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old new 1 *.aux 2 *.bbl 3 *.blg 4 *.dvi 5 *.fdb* 6 *.fls 7 *.idx 8 *.ilg 9 *.ind 10 *.log 11 *.maf 12 *.mtc* 13 *.out 14 *.pdf 15 *.toc 16 _minted-* 1 figures
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NEMO/branches/2019/fix_vvl_ticket1791/doc/latex/NEMO
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NEMO/branches/2019/fix_vvl_ticket1791/doc/latex/NEMO/subfiles/chap_SBC.tex
r10614 r11422 2 2 3 3 \begin{document} 4 % ================================================================ 5 % Chapter —— Surface Boundary Condition (SBC, ISF, ICB) 6 % ================================================================ 7 \chapter{Surface Boundary Condition (SBC, ISF, ICB) } 4 5 % ================================================================ 6 % Chapter —— Surface Boundary Condition (SBC, SAS, ISF, ICB) 7 % ================================================================ 8 \chapter{Surface Boundary Condition (SBC, SAS, ISF, ICB)} 8 9 \label{chap:SBC} 9 10 \minitoc … … 16 17 %-------------------------------------------------------------------------------------------------------------- 17 18 18 The ocean needs six fields as surface boundary condition: 19 The ocean needs seven fields as surface boundary condition: 20 19 21 \begin{itemize} 20 22 \item … … 26 28 \item 27 29 the surface salt flux associated with freezing/melting of seawater $\left( {\textit{sfx}} \right)$ 30 \item 31 the atmospheric pressure at the ocean surface $\left( p_a \right)$ 28 32 \end{itemize} 29 plus an optional field: 33 34 Four different ways are available to provide the seven fields to the ocean. They are controlled by 35 namelist \ngn{namsbc} variables: 36 30 37 \begin{itemize} 31 \item the atmospheric pressure at the ocean surface $\left( p_a \right)$ 38 \item 39 a bulk formulation (\np{ln\_blk}\forcode{ = .true.} with four possible bulk algorithms), 40 \item 41 a flux formulation (\np{ln\_flx}\forcode{ = .true.}), 42 \item 43 a coupled or mixed forced/coupled formulation (exchanges with a atmospheric model via the OASIS coupler), 44 (\np{ln\_cpl} or \np{ln\_mixcpl}\forcode{ = .true.}), 45 \item 46 a user defined formulation (\np{ln\_usr}\forcode{ = .true.}). 32 47 \end{itemize} 33 48 34 Four different ways to provide the first six fields to the ocean are available which are controlled by35 namelist \ngn{namsbc} variables:36 an analytical formulation (\np{ln\_ana}\forcode{ = .true.}),37 a flux formulation (\np{ln\_flx}\forcode{ = .true.}),38 a bulk formulae formulation (CORE (\np{ln\_blk\_core}\forcode{ = .true.}),39 CLIO (\np{ln\_blk\_clio}\forcode{ = .true.}) bulk formulae) and40 a coupled or mixed forced/coupled formulation (exchanges with a atmospheric model via the OASIS coupler)41 (\np{ln\_cpl} or \np{ln\_mixcpl}\forcode{ = .true.}).42 When used (\ie \np{ln\_apr\_dyn}\forcode{ = .true.}),43 the atmospheric pressure forces both ocean and ice dynamics.44 49 45 50 The frequency at which the forcing fields have to be updated is given by the \np{nn\_fsbc} namelist parameter. 46 When the fields are supplied from data files (flux and bulk formulations), 47 the input fields need not be supplied on the model grid. 48 Instead a file of coordinates and weights can be supplied which maps the data from the supplied grid to 51 52 When the fields are supplied from data files (bulk, flux and mixed formulations), 53 the input fields do not need to be supplied on the model grid. 54 Instead, a file of coordinates and weights can be supplied to map the data from the input fields grid to 49 55 the model points (so called "Interpolation on the Fly", see \autoref{subsec:SBC_iof}). 50 If the Interpolation on the Fly option is used, input data belonging to land points (in the native grid),51 can be masked to avoid spurious results in proximity of the coastsas56 If the "Interpolation on the Fly" option is used, input data belonging to land points (in the native grid) 57 should be masked or filled to avoid spurious results in proximity of the coasts, as 52 58 large sea-land gradients characterize most of the atmospheric variables. 53 59 54 60 In addition, the resulting fields can be further modified using several namelist options. 55 These options control 61 These options control: 62 56 63 \begin{itemize} 57 64 \item 58 65 the rotation of vector components supplied relative to an east-north coordinate system onto 59 the local grid directions in the model; 60 \item 61 the addition of a surface restoring term to observed SST and/or SSS (\np{ln\_ssr}\forcode{ = .true.}); 62 \item 63 the modification of fluxes below ice-covered areas (using observed ice-cover or a sea-ice model) 64 (\np{nn\_ice}\forcode{ = 0..3}); 65 \item 66 the addition of river runoffs as surface freshwater fluxes or lateral inflow (\np{ln\_rnf}\forcode{ = .true.}); 67 \item 68 the addition of isf melting as lateral inflow (parameterisation) or 69 as fluxes applied at the land-ice ocean interface (\np{ln\_isf}) ; 66 the local grid directions in the model, 67 \item 68 the use of a land/sea mask for input fields (\np{nn\_lsm}\forcode{ = .true.}), 69 \item 70 the addition of a surface restoring term to observed SST and/or SSS (\np{ln\_ssr}\forcode{ = .true.}), 71 \item 72 the modification of fluxes below ice-covered areas (using climatological ice-cover or a sea-ice model) 73 (\np{nn\_ice}\forcode{ = 0..3}), 74 \item 75 the addition of river runoffs as surface freshwater fluxes or lateral inflow (\np{ln\_rnf}\forcode{ = .true.}), 76 \item 77 the addition of ice-shelf melting as lateral inflow (parameterisation) or 78 as fluxes applied at the land-ice ocean interface (\np{ln\_isf}\forcode{ = .true.}), 70 79 \item 71 80 the addition of a freshwater flux adjustment in order to avoid a mean sea-level drift 72 (\np{nn\_fwb}\forcode{ = 0..2}); 73 \item 74 the transformation of the solar radiation (if provided as daily mean) into a diurnal cycle 75 (\np{ln\_dm2dc}\forcode{ = .true.}); 76 \item 77 a neutral drag coefficient can be read from an external wave model (\np{ln\_cdgw}\forcode{ = .true.}); 78 \item 79 the Stokes drift rom an external wave model can be accounted (\np{ln\_sdw}\forcode{ = .true.}); 80 \item 81 the Stokes-Coriolis term can be included (\np{ln\_stcor}\forcode{ = .true.}); 82 \item 83 the surface stress felt by the ocean can be modified by surface waves (\np{ln\_tauwoc}\forcode{ = .true.}). 81 (\np{nn\_fwb}\forcode{ = 0..2}), 82 \item 83 the transformation of the solar radiation (if provided as daily mean) into an analytical diurnal cycle 84 (\np{ln\_dm2dc}\forcode{ = .true.}), 85 \item 86 the activation of wave effects from an external wave model (\np{ln\_wave}\forcode{ = .true.}), 87 \item 88 a neutral drag coefficient is read from an external wave model (\np{ln\_cdgw}\forcode{ = .true.}), 89 \item 90 the Stokes drift from an external wave model is accounted for (\np{ln\_sdw}\forcode{ = .true.}), 91 \item 92 the choice of the Stokes drift profile parameterization (\np{nn\_sdrift}\forcode{ = 0..2}), 93 \item 94 the surface stress given to the ocean is modified by surface waves (\np{ln\_tauwoc}\forcode{ = .true.}), 95 \item 96 the surface stress given to the ocean is read from an external wave model (\np{ln\_tauw}\forcode{ = .true.}), 97 \item 98 the Stokes-Coriolis term is included (\np{ln\_stcor}\forcode{ = .true.}), 99 \item 100 the light penetration in the ocean (\np{ln\_traqsr}\forcode{ = .true.} with namelist \ngn{namtra\_qsr}), 101 \item 102 the atmospheric surface pressure gradient effect on ocean and ice dynamics (\np{ln\_apr\_dyn}\forcode{ = .true.} with namelist \ngn{namsbc\_apr}), 103 \item 104 the effect of sea-ice pressure on the ocean (\np{ln\_ice\_embd}\forcode{ = .true.}). 84 105 \end{itemize} 85 106 86 In this chapter, we first discuss where the surface boundary condition appearsin the model equations.87 Then we present the five ways of providing the surface boundary condition,107 In this chapter, we first discuss where the surface boundary conditions appear in the model equations. 108 Then we present the three ways of providing the surface boundary conditions, 88 109 followed by the description of the atmospheric pressure and the river runoff. 89 Next the scheme for interpolation on the fly is described.110 Next, the scheme for interpolation on the fly is described. 90 111 Finally, the different options that further modify the fluxes applied to the ocean are discussed. 91 112 One of these is modification by icebergs (see \autoref{sec:ICB_icebergs}), … … 95 116 96 117 118 97 119 % ================================================================ 98 120 % Surface boundary condition for the ocean 99 121 % ================================================================ 100 122 \section{Surface boundary condition for the ocean} 101 \label{sec:SBC_ general}123 \label{sec:SBC_ocean} 102 124 103 125 The surface ocean stress is the stress exerted by the wind and the sea-ice on the ocean. … … 111 133 The former is the non penetrative part of the heat flux 112 134 (\ie the sum of sensible, latent and long wave heat fluxes plus 113 the heat content of the mass exchange with the atmosphereand sea-ice).135 the heat content of the mass exchange between the ocean and sea-ice). 114 136 It is applied in \mdl{trasbc} module as a surface boundary condition trend of 115 137 the first level temperature time evolution equation 116 (see \autoref{eq:tra_sbc} and \autoref{eq:tra_sbc_lin} in \autoref{subsec:TRA_sbc}). 138 (see \autoref{eq:tra_sbc} and \autoref{eq:tra_sbc_lin} in \autoref{subsec:TRA_sbc}). 117 139 The latter is the penetrative part of the heat flux. 118 It is applied as a 3D trend sof the temperature equation (\mdl{traqsr} module) when140 It is applied as a 3D trend of the temperature equation (\mdl{traqsr} module) when 119 141 \np{ln\_traqsr}\forcode{ = .true.}. 120 142 The way the light penetrates inside the water column is generally a sum of decreasing exponentials … … 124 146 It represents the mass flux exchanged with the atmosphere (evaporation minus precipitation) and 125 147 possibly with the sea-ice and ice shelves (freezing minus melting of ice). 126 It affects boththe ocean in two different ways:127 $(i)$ it changes the volume of the ocean and therefore appears in the sea surface height equation as148 It affects the ocean in two different ways: 149 $(i)$ it changes the volume of the ocean, and therefore appears in the sea surface height equation as %GS: autoref ssh equation to be added 128 150 a volume flux, and 129 151 $(ii)$ it changes the surface temperature and salinity through the heat and salt contents of 130 the mass exchanged with the atmosphere, the sea-ice and the ice shelves.152 the mass exchanged with atmosphere, sea-ice and ice shelves. 