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- 2013-11-04T12:51:55+01:00 (10 years ago)
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branches/2013/dev_LOCEAN_2013/DOC/TexFiles/Chapters/Chap_SBC.tex
r3795 r4147 1 1 % ================================================================ 2 % Chapter ÑSurface Boundary Condition (SBC, ICB)2 % Chapter � Surface Boundary Condition (SBC, ICB) 3 3 % ================================================================ 4 4 \chapter{Surface Boundary Condition (SBC, ICB) } … … 25 25 26 26 Five different ways to provide the first six fields to the ocean are available which 27 are controlled by namelist variables: an analytical formulation (\np{ln\_ana}~=~true),27 are controlled by namelist \ngn{namsbc} variables: an analytical formulation (\np{ln\_ana}~=~true), 28 28 a flux formulation (\np{ln\_flx}~=~true), a bulk formulae formulation (CORE 29 29 (\np{ln\_core}~=~true), CLIO (\np{ln\_clio}~=~true) or MFS … … 442 442 %-------------------------------------------------------------------------------------------------------------- 443 443 444 In some circumstances it may be useful to avoid calculating the 3D temperature, salinity and velocity fields and 445 simply read them in from a previous run. For example: 444 In some circumstances it may be useful to avoid calculating the 3D temperature, salinity and velocity fields and simply read them in from a previous run. 445 Options are defined through the \ngn{namsbc\_sas} namelist variables. 446 For example: 446 447 447 448 \begin{enumerate} … … 507 508 In this case, all the six fluxes needed by the ocean are assumed to 508 509 be uniform in space. They take constant values given in the namelist 509 namsbc{\_}anaby the variables \np{rn\_utau0}, \np{rn\_vtau0}, \np{rn\_qns0},510 \ngn{namsbc{\_}ana} by the variables \np{rn\_utau0}, \np{rn\_vtau0}, \np{rn\_qns0}, 510 511 \np{rn\_qsr0}, and \np{rn\_emp0} ($\textit{emp}=\textit{emp}_S$). The runoff is set to zero. 511 512 In addition, the wind is allowed to reach its nominal value within a given number … … 530 531 In the flux formulation (\np{ln\_flx}=true), the surface boundary 531 532 condition fields are directly read from input files. The user has to define 532 in the namelist namsbc{\_}flxthe name of the file, the name of the variable533 in the namelist \ngn{namsbc{\_}flx} the name of the file, the name of the variable 533 534 read in the file, the time frequency at which it is given (in hours), and a logical 534 535 setting whether a time interpolation to the model time step is required … … 580 581 This is the so-called DRAKKAR Forcing Set (DFS) \citep{Brodeau_al_OM09}. 581 582 583 Options are defined through the \ngn{namsbc\_core} namelist variables. 582 584 The required 8 input fields are: 583 585 … … 621 623 compute the radiative fluxes from a climatological cloud cover. 622 624 625 Options are defined through the \ngn{namsbc\_clio} namelist variables. 623 626 The required 7 input fields are: 624 627 … … 673 676 Details on the bulk formulae used can be found in \citet{Maggiore_al_PCE98} and \citet{Castellari_al_JMS1998}. 674 677 678 Options are defined through the \ngn{namsbc\_mfs} namelist variables. 675 679 The required 7 input fields must be provided on the model Grid-T and are: 676 680 \begin{itemize} … … 711 715 When PISCES biogeochemical model (\key{top} and \key{pisces}) is also used in the coupled system, 712 716 the whole carbon cycle is computed by defining \key{cpl\_carbon\_cycle}. In this case, 713 CO$_2$ fluxes will be exchanged between the atmosphere and the ice-ocean system (and need to be activated 714 in namsbc{\_}cpl). 715 716 The new namelist above allows control of various aspects of the coupling fields (particularly for 717 CO$_2$ fluxes will be exchanged between the atmosphere and the ice-ocean system (and need to be activated in \ngn{namsbc{\_}cpl} ). 718 719 The namelist above allows control of various aspects of the coupling fields (particularly for 717 720 vectors) and now allows for any coupling fields to have multiple sea ice categories (as required by LIM3 718 721 and CICE). When indicating a multi-category coupling field in namsbc{\_}cpl the number of categories will be … … 736 739 737 740 The optional atmospheric pressure can be used to force ocean and ice dynamics 738 (\np{ln\_apr\_dyn}~=~true, \textit{ namsbc} namelist ).741 (\np{ln\_apr\_dyn}~=~true, \textit{\ngn{namsbc}} namelist ). 739 742 The input atmospheric forcing defined via \np{sn\_apr} structure (\textit{namsbc\_apr} namelist) 740 743 can be interpolated in time to the model time step, and even in space when the … … 774 777 %------------------------------------------------------------------------------------------------------------- 775 778 776 Concerning the tidal potential, some parameters are available in namelist :777 778 - \ texttt{ln\_tide\_pot} activate the tidal potential forcing779 780 - \ texttt{nb\_harmo} is the number of constituent used781 782 - \ texttt{clname} is the name of constituent779 Concerning the tidal potential, some parameters are available in namelist \ngn{nam\_tide}: 780 781 - \np{ln\_tide\_pot} activate the tidal potential forcing 782 783 - \np{nb\_harmo} is the number of constituent used 784 785 - \np{clname} is the name of constituent 783 786 784 787 … … 858 861 depth (in metres) which the river should be added to. 859 862 860 Namelist options, \np{ln\_rnf\_depth}, \np{ln\_rnf\_sal} and \np{ln\_rnf\_temp} control whether863 Namelist variables in \ngn{namsbc\_rnf}, \np{ln\_rnf\_depth}, \np{ln\_rnf\_sal} and \np{ln\_rnf\_temp} control whether 861 864 the river attributes (depth, salinity and temperature) are read in and used. If these are set 862 865 as false the river is added to the surface box only, assumed to be fresh (0~psu), and/or … … 943 946 Their physical behaviour is controlled by equations as described in \citet{Martin_Adcroft_OM10} ). 