Changeset 11537 for NEMO/trunk/doc/latex/NEMO/subfiles/chap_ZDF.tex
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NEMO/trunk/doc/latex/NEMO/subfiles/chap_ZDF.tex
r11435 r11537 39 39 are computed and added to the general trend in the \mdl{dynzdf} and \mdl{trazdf} modules, respectively. 40 40 %These trends can be computed using either a forward time stepping scheme 41 %(namelist parameter \np{ln\_zdfexp}\forcode{ =.true.}) or a backward time stepping scheme42 %(\np{ln\_zdfexp}\forcode{ =.false.}) depending on the magnitude of the mixing coefficients,41 %(namelist parameter \np{ln\_zdfexp}\forcode{=.true.}) or a backward time stepping scheme 42 %(\np{ln\_zdfexp}\forcode{=.false.}) depending on the magnitude of the mixing coefficients, 43 43 %and thus of the formulation used (see \autoref{chap:STP}). 44 44 … … 51 51 % Constant 52 52 % ------------------------------------------------------------------------------------------------------------- 53 \subsection[Constant (\forcode{ln_zdfcst =.true.})]54 {Constant (\protect\np{ln\_zdfcst}\forcode{ =.true.})}53 \subsection[Constant (\forcode{ln_zdfcst=.true.})] 54 {Constant (\protect\np{ln\_zdfcst}\forcode{=.true.})} 55 55 \label{subsec:ZDF_cst} 56 56 … … 74 74 % Richardson Number Dependent 75 75 % ------------------------------------------------------------------------------------------------------------- 76 \subsection[Richardson number dependent (\forcode{ln_zdfric =.true.})]77 {Richardson number dependent (\protect\np{ln\_zdfric}\forcode{ =.true.})}76 \subsection[Richardson number dependent (\forcode{ln_zdfric=.true.})] 77 {Richardson number dependent (\protect\np{ln\_zdfric}\forcode{=.true.})} 78 78 \label{subsec:ZDF_ric} 79 79 … … 83 83 %-------------------------------------------------------------------------------------------------------------- 84 84 85 When \np{ln\_zdfric}\forcode{ =.true.}, a local Richardson number dependent formulation for the vertical momentum and85 When \np{ln\_zdfric}\forcode{=.true.}, a local Richardson number dependent formulation for the vertical momentum and 86 86 tracer eddy coefficients is set through the \nam{zdf\_ric} namelist variables. 87 87 The vertical mixing coefficients are diagnosed from the large scale variables computed by the model. … … 109 109 110 110 A simple mixing-layer model to transfer and dissipate the atmospheric forcings 111 (wind-stress and buoyancy fluxes) can be activated setting the \np{ln\_mldw}\forcode{ =.true.} in the namelist.111 (wind-stress and buoyancy fluxes) can be activated setting the \np{ln\_mldw}\forcode{=.true.} in the namelist. 112 112 113 113 In this case, the local depth of turbulent wind-mixing or "Ekman depth" $h_{e}(x,y,t)$ is evaluated and … … 132 132 % TKE Turbulent Closure Scheme 133 133 % ------------------------------------------------------------------------------------------------------------- 134 \subsection[TKE turbulent closure scheme (\forcode{ln_zdftke =.true.})]135 {TKE turbulent closure scheme (\protect\np{ln\_zdftke}\forcode{ =.true.})}134 \subsection[TKE turbulent closure scheme (\forcode{ln_zdftke=.true.})] 135 {TKE turbulent closure scheme (\protect\np{ln\_zdftke}\forcode{=.true.})} 136 136 \label{subsec:ZDF_tke} 137 137 %--------------------------------------------namzdf_tke-------------------------------------------------- … … 213 213 which is valid in a stable stratified region with constant values of the Brunt-Vais\"{a}l\"{a} frequency. 214 214 The resulting length scale is bounded by the distance to the surface or to the bottom 215 (\np{nn\_mxl}\forcode{ = 0}) or by the local vertical scale factor (\np{nn\_mxl}\forcode{ =1}).215 (\np{nn\_mxl}\forcode{=0}) or by the local vertical scale factor (\np{nn\_mxl}\forcode{=1}). 216 216 \citet{blanke.delecluse_JPO93} notice that this simplification has two major drawbacks: 217 217 it makes no sense for locally unstable stratification and the computation no longer uses all 218 218 the information contained in the vertical density profile. 