131 153 132 154 … … 157 179 the surface currents, temperature and salinity. 158 180 These variables are averaged over \np{nn\_fsbc} time-step (\autoref{tab:ssm}), and 159 it is these averaged fields which are used to computes the surface fluxes at a frequency of \np{nn\_fsbc} time-step.181 these averaged fields are used to compute the surface fluxes at the frequency of \np{nn\_fsbc} time-steps. 160 182 161 183 … … 165 187 \begin{tabular}{|l|l|l|l|} 166 188 \hline 167 Variable description & Model variable & Units & point \\\hline168 i-component of the surface current & ssu\_m & $m.s^{-1}$ & U \\\hline169 j-component of the surface current & ssv\_m & $m.s^{-1}$ & V\\ \hline170 Sea surface temperature & sst\_m & \r{}$K$ & T \\\hline171 Sea surface salinty & sss\_m & $psu$ & T\\ \hline189 Variable description & Model variable & Units & point \\\hline 190 i-component of the surface current & ssu\_m & $m.s^{-1}$ & U \\\hline 191 j-component of the surface current & ssv\_m & $m.s^{-1}$ & V \\ \hline 192 Sea surface temperature & sst\_m & \r{}$K$ & T \\\hline 193 Sea surface salinty & sss\_m & $psu$ & T \\ \hline 172 194 \end{tabular} 173 195 \caption{ 174 196 \protect\label{tab:ssm} 175 197 Ocean variables provided by the ocean to the surface module (SBC). 176 The variable are averaged over nn{\_}fsbc timestep,198 The variable are averaged over \np{nn\_fsbc} time-step, 177 199 \ie the frequency of computation of surface fluxes. 178 200 } … … 184 206 185 207 208 186 209 % ================================================================ 187 210 % Input Data … … 191 214 192 215 A generic interface has been introduced to manage the way input data 193 (2D or 3D fields, like surface forcing or ocean T and S) are specif yin \NEMO.194 This task is a rchieved by \mdl{fldread}.195 The module was designwith four main objectives in mind:216 (2D or 3D fields, like surface forcing or ocean T and S) are specified in \NEMO. 217 This task is achieved by \mdl{fldread}. 218 The module is designed with four main objectives in mind: 196 219 \begin{enumerate} 197 220 \item 198 optionally provide a time interpolation of the input data atmodel time-step, whatever their input frequency is,221 optionally provide a time interpolation of the input data every specified model time-step, whatever their input frequency is, 199 222 and according to the different calendars available in the model. 200 223 \item … … 204 227 \item 205 228 provide a simple user interface and a rather simple developer interface by 206 limiting the number of prerequisite information .207 \end{enumerate} 208 209 As a result s the user haveonly to fill in for each variable a structure in the namelist file to229 limiting the number of prerequisite informations. 230 \end{enumerate} 231 232 As a result, the user has only to fill in for each variable a structure in the namelist file to 210 233 define the input data file and variable names, the frequency of the data (in hours or months), 211 234 whether its is climatological data or not, the period covered by the input file (one year, month, week or day), 212 and three additional parameters for on-the-fly interpolation.235 and three additional parameters for the on-the-fly interpolation. 213 236 When adding a new input variable, the developer has to add the associated structure in the namelist, 214 237 read this information by mirroring the namelist read in \rou{sbc\_blk\_init} for example, … … 220 243 221 244 Note that when an input data is archived on a disc which is accessible directly from the workspace where 222 the code is executed, then the use can set the \np{cn\_dir} to the pathway leading to the data. 223 By default, the data are assumed to have been copied so that cn\_dir='./'. 245 the code is executed, then the user can set the \np{cn\_dir} to the pathway leading to the data. 246 By default, the data are assumed to be in the same directory as the executable, so that cn\_dir='./'. 247 224 248 225 249 % ------------------------------------------------------------------------------------------------------------- 226 250 % Input Data specification (\mdl{fldread}) 227 251 % ------------------------------------------------------------------------------------------------------------- 228 \subsection{Input data specification (\protect\mdl{fldread})} 252 \subsection[Input data specification (\textit{fldread.F90})] 253 {Input data specification (\protect\mdl{fldread})} 229 254 \label{subsec:SBC_fldread} 230 255 … … 237 262 \begin{description} 238 263 \item[File name]: 239 the stem name of the NetCDF file to be open .264 the stem name of the NetCDF file to be opened. 240 265 This stem will be completed automatically by the model, with the addition of a '.nc' at its end and 241 266 by date information and possibly a prefix (when using AGRIF). … … 248 273 \begin{tabular}{|l|c|c|c|} 249 274 \hline 250 & daily or weekLLL & monthly & yearly\\ \hline251 \np{clim}\forcode{ = .false.} & fn\_yYYYYmMMdDD.nc & fn\_yYYYYmMM.nc &fn\_yYYYY.nc \\ \hline252 \np{clim}\forcode{ = .true.} & not possible & fn\_m??.nc & fn\\ \hline275 & daily or weekLL & monthly & yearly \\ \hline 276 \np{clim}\forcode{ = .false.} & fn\_yYYYYmMMdDD.nc & fn\_yYYYYmMM.nc & fn\_yYYYY.nc \\ \hline 277 \np{clim}\forcode{ = .true.} & not possible & fn\_m??.nc & fn \\ \hline 253 278 \end{tabular} 254 279 \end{center} 255 280 \caption{ 256 281 \protect\label{tab:fldread} 257 naming nomenclature for climatological or interannual input file , as a function of the Open/close frequency.282 naming nomenclature for climatological or interannual input file(s), as a function of the open/close frequency. 258 283 The stem name is assumed to be 'fn'. 259 284 For weekly files, the 'LLL' corresponds to the first three letters of the first day of the week … … 262 287 Note that (1) in mpp, if the file is split over each subdomain, the suffix '.nc' is replaced by '\_PPPP.nc', 263 288 where 'PPPP' is the process number coded with 4 digits; 264 (2) when using AGRIF, the prefix '\_N' is added to files, where 'N' 289 (2) when using AGRIF, the prefix '\_N' is added to files, where 'N' is the child grid number. 265 290 } 266 291 \end{table} … … 272 297 Its unit is in hours if it is positive (for example 24 for daily forcing) or in months if negative 273 298 (for example -1 for monthly forcing or -12 for annual forcing). 274 Note that this frequency must reallybe an integer and not a real.275 On some computers, set ing it to '24.' can be interpreted as 240!299 Note that this frequency must REALLY be an integer and not a real. 300 On some computers, setting it to '24.' can be interpreted as 240! 276 301 277 302 \item[Variable name]: … … 284 309 00h00'00'' to 23h59'59". 285 310 If set to 'true', the forcing will have a broken line shape. 286 Records are assumed to be dated the middle of the forcing period.311 Records are assumed to be dated at the middle of the forcing period. 287 312 For example, when using a daily forcing with time interpolation, 288 313 linear interpolation will be performed between mid-day of two consecutive days. … … 291 316 a logical to specify if a input file contains climatological forcing which can be cycle in time, 292 317 or an interannual forcing which will requires additional files if 293 the period covered by the simulation exceed the one of the file.294 See the above thefile naming strategy which impacts the expected name of the file to be opened.318 the period covered by the simulation exceeds the one of the file. 319 See the above file naming strategy which impacts the expected name of the file to be opened. 295 320 296 321 \item[Open/close frequency]: … … 301 326 Files are assumed to contain data from the beginning of the open/close period. 302 327 For example, the first record of a yearly file containing daily data is Jan 1st even if 303 the experiment is not starting at the beginning of the year. 328 the experiment is not starting at the beginning of the year. 304 329 305 330 \item[Others]: … … 313 338 The only tricky point is therefore to specify the date at which we need to do the interpolation and 314 339 the date of the records read in the input files. 315 Following \citet{ Leclair_Madec_OM09}, the date of a time step is set at the middle of the time step.316 For example, for an experiment starting at 0h00'00" with a one 340 Following \citet{leclair.madec_OM09}, the date of a time step is set at the middle of the time step. 341 For example, for an experiment starting at 0h00'00" with a one-hour time-step, 317 342 a time interpolation will be performed at the following time: 0h30'00", 1h30'00", 2h30'00", etc. 318 343 However, for forcing data related to the surface module, 319 344 values are not needed at every time-step but at every \np{nn\_fsbc} time-step. 320 345 For example with \np{nn\_fsbc}\forcode{ = 3}, the surface module will be called at time-steps 1, 4, 7, etc. 321 The date used for the time interpolation is thus redefined to be atthe middle of \np{nn\_fsbc} time-step period.346 The date used for the time interpolation is thus redefined to the middle of \np{nn\_fsbc} time-step period. 322 347 In the previous example, this leads to: 1h30'00", 4h30'00", 7h30'00", etc. \\ 323 348 (2) For code readablility and maintenance issues, we don't take into account the NetCDF input file calendar. … … 325 350 user in the record frequency, the open/close frequency and the type of temporal interpolation. 326 351 For example, the first record of a yearly file containing daily data that will be interpolated in time is assumed to 327 bestart Jan 1st at 12h00'00" and end Dec 31st at 12h00'00". \\352 start Jan 1st at 12h00'00" and end Dec 31st at 12h00'00". \\ 328 353 (3) If a time interpolation is requested, the code will pick up the needed data in the previous (next) file when 329 354 interpolating data with the first (last) record of the open/close period. … … 333 358 If the forcing is climatological, Dec and Jan will be keep-up from the same year. 334 359 However, if the forcing is not climatological, at the end of 335 the open/close period the code will automatically close the current file and open the next one.360 the open/close period, the code will automatically close the current file and open the next one. 336 361 Note that, if the experiment is starting (ending) at the beginning (end) of 337 an open/close period we do accept that the previous (next) file is not existing.362 an open/close period, we do accept that the previous (next) file is not existing. 338 363 In this case, the time interpolation will be performed between two identical values. 