spe'} and \np{cn_isfpar_mlt}{cn\_isfpar\_mlt}\forcode{ = 'spe'} read the melt rate from a file. 1361 1361 You have total control of the fwf forcing. 1362 1362 This can be useful if the water masses on the shelf are not realistic or … … 1437 1437 \end{description} 1438 1438 1439 If \np{ln_iscpl} \forcode{ = .true.}, the isf draft is assume to be different at each restart step with1439 If \np{ln_iscpl}{ln\_iscpl}\forcode{ = .true.}, the isf draft is assume to be different at each restart step with 1440 1440 potentially some new wet/dry cells due to the ice sheet dynamics/thermodynamics. 1441 1441 The wetting and drying scheme, applied on the restart, is very simple. The 6 different possible cases for the tracer and ssh are: … … 1482 1482 1483 1483 In order to remove the trend and keep the conservation level as close to 0 as possible, 1484 a simple conservation scheme is available with \np{ln_isfcpl_cons} \forcode{ = .true.}.1484 a simple conservation scheme is available with \np{ln_isfcpl_cons}{ln\_isfcpl\_cons}\forcode{ = .true.}. 1485 1485 The heat/salt/vol. gain/loss are diagnosed, as well as the location. 1486 1486 A correction increment is computed and applied each time step during the model run.
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