219 To overcome these drawbacks, \citet{madec.delecluse.ea_NPM98} introduces the \np{nn\_mxl}\forcode{ =2, 3} cases,219 To overcome these drawbacks, \citet{madec.delecluse.ea_NPM98} introduces the \np{nn\_mxl}\forcode{=2, 3} cases, 220 220 which add an extra assumption concerning the vertical gradient of the computed length scale. 221 221 So, the length scales are first evaluated as in \autoref{eq:tke_mxl0_1} and then bounded such that: … … 258 258 where $l^{(k)}$ is computed using \autoref{eq:tke_mxl0_1}, \ie\ $l^{(k)} = \sqrt {2 {\bar e}^{(k)} / {N^2}^{(k)} }$. 259 259 260 In the \np{nn\_mxl}\forcode{ =2} case, the dissipation and mixing length scales take the same value:261 $ l_k= l_\epsilon = \min \left(\ l_{up} \;,\; l_{dwn}\ \right)$, while in the \np{nn\_mxl}\forcode{ =3} case,260 In the \np{nn\_mxl}\forcode{=2} case, the dissipation and mixing length scales take the same value: 261 $ l_k= l_\epsilon = \min \left(\ l_{up} \;,\; l_{dwn}\ \right)$, while in the \np{nn\_mxl}\forcode{=3} case, 262 262 the dissipation and mixing turbulent length scales are give as in \citet{gaspar.gregoris.ea_JGR90}: 263 263 \[ … … 376 376 (\ie\ near-inertial oscillations and ocean swells and waves). 377 377 378 When using this parameterization (\ie\ when \np{nn\_etau}\forcode{ =1}),378 When using this parameterization (\ie\ when \np{nn\_etau}\forcode{=1}), 379 379 the TKE input to the ocean ($S$) imposed by the winds in the form of near-inertial oscillations, 380 380 swell and waves is parameterized by \autoref{eq:ZDF_Esbc} the standard TKE surface boundary condition, … … 389 389 (no penetration if $f_i=1$, \ie\ if the ocean is entirely covered by sea-ice). 390 390 The value of $f_r$, usually a few percents, is specified through \np{rn\_efr} namelist parameter. 391 The vertical mixing length scale, $h_\tau$, can be set as a 10~m uniform value (\np{nn\_etau}\forcode{ =0}) or391 The vertical mixing length scale, $h_\tau$, can be set as a 10~m uniform value (\np{nn\_etau}\forcode{=0}) or 392 392 a latitude dependent value (varying from 0.5~m at the Equator to a maximum value of 30~m at high latitudes 393 (\np{nn\_etau}\forcode{ =1}).394 395 Note that two other option exist, \np{nn\_etau}\forcode{ =2, 3}.393 (\np{nn\_etau}\forcode{=1}). 394 395 Note that two other option exist, \np{nn\_etau}\forcode{=2, 3}. 396 396 They correspond to applying \autoref{eq:ZDF_Ehtau} only at the base of the mixed layer, 397 397 or to using the high frequency part of the stress to evaluate the fraction of TKE that penetrates the ocean. … … 415 415 % GLS Generic Length Scale Scheme 416 416 % ------------------------------------------------------------------------------------------------------------- 417 \subsection[GLS: Generic Length Scale (\forcode{ln_zdfgls =.true.})]418 {GLS: Generic Length Scale (\protect\np{ln\_zdfgls}\forcode{ =.true.})}417 \subsection[GLS: Generic Length Scale (\forcode{ln_zdfgls=.true.})] 418 {GLS: Generic Length Scale (\protect\np{ln\_zdfgls}\forcode{=.true.})} 419 419 \label{subsec:ZDF_gls} 420 420 … … 497 497 \protect\label{tab:GLS} 498 498 Set of predefined GLS parameters, or equivalently predefined turbulence models available with 499 \protect\np{ln\_zdfgls}\forcode{ =.true.} and controlled by the \protect\np{nn\_clos} namelist variable in \protect\nam{zdf\_gls}.499 \protect\np{ln\_zdfgls}\forcode{=.true.} and controlled by the \protect\np{nn\_clos} namelist variable in \protect\nam{zdf\_gls}. 500 500 } 501 501 \end{center} … … 508 508 $C_{\mu}$ and $C_{\mu'}$ are calculated from stability function proposed by \citet{galperin.kantha.ea_JAS88}, 509 509 or by \citet{kantha.clayson_JGR94} or one of the two functions suggested by \citet{canuto.howard.ea_JPO01} 510 (\np{nn\_stab\_func}\forcode{ =0, 3}, resp.).510 (\np{nn\_stab\_func}\forcode{=0, 3}, resp.). 511 511 The value of $C_{0\mu}$ depends on the choice of the stability function. 