339 364 For example, when starting an experiment on Jan 1st of year Y with yearly files and daily data to be interpolated, … … 353 378 Interpolation on the Fly allows the user to supply input files required for the surface forcing on 354 379 grids other than the model grid. 355 To do this he or she must supply, in addition to the source data file, a file of weights to be used to380 To do this, he or she must supply, in addition to the source data file(s), a file of weights to be used to 356 381 interpolate from the data grid to the model grid. 357 382 The original development of this code used the SCRIP package 358 383 (freely available \href{http://climate.lanl.gov/Software/SCRIP}{here} under a copyright agreement). 359 In principle, any package can be used to generate the weights, but the variables in384 In principle, any package such as CDO can be used to generate the weights, but the variables in 360 385 the input weights file must have the same names and meanings as assumed by the model. 361 Two methods are currently available: bilinear and bicubic interpolation .386 Two methods are currently available: bilinear and bicubic interpolations. 362 387 Prior to the interpolation, providing a land/sea mask file, the user can decide to remove land points from 363 388 the input file and substitute the corresponding values with the average of the 8 neighbouring points in … … 365 390 Only "sea points" are considered for the averaging. 366 391 The land/sea mask file must be provided in the structure associated with the input variable. 367 The netcdf land/sea mask variable name must be 'LSM' it must have the same horizontal and vertical dimensions of 368 the associated variable and should be equal to 1 over land and 0 elsewhere. 369 The procedure can be recursively applied setting nn\_lsm > 1 in namsbc namelist. 370 Note that nn\_lsm=0 forces the code to not apply the procedure even if a file for land/sea mask is supplied. 371 392 The netcdf land/sea mask variable name must be 'LSM' and must have the same horizontal and vertical dimensions as 393 the associated variables and should be equal to 1 over land and 0 elsewhere. 394 The procedure can be recursively applied by setting nn\_lsm > 1 in namsbc namelist. 395 Note that nn\_lsm=0 forces the code to not apply the procedure, even if a land/sea mask file is supplied. 396 397 398 % ------------------------------------------------------------------------------------------------------------- 399 % Bilinear interpolation 400 % ------------------------------------------------------------------------------------------------------------- 372 401 \subsubsection{Bilinear interpolation} 373 402 \label{subsec:SBC_iof_bilinear} … … 375 404 The input weights file in this case has two sets of variables: 376 405 src01, src02, src03, src04 and wgt01, wgt02, wgt03, wgt04. 377 The "src" variables correspond to the point in the input grid to which the weight "wgt" is to beapplied.406 The "src" variables correspond to the point in the input grid to which the weight "wgt" is applied. 378 407 Each src value is an integer corresponding to the index of a point in the input grid when 379 408 written as a one dimensional array. … … 391 420 and wgt(1) corresponds to variable "wgt01" for example. 392 421 422 423 % ------------------------------------------------------------------------------------------------------------- 424 % Bicubic interpolation 425 % ------------------------------------------------------------------------------------------------------------- 393 426 \subsubsection{Bicubic interpolation} 394 427 \label{subsec:SBC_iof_bicubic} 395 428 396 Again there are two sets of variables: "src" and "wgt".397 But in this case there are 16 of each.429 Again, there are two sets of variables: "src" and "wgt". 430 But in this case, there are 16 of each. 398 431 The symbolic algorithm used to calculate values on the model grid is now: 399 432 … … 401 434 \begin{split} 402 435 f_{m}(i,j) = f_{m}(i,j) +& \sum_{k=1}^{4} {wgt(k)f(idx(src(k)))} 403 + \sum_{k=5}^{8} {wgt(k)\left.\frac{\partial f}{\partial i}\right| _{idx(src(k))} } \\404 +& \sum_{k=9 }^{12} {wgt(k)\left.\frac{\partial f}{\partial j}\right| _{idx(src(k))} }405 + 436 + \sum_{k=5 }^{8 } {wgt(k)\left.\frac{\partial f}{\partial i}\right| _{idx(src(k))} } \\ 437 +& \sum_{k=9 }^{12} {wgt(k)\left.\frac{\partial f}{\partial j}\right| _{idx(src(k))} } 438 + \sum_{k=13}^{16} {wgt(k)\left.\frac{\partial ^2 f}{\partial i \partial j}\right| _{idx(src(k))} } 406 439 \end{split} 407 440 \] 408 441 The gradients here are taken with respect to the horizontal indices and not distances since 409 the spatial dependency has been absorbed into the weights. 410 442 the spatial dependency has been included into the weights. 443 444 445 % ------------------------------------------------------------------------------------------------------------- 446 % Implementation 447 % ------------------------------------------------------------------------------------------------------------- 411 448 \subsubsection{Implementation} 412 449 \label{subsec:SBC_iof_imp} … … 420 457 inspecting a global attribute stored in the weights input file. 421 458 This attribute must be called "ew\_wrap" and be of integer type. 422 If it is negative, the input non-model grid is assumed not to becyclic.459 If it is negative, the input non-model grid is assumed to be not cyclic. 423 460 If zero or greater, then the value represents the number of columns that overlap. 424 461 $E.g.$ if the input grid has columns at longitudes 0, 1, 2, .... , 359, then ew\_wrap should be set to 0; 425 462 if longitudes are 0.5, 2.5, .... , 358.5, 360.5, 362.5, ew\_wrap should be 2. 426 463 If the model does not find attribute ew\_wrap, then a value of -999 is assumed. 427 In this case the \rou{fld\_read} routine defaults ew\_wrap to value 0 and464 In this case, the \rou{fld\_read} routine defaults ew\_wrap to value 0 and 428 465 therefore the grid is assumed to be cyclic with no overlapping columns. 429 (In fact this only matters when bicubic interpolation is required.)466 (In fact, this only matters when bicubic interpolation is required.) 430 467 Note that no testing is done to check the validity in the model, 431 468 since there is no way of knowing the name used for the longitude variable, … … 444 481 or is a copy of one from the first few columns on the opposite side of the grid (cyclical case). 445 482 483 484 % ------------------------------------------------------------------------------------------------------------- 485 % Limitations 486 % ------------------------------------------------------------------------------------------------------------- 446 487 \subsubsection{Limitations} 447 488 \label{subsec:SBC_iof_lim} … … 449 490 \begin{enumerate} 450 491 \item 451 The case where input data grids are not logically rectangular has not been tested.492 The case where input data grids are not logically rectangular (irregular grid case) has not been tested. 452 493 \item 453 494 This code is not guaranteed to produce positive definite answers from positive definite inputs when … … 470 511 (see the directory NEMOGCM/TOOLS/WEIGHTS). 471 512 513 472 514 % ------------------------------------------------------------------------------------------------------------- 473 515 % Standalone Surface Boundary Condition Scheme 474 516 % ------------------------------------------------------------------------------------------------------------- 475 \subsection{Standalone surface boundary condition scheme }476 \label{subsec:SAS _iof}477 478 %---------------------------------------namsbc_ ana--------------------------------------------------517 \subsection{Standalone surface boundary condition scheme (SAS)} 518 \label{subsec:SAS} 519 520 %---------------------------------------namsbc_sas-------------------------------------------------- 479 521 480 522 \nlst{namsbc_sas} 481 523 %-------------------------------------------------------------------------------------------------------------- 482 524 483 In some circumstances it may be useful to avoid calculating the 3D temperature,525 In some circumstances, it may be useful to avoid calculating the 3D temperature, 484 526 salinity and velocity fields and simply read them in from a previous run or receive them from OASIS. 485 527 For example: … … 496 538 Spinup of the iceberg floats 497 539 \item 498 Ocean/sea-ice simulation with both m ediarunning in parallel (\np{ln\_mixcpl}\forcode{ = .true.})540 Ocean/sea-ice simulation with both models running in parallel (\np{ln\_mixcpl}\forcode{ = .true.}) 499 541 \end{itemize} 500 542 501 The Stand Alone Surface scheme provides this utility.543 The Standalone Surface scheme provides this capacity. 502 544 Its options are defined through the \ngn{namsbc\_sas} namelist variables. 503 545 A new copy of the model has to be compiled with a configuration based on ORCA2\_SAS\_LIM. 504 However no namelist parameters need be changed from the settings of the previous run (except perhaps nn{\_}date0).546 However, no namelist parameters need be changed from the settings of the previous run (except perhaps nn{\_}date0). 505 547 In this configuration, a few routines in the standard model are overriden by new versions. 506 548 Routines replaced are: … … 524 566 so calls to restart functions have been removed. 525 567 This also means that the calendar cannot be controlled by time in a restart file, 526 so the user must make surethat nn{\_}date0 in the model namelist is correct for his or her purposes.568 so the user must check that nn{\_}date0 in the model namelist is correct for his or her purposes. 527 569 \item 528 570 \mdl{stpctl}: … … 543 585 velocity arrays at the surface. 544 586 These filenames are supplied in namelist namsbc{\_}sas. 545 Unfortunately because of limitations with the \mdl{iom} module,587 Unfortunately, because of limitations with the \mdl{iom} module, 546 588 the full 3D fields from the mean files have to be read in and interpolated in time, 547 589 before using just the top level. … … 550 592 551 593 552 % Missing the description of the 2 following variables: 553 % ln_3d_uve = .true. ! specify whether we are supplying a 3D u,v and e3 field 554 % ln_read_frq = .false. ! specify whether we must read frq or not 555 556 557 558 % ================================================================ 559 % Analytical formulation (sbcana module) 560 % ================================================================ 561 \section{Analytical formulation (\protect\mdl{sbcana})} 562 \label{sec:SBC_ana} 563 564 %---------------------------------------namsbc_ana-------------------------------------------------- 565 % 566 %\nlst{namsbc_ana} 567 %-------------------------------------------------------------------------------------------------------------- 568 569 The analytical formulation of the surface boundary condition is the default scheme. 