944 947 (Note that the authors kindly provided a copy of their code to act as a basis for implementation in NEMO.) 945 Icebergs are initially spawned into one of ten classes which have specific mass and thickness as described by948 Icebergs are initially spawned into one of ten classes which have specific mass and thickness as described in the \ngn{namberg} namelist: 946 949 \np{rn\_initial\_mass} and \np{rn\_initial\_thickness}. 947 950 Each class has an associated scaling (\np{rn\_mass\_scaling}), which is an integer representing how many icebergs … … 1031 1034 the diurnal cycle of SWF is a scaling of the top of the atmosphere diurnal cycle 1032 1035 of incident SWF. The \cite{Bernie_al_CD07} reconstruction algorithm is available 1033 in \NEMO by setting \np{ln\_dm2dc}~=~true (a \textit{ namsbc} namelist parameter) when using1036 in \NEMO by setting \np{ln\_dm2dc}~=~true (a \textit{\ngn{namsbc}} namelist variable) when using 1034 1037 CORE bulk formulea (\np{ln\_blk\_core}~=~true) or the flux formulation (\np{ln\_flx}~=~true). 1035 1038 The reconstruction is performed in the \mdl{sbcdcy} module. The detail of the algoritm used … … 1088 1091 %------------------------------------------------------------------------------------------------------------- 1089 1092 1090 In forced mode using a flux formulation (\np{ln\_flx}~=~true), a 1093 IOptions are defined through the \ngn{namsbc\_ssr} namelist variables. 1094 n forced mode using a flux formulation (\np{ln\_flx}~=~true), a 1091 1095 feedback term \emph{must} be added to the surface heat flux $Q_{ns}^o$: 1092 1096 \begin{equation} \label{Eq_sbc_dmp_q} … … 1212 1216 in $namsbc$ namelist must be defined ${.true.}$. 1213 1217 The \mdl{sbcwave} module containing the routine \np{sbc\_wave} reads the 1214 namelist ${namsbc\_wave}$(for external data names, locations, frequency, interpolation and all1218 namelist \ngn{namsbc\_wave} (for external data names, locations, frequency, interpolation and all 1215 1219 the miscellanous options allowed by Input Data generic Interface see \S\ref{SBC_input}) 1216 1220 and a 2D field of neutral drag coefficient. Then using the routine … … 1222 1226 % Griffies doc: 1223 1227 % When running ocean-ice simulations, we are not explicitly representing land processes, such as rivers, catchment areas, snow accumulation, etc. However, to reduce model drift, it is important to balance the hydrological cycle in ocean-ice models. We thus need to prescribe some form of global normalization to the precipitation minus evaporation plus river runoff. The result of the normalization should be a global integrated zero net water input to the ocean-ice system over a chosen time scale. 1224 %How often the normalization is done is a matter of choice. In mom4p1, we choose to do so at each model time step, so that there is always a zero net input of water to the ocean-ice system. Others choose to normalize over an annual cycle, in which case the net imbalance over an annual cycle is used to alter the subsequent year Õs water budget in an attempt to damp the annual water imbalance. Note that the annual budget approach may be inappropriate with interannually varying precipitation forcing.1228 %How often the normalization is done is a matter of choice. In mom4p1, we choose to do so at each model time step, so that there is always a zero net input of water to the ocean-ice system. Others choose to normalize over an annual cycle, in which case the net imbalance over an annual cycle is used to alter the subsequent year�s water budget in an attempt to damp the annual water imbalance. Note that the annual budget approach may be inappropriate with interannually varying precipitation forcing. 1225 1229 %When running ocean-ice coupled models, it is incorrect to include the water transport between the ocean and ice models when aiming to balance the hydrological cycle. The reason is that it is the sum of the water in the ocean plus ice that should be balanced when running ocean-ice models, not the water in any one sub-component. As an extreme example to illustrate the issue, consider an ocean-ice model with zero initial sea ice. As the ocean-ice model spins up, there should be a net accumulation of water in the growing sea ice, and thus a net loss of water from the ocean. The total water contained in the ocean plus ice system is constant, but there is an exchange of water between the subcomponents. This exchange should not be part of the normalization used to balance the hydrological cycle in ocean-ice models. 1226 1230
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