512 512 … … 525 525 the entrainment depth predicted in stably stratified situations, 526 526 and that its value has to be chosen in accordance with the algebraic model for the turbulent fluxes. 527 The clipping is only activated if \np{ln\_length\_lim}\forcode{ =.true.},527 The clipping is only activated if \np{ln\_length\_lim}\forcode{=.true.}, 528 528 and the $c_{lim}$ is set to the \np{rn\_clim\_galp} value. 529 529 … … 537 537 % OSM OSMOSIS BL Scheme 538 538 % ------------------------------------------------------------------------------------------------------------- 539 \subsection[OSM: OSMosis boundary layer scheme (\forcode{ln_zdfosm =.true.})]540 {OSM: OSMosis boundary layer scheme (\protect\np{ln\_zdfosm}\forcode{ =.true.})}539 \subsection[OSM: OSMosis boundary layer scheme (\forcode{ln_zdfosm=.true.})] 540 {OSM: OSMosis boundary layer scheme (\protect\np{ln\_zdfosm}\forcode{=.true.})} 541 541 \label{subsec:ZDF_osm} 542 542 %--------------------------------------------namzdf_osm--------------------------------------------------------- … … 670 670 % Non-Penetrative Convective Adjustment 671 671 % ------------------------------------------------------------------------------------------------------------- 672 \subsection[Non-penetrative convective adjustment (\forcode{ln_tranpc =.true.})]673 {Non-penetrative convective adjustment (\protect\np{ln\_tranpc}\forcode{ =.true.})}672 \subsection[Non-penetrative convective adjustment (\forcode{ln_tranpc=.true.})] 673 {Non-penetrative convective adjustment (\protect\np{ln\_tranpc}\forcode{=.true.})} 674 674 \label{subsec:ZDF_npc} 675 675 … … 697 697 698 698 Options are defined through the \nam{zdf} namelist variables. 699 The non-penetrative convective adjustment is used when \np{ln\_zdfnpc}\forcode{ =.true.}.699 The non-penetrative convective adjustment is used when \np{ln\_zdfnpc}\forcode{=.true.}. 700 700 It is applied at each \np{nn\_npc} time step and mixes downwards instantaneously the statically unstable portion of 701 701 the water column, but only until the density structure becomes neutrally stable … … 737 737 % Enhanced Vertical Diffusion 738 738 % ------------------------------------------------------------------------------------------------------------- 739 \subsection[Enhanced vertical diffusion (\forcode{ln_zdfevd =.true.})]740 {Enhanced vertical diffusion (\protect\np{ln\_zdfevd}\forcode{ =.true.})}739 \subsection[Enhanced vertical diffusion (\forcode{ln_zdfevd=.true.})] 740 {Enhanced vertical diffusion (\protect\np{ln\_zdfevd}\forcode{=.true.})} 741 741 \label{subsec:ZDF_evd} 742 742 743 743 Options are defined through the \nam{zdf} namelist variables. 744 The enhanced vertical diffusion parameterisation is used when \np{ln\_zdfevd}\forcode{ =.true.}.744 The enhanced vertical diffusion parameterisation is used when \np{ln\_zdfevd}\forcode{=.true.}. 745 745 In this case, the vertical eddy mixing coefficients are assigned very large values 746 746 in regions where the stratification is unstable 747 747 (\ie\ when $N^2$ the Brunt-Vais\"{a}l\"{a} frequency is negative) \citep{lazar_phd97, lazar.madec.ea_JPO99}. 748 This is done either on tracers only (\np{nn\_evdm}\forcode{ =0}) or749 on both momentum and tracers (\np{nn\_evdm}\forcode{ =1}).750 751 In practice, where $N^2\leq 10^{-12}$, $A_T^{vT}$ and $A_T^{vS}$, and if \np{nn\_evdm}\forcode{ =1},748 This is done either on tracers only (\np{nn\_evdm}\forcode{=0}) or 749 on both momentum and tracers (\np{nn\_evdm}\forcode{=1}). 750 751 In practice, where $N^2\leq 10^{-12}$, $A_T^{vT}$ and $A_T^{vS}$, and if \np{nn\_evdm}\forcode{=1}, 752 752 the four neighbouring $A_u^{vm} \;\mbox{and}\;A_v^{vm}$ values also, are set equal to 753 753 the namelist parameter \np{rn\_avevd}. … … 764 764 % Turbulent Closure Scheme 765 765 % ------------------------------------------------------------------------------------------------------------- 766 \subsection{Handling convection with turbulent closure schemes (\forcode{ln_zdf \{tke,gls,osm\} =.true.