570 In this case, all the six fluxes needed by the ocean are assumed to be uniform in space. 571 They take constant values given in the namelist \ngn{namsbc{\_}ana} by 572 the variables \np{rn\_utau0}, \np{rn\_vtau0}, \np{rn\_qns0}, \np{rn\_qsr0}, and \np{rn\_emp0} 573 ($\textit{emp}=\textit{emp}_S$). 574 The runoff is set to zero. 575 In addition, the wind is allowed to reach its nominal value within a given number of time steps (\np{nn\_tau000}). 576 577 If a user wants to apply a different analytical forcing, 578 the \mdl{sbcana} module can be modified to use another scheme. 579 As an example, the \mdl{sbc\_ana\_gyre} routine provides the analytical forcing for the GYRE configuration 580 (see GYRE configuration manual, in preparation). 594 The user can also choose in the \ngn{namsbc\_sas} namelist to read the mean (nn\_fsbc time-step) fraction of solar net radiation absorbed in the 1st T level using 595 (\np{ln\_flx}\forcode{ = .true.}) and to provide 3D oceanic velocities instead of 2D ones (\np{ln\_flx}\forcode{ = .true.}). In that last case, only the 1st level will be read in. 596 581 597 582 598 … … 584 600 % Flux formulation 585 601 % ================================================================ 586 \section{Flux formulation (\protect\mdl{sbcflx})} 602 \section[Flux formulation (\textit{sbcflx.F90})] 603 {Flux formulation (\protect\mdl{sbcflx})} 587 604 \label{sec:SBC_flx} 588 605 %------------------------------------------namsbc_flx---------------------------------------------------- … … 602 619 603 620 621 604 622 % ================================================================ 605 623 % Bulk formulation 606 624 % ================================================================ 607 \section[Bulk formulation {(\textit{sbcblk\{\_core,\_clio\}.F90})}]608 {Bulk formulation {(\protect\mdl{sbcblk\_core}, \protect\mdl{sbcblk\_clio})}}625 \section[Bulk formulation (\textit{sbcblk.F90})] 626 {Bulk formulation (\protect\mdl{sbcblk})} 609 627 \label{sec:SBC_blk} 610 611 In the bulk formulation, the surface boundary condition fields are computed using bulk formulae and atmospheric fields and ocean (and ice) variables. 628 %---------------------------------------namsbc_blk-------------------------------------------------- 629 630 \nlst{namsbc_blk} 631 %-------------------------------------------------------------------------------------------------------------- 632 633 In the bulk formulation, the surface boundary condition fields are computed with bulk formulae using atmospheric fields 634 and ocean (and sea-ice) variables averaged over \np{nn\_fsbc} time-step. 612 635 613 636 The atmospheric fields used depend on the bulk formulae used. 614 Two bulk formulations are available: 615 the CORE and the CLIO bulk formulea. 637 In forced mode, when a sea-ice model is used, a specific bulk formulation is used. 638 Therefore, different bulk formulae are used for the turbulent fluxes computation 639 over the ocean and over sea-ice surface. 640 For the ocean, four bulk formulations are available thanks to the \href{https://brodeau.github.io/aerobulk/}{Aerobulk} package (\citet{brodeau.barnier.ea_JPO16}): 641 the NCAR (formerly named CORE), COARE 3.0, COARE 3.5 and ECMWF bulk formulae. 616 642 The choice is made by setting to true one of the following namelist variable: 617 \np{ln\_core} or \np{ln\_clio}. 618 619 Note: 620 in forced mode, when a sea-ice model is used, a bulk formulation (CLIO or CORE) have to be used. 621 Therefore the two bulk (CLIO and CORE) formulea include the computation of the fluxes over 622 both an ocean and an ice surface. 623 624 % ------------------------------------------------------------------------------------------------------------- 625 % CORE Bulk formulea 626 % ------------------------------------------------------------------------------------------------------------- 627 \subsection{CORE formulea (\protect\mdl{sbcblk\_core}, \protect\np{ln\_core}\forcode{ = .true.})} 628 \label{subsec:SBC_blk_core} 629 %------------------------------------------namsbc_core---------------------------------------------------- 630 % 631 %\nlst{namsbc_core} 632 %------------------------------------------------------------------------------------------------------------- 633 634 The CORE bulk formulae have been developed by \citet{Large_Yeager_Rep04}. 635 They have been designed to handle the CORE forcing, a mixture of NCEP reanalysis and satellite data. 636 They use an inertial dissipative method to compute the turbulent transfer coefficients 637 (momentum, sensible heat and evaporation) from the 10 metre wind speed, air temperature and specific humidity. 638 This \citet{Large_Yeager_Rep04} dataset is available through 639 the \href{http://nomads.gfdl.noaa.gov/nomads/forms/mom4/CORE.html}{GFDL web site}. 640 641 Note that substituting ERA40 to NCEP reanalysis fields does not require changes in the bulk formulea themself. 642 This is the so-called DRAKKAR Forcing Set (DFS) \citep{Brodeau_al_OM09}. 643 644 Options are defined through the \ngn{namsbc\_core} namelist variables. 645 The required 8 input fields are: 643 \np{ln\_NCAR}, \np{ln\_COARE\_3p0}, \np{ln\_COARE\_3p5} and \np{ln\_ECMWF}. 644 For sea-ice, three possibilities can be selected: 645 a constant transfer coefficient (1.4e-3; default value), \citet{lupkes.gryanik.ea_JGR12} (\np{ln\_Cd\_L12}), and \citet{lupkes.gryanik_JGR15} (\np{ln\_Cd\_L15}) parameterizations 646 647 Common options are defined through the \ngn{namsbc\_blk} namelist variables. 648 The required 9 input fields are: 646 649 647 650 %--------------------------------------------------TABLE-------------------------------------------------- 648 651 \begin{table}[htbp] 649 \label{tab: CORE}652 \label{tab:BULK} 650 653 \begin{center} 651 654 \begin{tabular}{|l|c|c|c|} 652 655 \hline 653 Variable desciption & Model variable & Units & point \\ \hline 654 i-component of the 10m air velocity & utau & $m.s^{-1}$ & T \\ \hline 655 j-component of the 10m air velocity & vtau & $m.s^{-1}$ & T \\ \hline 656 10m air temperature & tair & \r{}$K$ & T \\ \hline 657 Specific humidity & humi & \% & T \\ \hline 658 Incoming long wave radiation & qlw & $W.m^{-2}$ & T \\ \hline 659 Incoming short wave radiation & qsr & $W.m^{-2}$ & T \\ \hline 660 Total precipitation (liquid + solid) & precip & $Kg.m^{-2}.s^{-1}$ & T \\ \hline 661 Solid precipitation & snow & $Kg.m^{-2}.s^{-1}$ & T \\ \hline 656 Variable description & Model variable & Units & point \\ \hline 657 i-component of the 10m air velocity & utau & $m.s^{-1}$ & T \\ \hline 658 j-component of the 10m air velocity & vtau & $m.s^{-1}$ & T \\ \hline 659 10m air temperature & tair & \r{}$K$ & T \\ \hline 660 Specific humidity & humi & \% & T \\ \hline 661 Incoming long wave radiation & qlw & $W.m^{-2}$ & T \\ \hline 662 Incoming short wave radiation & qsr & $W.m^{-2}$ & T \\ \hline 663 Total precipitation (liquid + solid) & precip & $Kg.m^{-2}.s^{-1}$ & T \\ \hline 664 Solid precipitation & snow & $Kg.m^{-2}.s^{-1}$ & T \\ \hline 665 Mean sea-level pressure & slp & $hPa$ & T \\ \hline 662 666 \end{tabular} 663 667 \end{center} … … 678 682 \np{rn\_zu}: is the height of wind measurements (m) 679 683 680 Three multiplicative factors are available s:681 \np{rn\_pfac} and \np{rn\_efac} allow sto adjust (if necessary) the global freshwater budget by684 Three multiplicative factors are available: 685 \np{rn\_pfac} and \np{rn\_efac} allow to adjust (if necessary) the global freshwater budget by 682 686 increasing/reducing the precipitations (total and snow) and or evaporation, respectively. 683 687 The third one,\np{rn\_vfac}, control to which extend the ice/ocean velocities are taken into account in 684 688 the calculation of surface wind stress. 685 Its range should be between zero and one, and it is recommended to set it to 0. 686 687 % ------------------------------------------------------------------------------------------------------------- 688 % CLIO Bulk formulea 689 % ------------------------------------------------------------------------------------------------------------- 690 \subsection{CLIO formulea (\protect\mdl{sbcblk\_clio}, \protect\np{ln\_clio}\forcode{ = .true.})} 691 \label{subsec:SBC_blk_clio} 692 %------------------------------------------namsbc_clio---------------------------------------------------- 693 % 694 %\nlst{namsbc_clio} 695 %------------------------------------------------------------------------------------------------------------- 696 697 The CLIO bulk formulae were developed several years ago for the Louvain-la-neuve coupled ice-ocean model 698 (CLIO, \cite{Goosse_al_JGR99}). 699 They are simpler bulk formulae. 700 They assume the stress to be known and compute the radiative fluxes from a climatological cloud cover. 701 702 Options are defined through the \ngn{namsbc\_clio} namelist variables. 703 The required 7 input fields are: 704 705 %--------------------------------------------------TABLE-------------------------------------------------- 706 \begin{table}[htbp] 707 \label{tab:CLIO} 708 \begin{center} 709 \begin{tabular}{|l|l|l|l|} 710 \hline 711 Variable desciption & Model variable & Units & point \\ \hline 712 i-component of the ocean stress & utau & $N.m^{-2}$ & U \\ \hline 713 j-component of the ocean stress & vtau & $N.m^{-2}$ & V \\ \hline 714 Wind speed module & vatm & $m.s^{-1}$ & T \\ \hline 715 10m air temperature & tair & \r{}$K$ & T \\ \hline 716 Specific humidity & humi & \% & T \\ \hline 717 Cloud cover & & \% & T \\ \hline 718 Total precipitation (liquid + solid) & precip & $Kg.m^{-2}.s^{-1}$ & T \\ \hline 719 Solid precipitation & snow & $Kg.m^{-2}.s^{-1}$ & T \\ \hline 720 \end{tabular} 721 \end{center} 722 \end{table} 723 %-------------------------------------------------------------------------------------------------------------- 689 Its range must be between zero and one, and it is recommended to set it to 0 at low-resolution (ORCA2 configuration). 724 690 725 691 As for the flux formulation, information about the input data required by the model is provided in 726 the namsbc\_blk\_core or namsbc\_blk\_clio namelist (see \autoref{subsec:SBC_fldread}). 692 the namsbc\_blk namelist (see \autoref{subsec:SBC_fldread}). 693 694 695 % ------------------------------------------------------------------------------------------------------------- 696 % Ocean-Atmosphere Bulk formulae 697 % ------------------------------------------------------------------------------------------------------------- 698 \subsection{Ocean-Atmosphere Bulk formulae} 699 %\subsection[Ocean-Atmosphere Bulk formulae (\textit{sbcblk_algo\{\_ncar,\_coare,\_coare3p5,\_ecmwf}.F90})] 700 \label{subsec:SBC_blk_ocean} 701 702 Four different bulk algorithms are available to compute surface turbulent momentum and heat fluxes over the ocean. 703 COARE 3.0, COARE 3.5 and ECMWF schemes mainly differ by their roughness lenghts computation and consequently 704 their neutral transfer coefficients relationships with neutral wind. 705 \begin{itemize} 706 \item 707 NCAR (\np{ln\_NCAR}\forcode{ = .true.}): 708 The NCAR bulk formulae have been developed by \citet{large.yeager_rpt04}. 709 They have been designed to handle the NCAR forcing, a mixture of NCEP reanalysis and satellite data. 710 They use an inertial dissipative method to compute the turbulent transfer coefficients 711 (momentum, sensible heat and evaporation) from the 10m wind speed, air temperature and specific humidity. 712 This \citet{large.yeager_rpt04} dataset is available through 713 the \href{http://nomads.gfdl.noaa.gov/nomads/forms/mom4/NCAR.html}{GFDL web site}. 714 Note that substituting ERA40 to NCEP reanalysis fields does not require changes in the bulk formulea themself. 715 This is the so-called DRAKKAR Forcing Set (DFS) \citep{brodeau.barnier.ea_OM10}. 716 \item 717 COARE 3.0 (\np{ln\_COARE\_3p0}\forcode{ = .true.}): 718 See \citet{fairall.bradley.ea_JC03} for more details 719 \item 720 COARE 3.5 (\np{ln\_COARE\_3p5}\forcode{ = .true.}): 721 See \citet{edson.jampana.ea_JPO13} for more details 722 \item 723 ECMWF (\np{ln\_ECMWF}\forcode{ = .true.}): 724 Based on \href{https://www.ecmwf.int/node/9221}{IFS (Cy31)} implementation and documentation. 725 Surface roughness lengths needed for the Obukhov length are computed following \citet{beljaars_QJRMS95}. 726 \end{itemize} 727 728 729 % ------------------------------------------------------------------------------------------------------------- 730 % Ice-Atmosphere Bulk formulae 731 % ------------------------------------------------------------------------------------------------------------- 732 \subsection{ Ice-Atmosphere Bulk formulae } 733 \label{subsec:SBC_blk_ice} 734 735 Surface turbulent fluxes between sea-ice and the atmosphere can be computed in three different ways: 736 737 \begin{itemize} 738 \item 739 Constant value (\np{constant\ value}\forcode{ Cd_ice = 1.4e-3 }): 740 default constant value used for momentum and heat neutral transfer coefficients 741 \item 742 \citet{lupkes.gryanik.ea_JGR12} (\np{ln\_Cd\_L12}\forcode{ = .true.}): 743 This scheme adds a dependency on edges at leads, melt ponds and flows 744 of the constant neutral air-ice drag. After some approximations, 745 this can be resumed to a dependency on ice concentration (A). 746 This drag coefficient has a parabolic shape (as a function of ice concentration) 747 starting at 1.5e-3 for A=0, reaching 1.97e-3 for A=0.5 and going down 1.4e-3 for A=1. 748 It is theoretically applicable to all ice conditions (not only MIZ). 749 \item 750 \citet{lupkes.gryanik_JGR15} (\np{ln\_Cd\_L15}\forcode{ = .true.}): 751 Alternative turbulent transfer coefficients formulation between sea-ice 752 and atmosphere with distinct momentum and heat coefficients depending 753 on sea-ice concentration and atmospheric stability (no melt-ponds effect for now). 754 The parameterization is adapted from ECHAM6 atmospheric model. 755 Compared to Lupkes2012 scheme, it considers specific skin and form drags 756 to compute neutral transfer coefficients for both heat and momentum fluxes. 757 Atmospheric stability effect on transfer coefficient is also taken into account. 758 \end{itemize} 759 760 727 761 728 762 % ================================================================ 729 763 % Coupled formulation 730 764 % ================================================================ 731 \section{Coupled formulation (\protect\mdl{sbccpl})} 765 \section[Coupled formulation (\textit{sbccpl.F90})] 766 {Coupled formulation (\protect\mdl{sbccpl})} 732 767 \label{sec:SBC_cpl} 733 768 %------------------------------------------namsbc_cpl---------------------------------------------------- … … 737 772 738 773 In the coupled formulation of the surface boundary condition, 739 the fluxes are provided by the OASIS coupler at a frequency which is defined in the OASIS coupler ,774 the fluxes are provided by the OASIS coupler at a frequency which is defined in the OASIS coupler namelist, 740 775 while sea and ice surface temperature, ocean and ice albedo, and ocean currents are sent to 741 776 the atmospheric component. 742 777 743 778 A generalised coupled interface has been developed. 744 It is currently interfaced with OASIS-3-MCT (\key{oasis3}). 779 It is currently interfaced with OASIS-3-MCT versions 1 to 4 (\key{oasis3}). 780 An additional specific CPP key (\key{oa3mct\_v1v2}) is needed for OASIS-3-MCT versions 1 and 2. 745 781 It has been successfully used to interface \NEMO to most of the European atmospheric GCM 746 782 (ARPEGE, ECHAM, ECMWF, HadAM, HadGAM, LMDz), as well as to \href{http://wrf-model.org/}{WRF} 747 783 (Weather Research and Forecasting Model). 748 784 749 Note that in addition to the setting of \np{ln\_cpl} to true, the \key{coupled} have to be defined. 750 The CPP key is mainly used in sea-ice to ensure that the atmospheric fluxes are actually received by 751 the ice-ocean system (no calculation of ice sublimation in coupled mode). 752 When PISCES biogeochemical model (\key{top} and \key{pisces}) is also used in the coupled system, 753 the whole carbon cycle is computed by defining \key{cpl\_carbon\_cycle}. 785 When PISCES biogeochemical model (\key{top}) is also used in the coupled system, 786 the whole carbon cycle is computed. 754 787 In this case, CO$_2$ fluxes will be exchanged between the atmosphere and the ice-ocean system 755 788 (and need to be activated in \ngn{namsbc{\_}cpl} ). … … 757 790 The namelist above allows control of various aspects of the coupling fields (particularly for vectors) and 758 791 now allows for any coupling fields to have multiple sea ice categories (as required by LIM3 and CICE). 759 When indicating a multi-category coupling field in namsbc{\_}cplthe number of categories will be determined by792 When indicating a multi-category coupling field in \ngn{namsbc{\_}cpl}, the number of categories will be determined by 760 793 the number used in the sea ice model. 761 In some limited cases it may be possible to specify single category coupling fields even when794 In some limited cases, it may be possible to specify single category coupling fields even when 762 795 the sea ice model is running with multiple categories - 763 in this case the user should examine the code to be sure the assumptions made are satisfactory. 764 In cases where this is definitely not possible the model should abort with an error message. 765 The new code has been tested using ECHAM with LIM2, and HadGAM3 with CICE but 766 although it will compile with \key{lim3} additional minor code changes may be required to run using LIM3. 796 in this case, the user should examine the code to be sure the assumptions made are satisfactory. 797 In cases where this is definitely not possible, the model should abort with an error message. 798 767 799 768 800 … … 770 802 % Atmospheric pressure 771 803 % ================================================================ 772 \section{Atmospheric pressure (\protect\mdl{sbcapr})} 804 \section[Atmospheric pressure (\textit{sbcapr.F90})] 805 {Atmospheric pressure (\protect\mdl{sbcapr})} 773 806 \label{sec:SBC_apr} 774 807 %------------------------------------------namsbc_apr---------------------------------------------------- … … 778 811 779 812 The optional atmospheric pressure can be used to force ocean and ice dynamics 780 (\np{ln\_apr\_dyn}\forcode{ = .true.}, \ textit{\ngn{namsbc}} namelist).781 The input atmospheric forcing defined via \np{sn\_apr} structure (\ textit{namsbc\_apr} namelist)813 (\np{ln\_apr\_dyn}\forcode{ = .true.}, \ngn{namsbc} namelist). 814 The input atmospheric forcing defined via \np{sn\_apr} structure (\ngn{namsbc\_apr} namelist) 782 815 can be interpolated in time to the model time step, and even in space when the interpolation on-the-fly is used. 783 816 When used to force the dynamics, the atmospheric pressure is further transformed into … … 789 822 where $P_{atm}$ is the atmospheric pressure and $P_o$ a reference atmospheric pressure. 790 823 A value of $101,000~N/m^2$ is used unless \np{ln\_ref\_apr} is set to true. 791 In this case $P_o$ is set to the value of $P_{atm}$ averaged over the ocean domain,792 \ie the mean value of $\eta_{ib}$ is kept to zero at all time step .824 In this case, $P_o$ is set to the value of $P_{atm}$ averaged over the ocean domain, 825 \ie the mean value of $\eta_{ib}$ is kept to zero at all time steps. 793 826 794 827 The gradient of $\eta_{ib}$ is added to the RHS of the ocean momentum equation (see \mdl{dynspg} for the ocean). 795 828 For sea-ice, the sea surface height, $\eta_m$, which is provided to the sea ice model is set to $\eta - \eta_{ib}$ 796 829 (see \mdl{sbcssr} module). 797 $\eta_{ib}$ can be setin the output.830 $\eta_{ib}$ can be written in the output. 798 831 This can simplify altimetry data and model comparison as 799 832 inverse barometer sea surface height is usually removed from these date prior to their distribution. … … 803 836 \np{ln\_apr\_obc} might be set to true. 804 837 838 839 805 840 % ================================================================ 806 841 % Surface Tides Forcing 807 842 % ================================================================ 808 \section{Surface tides (\protect\mdl{sbctide})} 843 \section[Surface tides (\textit{sbctide.F90})] 844 {Surface tides (\protect\mdl{sbctide})} 809 845 \label{sec:SBC_tide} 810 846 … … 819 855 \[ 820 856 % \label{eq:PE_dyn_tides} 821 \frac{\partial {\ rm {\bf U}}_h }{\partial t}= ...857 \frac{\partial {\mathrm {\mathbf U}}_h }{\partial t}= ... 822 858 +g\nabla (\Pi_{eq} + \Pi_{sal}) 823 859 \] … … 827 863 The equilibrium tidal forcing is expressed as a sum over a subset of 828 864 constituents chosen from the set of available tidal constituents 829 defined in file \ rou{SBC/tide.h90} (this comprises the tidal865 defined in file \textit{SBC/tide.h90} (this comprises the tidal 830 866 constituents \textit{M2, N2, 2N2, S2, K2, K1, O1, Q1, P1, M4, Mf, Mm, 831 867 Msqm, Mtm, S1, MU2, NU2, L2}, and \textit{T2}). Individual … … 839 875 840 876 The SAL term should in principle be computed online as it depends on 841 the model tidal prediction itself (see \citet{ Arbic2004} for a877 the model tidal prediction itself (see \citet{arbic.garner.ea_DSR04} for a 842 878 discussion about the practical implementation of this term). 843 879 Nevertheless, the complex calculations involved would make this 844 computationally too expensive. 