})}766 \subsection{Handling convection with turbulent closure schemes (\forcode{ln_zdf{tke,gls,osm}=.true.})} 767 767 \label{subsec:ZDF_tcs} 768 768 … … 786 786 The OSMOSIS turbulent closure scheme already includes enhanced vertical diffusion in the case of convection, 787 787 %as governed by the variables $bvsqcon$ and $difcon$ found in \mdl{zdfkpp}, 788 therefore \np{ln\_zdfevd}\forcode{ =.false.} should be used with the OSMOSIS scheme.788 therefore \np{ln\_zdfevd}\forcode{=.false.} should be used with the OSMOSIS scheme. 789 789 % gm% + one word on non local flux with KPP scheme trakpp.F90 module... 790 790 … … 792 792 % Double Diffusion Mixing 793 793 % ================================================================ 794 \section[Double diffusion mixing (\forcode{ln_zdfddm =.true.})]795 {Double diffusion mixing (\protect\np{ln\_zdfddm}\forcode{ =.true.})}794 \section[Double diffusion mixing (\forcode{ln_zdfddm=.true.})] 795 {Double diffusion mixing (\protect\np{ln\_zdfddm}\forcode{=.true.})} 796 796 \label{subsec:ZDF_ddm} 797 797 … … 956 956 % Linear Bottom Friction 957 957 % ------------------------------------------------------------------------------------------------------------- 958 \subsection[Linear top/bottom friction (\forcode{ln_lin =.true.})]959 {Linear top/bottom friction (\protect\np{ln\_lin}\forcode{ =.true.)}}958 \subsection[Linear top/bottom friction (\forcode{ln_lin=.true.})] 959 {Linear top/bottom friction (\protect\np{ln\_lin}\forcode{=.true.)}} 960 960 \label{subsec:ZDF_drg_linear} 961 961 … … 984 984 \] 985 985 When \np{ln\_lin} \forcode{= .true.}, the value of $r$ used is \np{rn\_Uc0}*\np{rn\_Cd0}. 986 Setting \np{ln\_OFF} \forcode{= .true.} (and \forcode{ln_lin =.true.}) is equivalent to setting $r=0$ and leads to a free-slip boundary condition.986 Setting \np{ln\_OFF} \forcode{= .true.} (and \forcode{ln_lin=.true.}) is equivalent to setting $r=0$ and leads to a free-slip boundary condition. 987 987 988 988 These values are assigned in \mdl{zdfdrg}. 989 989 Note that there is support for local enhancement of these values via an externally defined 2D mask array 990 (\np{ln\_boost}\forcode{ =.true.}) given in the \ifile{bfr\_coef} input NetCDF file.990 (\np{ln\_boost}\forcode{=.true.}) given in the \ifile{bfr\_coef} input NetCDF file. 991 991 The mask values should vary from 0 to 1. 992 992 Locations with a non-zero mask value will have the friction coefficient increased by … … 996 996 % Non-Linear Bottom Friction 997 997 % ------------------------------------------------------------------------------------------------------------- 998 \subsection[Non-linear top/bottom friction (\forcode{ln_non_lin =.true.})]999 {Non-linear top/bottom friction (\protect\np{ln\_non\_lin}\forcode{ =.true.})}998 \subsection[Non-linear top/bottom friction (\forcode{ln_non_lin=.true.})] 999 {Non-linear top/bottom friction (\protect\np{ln\_non\_lin}\forcode{=.true.})} 1000 1000 \label{subsec:ZDF_drg_nonlinear} 1001 1001 … … 1025 1025 $C_D$= \np{rn\_Cd0}, and $e_b$ =\np{rn\_bfeb2}. 1026 1026 Note that for applications which consider tides explicitly, a low or even zero value of \np{rn\_bfeb2} is recommended. A local enhancement of $C_D$ is again possible via an externally defined 2D mask array 1027 (\np{ln\_boost}\forcode{ =.true.}).1027 (\np{ln\_boost}\forcode{=.true.}). 1028 1028 This works in the same way as for the linear friction case with non-zero masked locations increased by 1029 1029 $mask\_value$ * \np{rn\_boost} * \np{rn\_Cd0}. … … 1032 1032 % Bottom Friction Log-layer 1033 1033 % ------------------------------------------------------------------------------------------------------------- 1034 \subsection[Log-layer top/bottom friction (\forcode{ln_loglayer =.true.})]1035 {Log-layer top/bottom friction (\protect\np{ln\_loglayer}\forcode{ =.true.})}1034 \subsection[Log-layer top/bottom friction (\forcode{ln_loglayer=.true.})] 1035 {Log-layer top/bottom friction (\protect\np{ln\_loglayer}\forcode{=.true.