880 computationally too expensive. Here, two options are available: 845 881 $\Pi_{sal}$ generated by an external model can be read in 846 882 (\np{ln\_read\_load=.true.}), or a ``scalar approximation'' can be … … 854 890 \forcode{.false.} removes the SAL contribution. 855 891 892 893 856 894 % ================================================================ 857 895 % River runoffs 858 896 % ================================================================ 859 \section{River runoffs (\protect\mdl{sbcrnf})} 897 \section[River runoffs (\textit{sbcrnf.F90})] 898 {River runoffs (\protect\mdl{sbcrnf})} 860 899 \label{sec:SBC_rnf} 861 900 %------------------------------------------namsbc_rnf---------------------------------------------------- … … 871 910 %coastal modelling and becomes more and more often open ocean and climate modelling 872 911 %\footnote{At least a top cells thickness of 1~meter and a 3 hours forcing frequency are 873 %required to properly represent the diurnal cycle \citep{ Bernie_al_JC05}. see also \autoref{fig:SBC_dcy}.}.912 %required to properly represent the diurnal cycle \citep{bernie.woolnough.ea_JC05}. see also \autoref{fig:SBC_dcy}.}. 874 913 875 914 … … 892 931 \footnote{ 893 932 At least a top cells thickness of 1~meter and a 3 hours forcing frequency are required to 894 properly represent the diurnal cycle \citep{ Bernie_al_JC05}.933 properly represent the diurnal cycle \citep{bernie.woolnough.ea_JC05}. 895 934 see also \autoref{fig:SBC_dcy}.}. 896 935 … … 935 974 As such the volume of water does not change, but the water is diluted. 936 975 937 For the non-linear free surface case (\key{vvl}), no flux is allowed through the surface.976 For the non-linear free surface case, no flux is allowed through the surface. 938 977 Instead in the surface box (as well as water moving up from the boxes below) a volume of runoff water is added with 939 978 no corresponding heat and salt addition and so as happens in the lower boxes there is a dilution effect. … … 978 1017 %To do this we need to treat evaporation/precipitation fluxes and river runoff differently in the tra_sbc module. We decided to separate them throughout the code, so that the variable emp represented solely evaporation minus precipitation fluxes, and a new 2d variable rnf was added which represents the volume flux of river runoff (in kg/m2s to remain consistent with emp). This meant many uses of emp and emps needed to be changed, a list of all modules which use emp or emps and the changes made are below: 979 1018 980 %} 1019 1020 981 1021 % ================================================================ 982 1022 % Ice shelf melting 983 1023 % ================================================================ 984 \section{Ice shelf melting (\protect\mdl{sbcisf})} 1024 \section[Ice shelf melting (\textit{sbcisf.F90})] 1025 {Ice shelf melting (\protect\mdl{sbcisf})} 985 1026 \label{sec:SBC_isf} 986 1027 %------------------------------------------namsbc_isf---------------------------------------------------- … … 988 1029 \nlst{namsbc_isf} 989 1030 %-------------------------------------------------------------------------------------------------------- 1031 990 1032 The namelist variable in \ngn{namsbc}, \np{nn\_isf}, controls the ice shelf representation. 991 Description and result of sensitivity test to \np{nn\_isf} are presented in \citet{ Mathiot2017}.1033 Description and result of sensitivity test to \np{nn\_isf} are presented in \citet{mathiot.jenkins.ea_GMD17}. 992 1034 The different options are illustrated in \autoref{fig:SBC_isf}. 993 1035 994 1036 \begin{description} 995 \item[\np{nn\_isf}\forcode{ = 1}]: 1037 1038 \item[\np{nn\_isf}\forcode{ = 1}]: 996 1039 The ice shelf cavity is represented (\np{ln\_isfcav}\forcode{ = .true.} needed). 997 1040 The fwf and heat flux are depending of the local water properties. 1041 998 1042 Two different bulk formulae are available: 999 1043 … … 1001 1045 \item[\np{nn\_isfblk}\forcode{ = 1}]: 1002 1046 The melt rate is based on a balance between the upward ocean heat flux and 1003 the latent heat flux at the ice shelf base. A complete description is available in \citet{ Hunter2006}.1047 the latent heat flux at the ice shelf base. A complete description is available in \citet{hunter_rpt06}. 1004 1048 \item[\np{nn\_isfblk}\forcode{ = 2}]: 1005 1049 The melt rate and the heat flux are based on a 3 equations formulation 1006 1050 (a heat flux budget at the ice base, a salt flux budget at the ice base and a linearised freezing point temperature equation). 1007 A complete description is available in \citet{ Jenkins1991}.1051 A complete description is available in \citet{jenkins_JGR91}. 1008 1052 \end{description} 1009 1053 1010 Temperature and salinity used to compute the melt are the average temperature in the top boundary layer \citet{ Losch2008}.1054 Temperature and salinity used to compute the melt are the average temperature in the top boundary layer \citet{losch_JGR08}. 1011 1055 Its thickness is defined by \np{rn\_hisf\_tbl}. 1012 1056 The fluxes and friction velocity are computed using the mean temperature, salinity and velocity in the the first \np{rn\_hisf\_tbl} m. … … 1038 1082 \] 1039 1083 where $u_{*}$ is the friction velocity in the top boundary layer (ie first \np{rn\_hisf\_tbl} meters). 1040 See \citet{ Jenkins2010} for all the details on this formulation. It is the recommended formulation for realistic application.1084 See \citet{jenkins.nicholls.ea_JPO10} for all the details on this formulation. It is the recommended formulation for realistic application. 1041 1085 \item[\np{nn\_gammablk}\forcode{ = 2}]: 1042 1086 The salt and heat exchange coefficients are velocity and stability dependent and defined as: … … 1047 1091 $\Gamma_{Turb}$ the contribution of the ocean stability and 1048 1092 $\Gamma^{T,S}_{Mole}$ the contribution of the molecular diffusion. 1049 See \citet{ Holland1999} for all the details on this formulation.1093 See \citet{holland.jenkins_JPO99} for all the details on this formulation. 1050 1094 This formulation has not been extensively tested in NEMO (not recommended). 1051 1095 \end{description} 1052 \item[\np{nn\_isf}\forcode{ = 2}]:1096 \item[\np{nn\_isf}\forcode{ = 2}]: 1053 1097 The ice shelf cavity is not represented. 1054 The fwf and heat flux are computed using the \citet{ Beckmann2003} parameterisation of isf melting.1098 The fwf and heat flux are computed using the \citet{beckmann.goosse_OM03} parameterisation of isf melting. 1055 1099 The fluxes are distributed along the ice shelf edge between the depth of the average grounding line (GL) 1056 1100 (\np{sn\_depmax\_isf}) and the base of the ice shelf along the calving front 1057 1101 (\np{sn\_depmin\_isf}) as in (\np{nn\_isf}\forcode{ = 3}). 1058 1102 The effective melting length (\np{sn\_Leff\_isf}) is read from a file. 1059 \item[\np{nn\_isf}\forcode{ = 3}]:1103 \item[\np{nn\_isf}\forcode{ = 3}]: 1060 1104 The ice shelf cavity is not represented. 1061 1105 The fwf (\np{sn\_rnfisf}) is prescribed and distributed along the ice shelf edge between … … 1063 1107 the base of the ice shelf along the calving front (\np{sn\_depmin\_isf}). 1064 1108 The heat flux ($Q_h$) is computed as $Q_h = fwf \times L_f$. 1065 \item[\np{nn\_isf}\forcode{ = 4}]:1109 \item[\np{nn\_isf}\forcode{ = 4}]: 1066 1110 The ice shelf cavity is opened (\np{ln\_isfcav}\forcode{ = .true.} needed). 1067 1111 However, the fwf is not computed but specified from file \np{sn\_fwfisf}). … … 1089 1133 \begin{figure}[!t] 1090 1134 \begin{center} 1091 \includegraphics[width= 0.8\textwidth]{Fig_SBC_isf}1135 \includegraphics[width=\textwidth]{Fig_SBC_isf} 1092 1136 \caption{ 1093 1137 \protect\label{fig:SBC_isf} … … 1098 1142 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 1099 1143 1144 1145 1146 % ================================================================ 1147 % Ice sheet coupling 1148 % ================================================================ 1100 1149 \section{Ice sheet coupling} 1101 1150 \label{sec:SBC_iscpl} … … 1104 1153 \nlst{namsbc_iscpl} 1105 1154 %-------------------------------------------------------------------------------------------------------- 1155 1106 1156 Ice sheet/ocean coupling is done through file exchange at the restart step. 1107 1157 At each restart step: 1158 1108 1159 \begin{description} 1109 1160 \item[Step 1]: the ice sheet model send a new bathymetry and ice shelf draft netcdf file. … … 1117 1168 potentially some new wet/dry cells due to the ice sheet dynamics/thermodynamics. 1118 1169 The wetting and drying scheme applied on the restart is very simple and described below for the 6 different possible cases: 1170 1119 1171 \begin{description} 1120 1172 \item[Thin a cell down]: … … 1155 1207 The corrective increment is apply into the cell itself (if it is a wet cell), the neigbouring cells or the closest wet cell (if the cell is now dry). 1156 1208 1157 % 1209 1210 1158 1211 % ================================================================ 1159 1212 % Handling of icebergs … … 1166 1219 %------------------------------------------------------------------------------------------------------------- 1167 1220 1168 Icebergs are modelled as lagrangian particles in NEMO \citep{ Marsh_GMD2015}.1169 Their physical behaviour is controlled by equations as described in \citet{ Martin_Adcroft_OM10} ).1221 Icebergs are modelled as lagrangian particles in NEMO \citep{marsh.ivchenko.ea_GMD15}. 1222 Their physical behaviour is controlled by equations as described in \citet{martin.adcroft_OM10} ). 1170 1223 (Note that the authors kindly provided a copy of their code to act as a basis for implementation in NEMO). 1171 1224 Icebergs are initially spawned into one of ten classes which have specific mass and thickness as … … 1186 1239 the geographical box: lonmin,lonmax,latmin,latmax 1187 1240 \item[\np{nn\_test\_icebergs}\forcode{ = -1}] 1188 In this scheme the model reads a calving file supplied in the \np{sn\_icb} parameter.1241 In this scheme, the model reads a calving file supplied in the \np{sn\_icb} parameter. 1189 1242 This should be a file with a field on the configuration grid (typically ORCA) 1190 1243 representing ice accumulation rate at each model point. … … 1224 1277 since its trajectory data may be spread across multiple files. 1225 1278 1226 % ------------------------------------------------------------------------------------------------------------- 1279 1280 1281 % ============================================================================================================= 1227 1282 % Interactions with waves (sbcwave.F90, ln_wave) 1228 % ------------------------------------------------------------------------------------------------------------- 1229 \section{Interactions with waves (\protect\mdl{sbcwave}, \protect\np{ln\_wave})} 1283 % ============================================================================================================= 1284 \section[Interactions with waves (\textit{sbcwave.F90}, \texttt{ln\_wave})] 1285 {Interactions with waves (\protect\mdl{sbcwave}, \protect\np{ln\_wave})} 1230 1286 \label{sec:SBC_wave} 1231 1287 %------------------------------------------namsbc_wave-------------------------------------------------------- … … 1241 1297 1242 1298 Physical processes related to ocean surface waves can be accounted by setting the logical variable 1243 \np{ln\_wave} \forcode{= .true.} in \ngn{namsbc} namelist. In addition, specific flags accounting for1244 different p orcesses should be activated as explained in the following sections.1299 \np{ln\_wave} \forcode{= .true.} in \ngn{namsbc} namelist. In addition, specific flags accounting for 1300 different processes should be activated as explained in the following sections. 1245 1301 1246 1302 Wave fields can be provided either in forced or coupled mode: … … 1254 1310 1255 1311 1256 % ================================================================1312 % ---------------------------------------------------------------- 1257 1313 % Neutral drag coefficient from wave model (ln_cdgw) 1258 1314 1259 % ================================================================ 1260 \subsection{Neutral drag coefficient from wave model (\protect\np{ln\_cdgw})} 1315 % ---------------------------------------------------------------- 1316 \subsection[Neutral drag coefficient from wave model (\texttt{ln\_cdgw})] 1317 {Neutral drag coefficient from wave model (\protect\np{ln\_cdgw})} 1261 1318 \label{subsec:SBC_wave_cdgw} 1262 1319 1263 1320 The neutral surface drag coefficient provided from an external data source (\ie a wave model), 1264 1321 can be used by setting the logical variable \np{ln\_cdgw} \forcode{= .true.} in \ngn{namsbc} namelist. 1265 Then using the routine \rou{ turb\_ncar} and starting from the neutral drag coefficent provided,1322 Then using the routine \rou{sbcblk\_algo\_ncar} and starting from the neutral drag coefficent provided, 1266 1323 the drag coefficient is computed according to the stable/unstable conditions of the 1267 air-sea interface following \citet{ Large_Yeager_Rep04}.1268 1269 1270 % ================================================================1324 air-sea interface following \citet{large.yeager_rpt04}. 1325 1326 1327 % ---------------------------------------------------------------- 1271 1328 % 3D Stokes Drift (ln_sdw, nn_sdrift) 1272 % ================================================================ 1273 \subsection{3D Stokes Drift (\protect\np{ln\_sdw, nn\_sdrift})} 1329 % ---------------------------------------------------------------- 1330 \subsection[3D Stokes Drift (\texttt{ln\_sdw}, \texttt{nn\_sdrift})] 1331 {3D Stokes Drift (\protect\np{ln\_sdw, nn\_sdrift})} 1274 1332 \label{subsec:SBC_wave_sdw} 1275 1333 1276 The Stokes drift is a wave driven mechanism of mass and momentum transport \citep{ Stokes_1847}.1334 The Stokes drift is a wave driven mechanism of mass and momentum transport \citep{stokes_ibk09}. 1277 1335 It is defined as the difference between the average velocity of a fluid parcel (Lagrangian velocity) 1278 1336 and the current measured at a fixed point (Eulerian velocity). 1279 1337 As waves travel, the water particles that make up the waves travel in orbital motions but 1280 1338 without a closed path. Their movement is enhanced at the top of the orbit and slowed slightly 1281 at the bottom so the result is a net forward motion of water particles, referred to as the Stokes drift.1339 at the bottom, so the result is a net forward motion of water particles, referred to as the Stokes drift. 1282 1340 An accurate evaluation of the Stokes drift and the inclusion of related processes may lead to improved 1283 representation of surface physics in ocean general circulation models. 1341 representation of surface physics in ocean general circulation models. %GS: reference needed 1284 1342 The Stokes drift velocity $\mathbf{U}_{st}$ in deep water can be computed from the wave spectrum and may be written as: 1285 1343 … … 1296 1354 $k=\frac{2\pi}{\lambda}$ (being $\lambda$ the wavelength). \\ 1297 1355 1298 In order to evaluate the Stokes drift in a realistic ocean wave field the wave spectral shape is required1356 In order to evaluate the Stokes drift in a realistic ocean wave field, the wave spectral shape is required 1299 1357 and its computation quickly becomes expensive as the 2D spectrum must be integrated for each vertical level. 1300 1358 To simplify, it is customary to use approximations to the full Stokes profile. … … 1307 1365 \begin{description} 1308 1366 \item[\np{nn\_sdrift} = 0]: exponential integral profile parameterization proposed by 1309 \citet{ Breivik_al_JPO2014}:1367 \citet{breivik.janssen.ea_JPO14}: 1310 1368 1311 1369 \[ … … 1326 1384 1327 1385 \item[\np{nn\_sdrift} = 1]: velocity profile based on the Phillips spectrum which is considered to be a 1328 reasonable estimate of the part of the spectrum most contributing to the Stokes drift velocity near the surface1329 \citep{ Breivik_al_OM2016}:1386 reasonable estimate of the part of the spectrum mostly contributing to the Stokes drift velocity near the surface 1387 \citep{breivik.bidlot.ea_OM16}: 1330 1388 1331 1389 \[ … … 1364 1422 1365 1423 1366 % ================================================================1424 % ---------------------------------------------------------------- 1367 1425 % Stokes-Coriolis term (ln_stcor) 1368 % ================================================================ 1369 \subsection{Stokes-Coriolis term (\protect\np{ln\_stcor})} 1426 % ---------------------------------------------------------------- 1427 \subsection[Stokes-Coriolis term (\texttt{ln\_stcor})] 1428 {Stokes-Coriolis term (\protect\np{ln\_stcor})} 1370 1429 \label{subsec:SBC_wave_stcor} 1371 1430 … … 1378 1437 1379 1438 1380 % ================================================================1439 % ---------------------------------------------------------------- 1381 1440 % Waves modified stress (ln_tauwoc, ln_tauw) 1382 % ================================================================ 1383 \subsection{Wave modified sress (\protect\np{ln\_tauwoc, ln\_tauw})} 1441 % ---------------------------------------------------------------- 1442 \subsection[Wave modified stress (\texttt{ln\_tauwoc}, \texttt{ln\_tauw})] 1443 {Wave modified sress (\protect\np{ln\_tauwoc, ln\_tauw})} 1384 1444 \label{subsec:SBC_wave_tauw} 1385 1445 1386 1446 The surface stress felt by the ocean is the atmospheric stress minus the net stress going 1387 into the waves \citep{ Janssen_al_TM13}. Therefore, when waves are growing, momentum and energy is spent and is not1447 into the waves \citep{janssen.breivik.ea_rpt13}. Therefore, when waves are growing, momentum and energy is spent and is not 1388 1448 available for forcing the mean circulation, while in the opposite case of a decaying sea 1389 state more momentum is available for forcing the ocean.1390 Only when the sea state is in equilibrium the ocean is forced by the atmospheric stress,1391 but in practice an equilibrium sea state is a fairly rare event.1449 state, more momentum is available for forcing the ocean. 1450 Only when the sea state is in equilibrium, the ocean is forced by the atmospheric stress, 1451 but in practice, an equilibrium sea state is a fairly rare event. 1392 1452 So the atmospheric stress felt by the ocean circulation $\tau_{oc,a}$ can be expressed as: 1393 1453 … … 1419 1479 1420 1480 1481 1421 1482 % ================================================================ 1422 1483 % Miscellanea options … … 1425 1486 \label{sec:SBC_misc} 1426 1487 1488 1427 1489 % ------------------------------------------------------------------------------------------------------------- 1428 1490 % Diurnal cycle 1429 1491 % ------------------------------------------------------------------------------------------------------------- 1430 \subsection{Diurnal cycle (\protect\mdl{sbcdcy})} 1492 \subsection[Diurnal cycle (\textit{sbcdcy.F90})] 1493 {Diurnal cycle (\protect\mdl{sbcdcy})} 1431 1494 \label{subsec:SBC_dcy} 1432 %------------------------------------------namsbc _rnf----------------------------------------------------1495 %------------------------------------------namsbc------------------------------------------------------------- 1433 1496 % 1434 1497 \nlst{namsbc} … … 1438 1501 \begin{figure}[!t] 1439 1502 \begin{center} 1440 \includegraphics[width= 0.8\textwidth]{Fig_SBC_diurnal}1503 \includegraphics[width=\textwidth]{Fig_SBC_diurnal} 1441 1504 \caption{ 1442 1505 \protect\label{fig:SBC_diurnal} … … 1445 1508 the mean value of the analytical cycle (blue line) over a time step, 1446 1509 not as the mid time step value of the analytically cycle (red square). 1447 From \citet{ Bernie_al_CD07}.1510 From \citet{bernie.guilyardi.ea_CD07}. 1448 1511 } 1449 1512 \end{center} … … 1451 1514 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> 1452 1515 1453 \cite{Bernie_al_JC05} have shown that to capture 90$\%$ of the diurnal variability of SST requires a vertical resolution in upper ocean of 1~m or better and a temporal resolution of the surface fluxes of 3~h or less. 1454 Unfortunately high frequency forcing fields are rare, not to say inexistent. 1455 Nevertheless, it is possible to obtain a reasonable diurnal cycle of the SST knowning only short wave flux (SWF) at 1456 high frequency \citep{Bernie_al_CD07}. 1516 \cite{bernie.woolnough.ea_JC05} have shown that to capture 90$\%$ of the diurnal variability of SST requires a vertical resolution in upper ocean of 1~m or better and a temporal resolution of the surface fluxes of 3~h or less. 1517 %Unfortunately high frequency forcing fields are rare, not to say inexistent. GS: not true anymore ! 1518 Nevertheless, it is possible to obtain a reasonable diurnal cycle of the SST knowning only short wave flux (SWF) at high frequency \citep{bernie.guilyardi.ea_CD07}. 1457 1519 Furthermore, only the knowledge of daily mean value of SWF is needed, 1458 1520 as higher frequency variations can be reconstructed from them, 1459 1521 assuming that the diurnal cycle of SWF is a scaling of the top of the atmosphere diurnal cycle of incident SWF. 1460 The \cite{ Bernie_al_CD07} reconstruction algorithm is available in \NEMO by1522 The \cite{bernie.guilyardi.ea_CD07} reconstruction algorithm is available in \NEMO by 1461 1523 setting \np{ln\_dm2dc}\forcode{ = .true.} (a \textit{\ngn{namsbc}} namelist variable) when 1462 using CORE bulk formulea (\np{ln\_blk\_core}\forcode{ = .true.