})} 1036 1036 \label{subsec:ZDF_drg_loglayer} 1037 1037 … … 1053 1053 1054 1054 \noindent The log-layer enhancement can also be applied to the top boundary friction if 1055 under ice-shelf cavities are activated (\np{ln\_isfcav}\forcode{ =.true.}).1055 under ice-shelf cavities are activated (\np{ln\_isfcav}\forcode{=.true.}). 1056 1056 %In this case, the relevant namelist parameters are \np{rn\_tfrz0}, \np{rn\_tfri2} and \np{rn\_tfri2\_max}. 1057 1057 … … 1059 1059 % Explicit bottom Friction 1060 1060 % ------------------------------------------------------------------------------------------------------------- 1061 \subsection{Explicit top/bottom friction (\forcode{ln_drgimp =.false.})}1061 \subsection{Explicit top/bottom friction (\forcode{ln_drgimp=.false.})} 1062 1062 \label{subsec:ZDF_drg_stability} 1063 1063 … … 1120 1120 % Implicit Bottom Friction 1121 1121 % ------------------------------------------------------------------------------------------------------------- 1122 \subsection[Implicit top/bottom friction (\forcode{ln_drgimp =.true.})]1123 {Implicit top/bottom friction (\protect\np{ln\_drgimp}\forcode{ =.true.})}1122 \subsection[Implicit top/bottom friction (\forcode{ln_drgimp=.true.})] 1123 {Implicit top/bottom friction (\protect\np{ln\_drgimp}\forcode{=.true.})} 1124 1124 \label{subsec:ZDF_drg_imp} 1125 1125 … … 1155 1155 \label{subsec:ZDF_drg_ts} 1156 1156 1157 With split-explicit free surface, the sub-stepping of barotropic equations needs the knowledge of top/bottom stresses. An obvious way to satisfy this is to take them as constant over the course of the barotropic integration and equal to the value used to update the baroclinic momentum trend. Provided \np{ln\_drgimp}\forcode{= .false.} and a centred or \textit{leap-frog} like integration of barotropic equations is used (\ie\ \forcode{ln_bt_fw =.false.}, cf \autoref{subsec:DYN_spg_ts}), this does ensure that barotropic and baroclinic dynamics feel the same stresses during one leapfrog time step. However, if \np{ln\_drgimp}\forcode{= .true.}, stresses depend on the \textit{after} value of the velocities which themselves depend on the barotropic iteration result. This cyclic dependency makes difficult obtaining consistent stresses in 2d and 3d dynamics. Part of this mismatch is then removed when setting the final barotropic component of 3d velocities to the time splitting estimate. This last step can be seen as a necessary evil but should be minimized since it interferes with the adjustment to the boundary conditions.1157 With split-explicit free surface, the sub-stepping of barotropic equations needs the knowledge of top/bottom stresses. An obvious way to satisfy this is to take them as constant over the course of the barotropic integration and equal to the value used to update the baroclinic momentum trend. Provided \np{ln\_drgimp}\forcode{= .false.} and a centred or \textit{leap-frog} like integration of barotropic equations is used (\ie\ \forcode{ln_bt_fw=.false.}, cf \autoref{subsec:DYN_spg_ts}), this does ensure that barotropic and baroclinic dynamics feel the same stresses during one leapfrog time step. However, if \np{ln\_drgimp}\forcode{= .true.}, stresses depend on the \textit{after} value of the velocities which themselves depend on the barotropic iteration result. This cyclic dependency makes difficult obtaining consistent stresses in 2d and 3d dynamics. Part of this mismatch is then removed when setting the final barotropic component of 3d velocities to the time splitting estimate. This last step can be seen as a necessary evil but should be minimized since it interferes with the adjustment to the boundary conditions. 1158 1158 1159 1159 The strategy to handle top/bottom stresses with split-explicit free surface in \NEMO\ is as follows: … … 1169 1169 % Internal wave-driven mixing 1170 1170 % ================================================================ 1171 \section[Internal wave-driven mixing (\forcode{ln_zdfiwm =.true.