}) or1524 using a bulk formulation (\np{ln\_blk}\forcode{ = .true.}) or 1463 1525 the flux formulation (\np{ln\_flx}\forcode{ = .true.}). 1464 1526 The reconstruction is performed in the \mdl{sbcdcy} module. 1465 The detail of the algoritm used can be found in the appendix~A of \cite{ Bernie_al_CD07}.1466 The algorithm preserve the daily mean incoming SWF as the reconstructed SWF at1527 The detail of the algoritm used can be found in the appendix~A of \cite{bernie.guilyardi.ea_CD07}. 1528 The algorithm preserves the daily mean incoming SWF as the reconstructed SWF at 1467 1529 a given time step is the mean value of the analytical cycle over this time step (\autoref{fig:SBC_diurnal}). 1468 1530 The use of diurnal cycle reconstruction requires the input SWF to be daily 1469 (\ie a frequency of 24 and a time interpolation set to true in \np{sn\_qsr} namelist parameter).1470 Furthermore, it is recommended to have a least 8 surface module time step per day,1531 (\ie a frequency of 24 hours and a time interpolation set to true in \np{sn\_qsr} namelist parameter). 1532 Furthermore, it is recommended to have a least 8 surface module time steps per day, 1471 1533 that is $\rdt \ nn\_fsbc < 10,800~s = 3~h$. 1472 1534 An example of recontructed SWF is given in \autoref{fig:SBC_dcy} for a 12 reconstructed diurnal cycle, … … 1476 1538 \begin{figure}[!t] 1477 1539 \begin{center} 1478 \includegraphics[width= 0.7\textwidth]{Fig_SBC_dcy}1540 \includegraphics[width=\textwidth]{Fig_SBC_dcy} 1479 1541 \caption{ 1480 1542 \protect\label{fig:SBC_dcy} … … 1491 1553 an inconsistency between the scale of the vertical resolution and the forcing acting on that scale. 1492 1554 1555 1493 1556 % ------------------------------------------------------------------------------------------------------------- 1494 1557 % Rotation of vector pairs onto the model grid directions … … 1497 1560 \label{subsec:SBC_rotation} 1498 1561 1499 When using a flux (\np{ln\_flx}\forcode{ = .true.}) or 1500 bulk (\np{ln\_clio}\forcode{ = .true.} or \np{ln\_core}\forcode{ = .true.}) formulation, 1562 When using a flux (\np{ln\_flx}\forcode{ = .true.}) or bulk (\np{ln\_blk}\forcode{ = .true.}) formulation, 1501 1563 pairs of vector components can be rotated from east-north directions onto the local grid directions. 1502 1564 This is particularly useful when interpolation on the fly is used since here any vectors are likely to 1503 1565 be defined relative to a rectilinear grid. 1504 To activate this option a non-empty string is supplied in the rotation pair column of the relevant namelist.1566 To activate this option, a non-empty string is supplied in the rotation pair column of the relevant namelist. 1505 1567 The eastward component must start with "U" and the northward component with "V". 1506 1568 The remaining characters in the strings are used to identify which pair of components go together. … … 1511 1573 The rot\_rep routine from the \mdl{geo2ocean} module is used to perform the rotation. 1512 1574 1575 1513 1576 % ------------------------------------------------------------------------------------------------------------- 1514 1577 % Surface restoring to observed SST and/or SSS 1515 1578 % ------------------------------------------------------------------------------------------------------------- 1516 \subsection{Surface restoring to observed SST and/or SSS (\protect\mdl{sbcssr})} 1579 \subsection[Surface restoring to observed SST and/or SSS (\textit{sbcssr.F90})] 1580 {Surface restoring to observed SST and/or SSS (\protect\mdl{sbcssr})} 1517 1581 \label{subsec:SBC_ssr} 1518 1582 %------------------------------------------namsbc_ssr---------------------------------------------------- … … 1521 1585 %------------------------------------------------------------------------------------------------------------- 1522 1586 1523 IOptions are defined through the \ngn{namsbc\_ssr} namelist variables.1587 Options are defined through the \ngn{namsbc\_ssr} namelist variables. 1524 1588 On forced mode using a flux formulation (\np{ln\_flx}\forcode{ = .true.}), 1525 1589 a feedback term \emph{must} be added to the surface heat flux $Q_{ns}^o$: … … 1546 1610 (observed, climatological or an atmospheric model product), 1547 1611 \textit{SSS}$_{Obs}$ is a sea surface salinity 1548 (usually a time interpolation of the monthly mean Polar Hydrographic Climatology \citep{ Steele2001}),1612 (usually a time interpolation of the monthly mean Polar Hydrographic Climatology \citep{steele.morley.ea_JC01}), 1549 1613 $\left.S\right|_{k=1}$ is the model surface layer salinity and 1550 1614 $\gamma_s$ is a negative feedback coefficient which is provided as a namelist parameter. 1551 1615 Unlike heat flux, there is no physical justification for the feedback term in \autoref{eq:sbc_dmp_emp} as 1552 the atmosphere does not care about ocean surface salinity \citep{ Madec1997}.1616 the atmosphere does not care about ocean surface salinity \citep{madec.delecluse_IWN97}. 1553 1617 The SSS restoring term should be viewed as a flux correction on freshwater fluxes to 1554 1618 reduce the uncertainties we have on the observed freshwater budget. 1619 1555 1620 1556 1621 % ------------------------------------------------------------------------------------------------------------- … … 1578 1643 This prevents deep convection to occur when trying to reach the freezing point 1579 1644 (and so ice covered area condition) while the SSS is too large. 1580 This manner of managing sea-ice area, just by using siIF case,1645 This manner of managing sea-ice area, just by using a IF case, 1581 1646 is usually referred as the \textit{ice-if} model. 1582 1647 It can be found in the \mdl{sbcice{\_}if} module. … … 1585 1650 This model computes the ice-ocean fluxes, 1586 1651 that are combined with the air-sea fluxes using the ice fraction of each model cell to 1587 provide the surface ocean fluxes.1588 Note that the activation of a sea-ice model is is done by defining a CPP key (\key{lim3} or \key{cice}).1652 provide the surface averaged ocean fluxes. 1653 Note that the activation of a sea-ice model is done by defining a CPP key (\key{si3} or \key{cice}). 1589 1654 The activation automatically overwrites the read value of nn{\_}ice to its appropriate value 1590 (\ie $2$ for LIM-3 or $3$ for CICE).1655 (\ie $2$ for SI3 or $3$ for CICE). 1591 1656 \end{description} 1592 1657 1593 1658 % {Description of Ice-ocean interface to be added here or in LIM 2 and 3 doc ?} 1594 1595 \subsection{Interface to CICE (\protect\mdl{sbcice\_cice})} 1659 %GS: ocean-ice (SI3) interface is not located in SBC directory anymore, so it should be included in SI3 doc 1660 1661 1662 % ------------------------------------------------------------------------------------------------------------- 1663 % CICE-ocean Interface 1664 % ------------------------------------------------------------------------------------------------------------- 1665 \subsection[Interface to CICE (\textit{sbcice\_cice.F90})] 1666 {Interface to CICE (\protect\mdl{sbcice\_cice})} 1596 1667 \label{subsec:SBC_cice} 1597 1668 1598 It is nowpossible to couple a regional or global NEMO configuration (without AGRIF)1669 It is possible to couple a regional or global NEMO configuration (without AGRIF) 1599 1670 to the CICE sea-ice model by using \key{cice}. 1600 1671 The CICE code can be obtained from \href{http://oceans11.lanl.gov/trac/CICE/}{LANL} and … … 1603 1674 and CICE CPP keys \textbf{ORCA\_GRID}, \textbf{CICE\_IN\_NEMO} and \textbf{coupled} should be used 1604 1675 (seek advice from UKMO if necessary). 1605 Currently the code is only designed to work when using the CORE forcing option for NEMO1676 Currently, the code is only designed to work when using the NCAR forcing option for NEMO %GS: still true ? 1606 1677 (with \textit{calc\_strair}\forcode{ = .true.} and \textit{calc\_Tsfc}\forcode{ = .true.} in the CICE name-list), 1607 1678 or alternatively when NEMO is coupled to the HadGAM3 atmosphere model … … 1623 1694 there is no sea ice. 1624 1695 1696 1625 1697 % ------------------------------------------------------------------------------------------------------------- 1626 1698 % Freshwater budget control 1627 1699 % ------------------------------------------------------------------------------------------------------------- 1628 \subsection{Freshwater budget control (\protect\mdl{sbcfwb})} 1700 \subsection[Freshwater budget control (\textit{sbcfwb.F90})] 1701 {Freshwater budget control (\protect\mdl{sbcfwb})} 1629 1702 \label{subsec:SBC_fwb} 1630 1703 1631 For global ocean simulation it can be useful to introduce a control of the mean sea level in order to1704 For global ocean simulation, it can be useful to introduce a control of the mean sea level in order to 1632 1705 prevent unrealistic drift of the sea surface height due to inaccuracy in the freshwater fluxes. 1633 In \NEMO, two way of controlling the the freshwater budget. 1706 In \NEMO, two way of controlling the freshwater budget are proposed: 1707 1634 1708 \begin{description} 1635 1709 \item[\np{nn\_fwb}\forcode{ = 0}] … … 1638 1712 \item[\np{nn\_fwb}\forcode{ = 1}] 1639 1713 global mean \textit{emp} set to zero at each model time step. 1640 %Note that with a sea-ice model, this technique only control the mean sea level with linear free surface (\key{vvl} not defined) and no mass flux between ocean and ice (as it is implemented in the current ice-ocean coupling). 1714 %GS: comment below still relevant ? 1715 %Note that with a sea-ice model, this technique only controls the mean sea level with linear free surface and no mass flux between ocean and ice (as it is implemented in the current ice-ocean coupling). 1641 1716 \item[\np{nn\_fwb}\forcode{ = 2}] 1642 1717 freshwater budget is adjusted from the previous year annual mean budget which … … 1645 1720 the change in the mean sea level at January the first and saved in the \textit{EMPav.dat} file. 1646 1721 \end{description} 1647 1648 1649 1722 1650 1723 % Griffies doc: … … 1655 1728 % The result of the normalization should be a global integrated zero net water input to the ocean-ice system over 1656 1729 % a chosen time scale. 1657 % How often the normalization is done is a matter of choice. In mom4p1, we choose to do so at each model time step,1730 % How often the normalization is done is a matter of choice. In mom4p1, we choose to do so at each model time step, 1658 1731 % so that there is always a zero net input of water to the ocean-ice system. 1659 1732 % Others choose to normalize over an annual cycle, in which case the net imbalance over an annual cycle is used … … 1670 1743 % in ocean-ice models. 1671 1744 1745 1672 1746 \biblio 1673 1747
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