})]1172 {Internal wave-driven mixing (\protect\np{ln\_zdfiwm}\forcode{ =.true.})}1171 \section[Internal wave-driven mixing (\forcode{ln_zdfiwm=.true.})] 1172 {Internal wave-driven mixing (\protect\np{ln\_zdfiwm}\forcode{=.true.})} 1173 1173 \label{subsec:ZDF_tmx_new} 1174 1174 … … 1230 1230 % surface wave-induced mixing 1231 1231 % ================================================================ 1232 \section[Surface wave-induced mixing (\forcode{ln_zdfswm =.true.})]1233 {Surface wave-induced mixing (\protect\np{ln\_zdfswm}\forcode{ =.true.})}1232 \section[Surface wave-induced mixing (\forcode{ln_zdfswm=.true.})] 1233 {Surface wave-induced mixing (\protect\np{ln\_zdfswm}\forcode{=.true.})} 1234 1234 \label{subsec:ZDF_swm} 1235 1235 … … 1254 1254 and diffusivity coefficients. 1255 1255 1256 In order to account for this contribution set: \forcode{ln_zdfswm =.true.},1257 then wave interaction has to be activated through \forcode{ln_wave =.true.},1258 the Stokes Drift can be evaluated by setting \forcode{ln_sdw =.true.}1256 In order to account for this contribution set: \forcode{ln_zdfswm=.true.}, 1257 then wave interaction has to be activated through \forcode{ln_wave=.true.}, 1258 the Stokes Drift can be evaluated by setting \forcode{ln_sdw=.true.} 1259 1259 (see \autoref{subsec:SBC_wave_sdw}) 1260 1260 and the needed wave fields can be provided either in forcing or coupled mode … … 1264 1264 % Adaptive-implicit vertical advection 1265 1265 % ================================================================ 1266 \section[Adaptive-implicit vertical advection (\forcode{ln_zad_Aimp =.true.})]1267 {Adaptive-implicit vertical advection(\protect\np{ln\_zad\_Aimp}\forcode{ =.true.})}1266 \section[Adaptive-implicit vertical advection (\forcode{ln_zad_Aimp=.true.})] 1267 {Adaptive-implicit vertical advection(\protect\np{ln\_zad\_Aimp}\forcode{=.true.})} 1268 1268 \label{subsec:ZDF_aimp} 1269 1269 … … 1283 1283 interest or due to short-lived conditions such that the extra numerical diffusion or 1284 1284 viscosity does not greatly affect the overall solution. With such applications, setting: 1285 \forcode{ln_zad_Aimp =.true.} should allow much longer model timesteps to be used whilst1285 \forcode{ln_zad_Aimp=.true.} should allow much longer model timesteps to be used whilst 1286 1286 retaining the accuracy of the high order explicit schemes over most of the domain. 1287 1287 … … 1407 1407 1408 1408 \noindent which were chosen to provide a slightly more stable and less noisy solution. The 1409 result when using the default value of \forcode{nn_rdt =10.} without adaptive-implicit1409 result when using the default value of \forcode{nn_rdt=10.} without adaptive-implicit 1410 1410 vertical velocity is illustrated in \autoref{fig:zad_Aimp_overflow_frames}. The mass of 1411 1411 cold water, initially sitting on the shelf, moves down the slope and forms a 1412 1412 bottom-trapped, dense plume. Even with these extra physics choices the model is close to 1413 stability limits and attempts with \forcode{nn_rdt =30.} will fail after about 5.5 hours1413 stability limits and attempts with \forcode{nn_rdt=30.} will fail after about 5.5 hours 1414 1414 with excessively high horizontal velocities. This time-scale corresponds with the time the 1415 1415 plume reaches the steepest part of the topography and, although detected as a horizontal … … 1423 1423 significantly altering the solution (although at this extreme the plume is more diffuse 1424 1424 and has not travelled so far). Notably, the solution with and without the scheme is 1425 slightly different even with \forcode{nn_rdt =10.}; suggesting that the base run was1425 slightly different even with \forcode{nn_rdt=10.}; suggesting that the base run was 1426 1426 close enough to instability to trigger the scheme despite completing successfully. 1427 1427 To assist in diagnosing how active the scheme is, in both location and time, the 3D
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