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 20101017T17:42:40+02:00 (11 years ago)
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branches/nemo_v3_3_beta/DOC/TexFiles/Chapters/Chap_TRA.tex
r2285 r2286 83 83 by using the following equality : $\nabla \cdot \left( \vect{U}\,T \right)=\vect{U} \cdot \nabla T$ 84 84 which results from the use of the continuity equation, $\nabla \cdot \vect{U}=0$ or 85 $ \partial _t e_3 + e_3\;\nabla \cdot \vect{U}=0$ in constant or variable volume case, respectively.85 $ \partial _t e_3 + e_3\;\nabla \cdot \vect{U}=0$ in constant volume or variable volume case, respectively. 86 86 Therefore it is of paramount importance to design the discrete analogue of the 87 87 advection tendency so that it is consistent with the continuity equation in order to … … 152 152 which is advected} 153 153 , implying that false extrema are permitted. Their use is not recommended on passive tracers ; 154 (3) It is highlyrecommended that the same advectiondiffusion scheme is154 (3) It is recommended that the same advectiondiffusion scheme is 155 155 used on both active and passive tracers. Indeed, if a source or sink of a 156 156 passive tracer depends on an active one, the difference of treatment of 157 157 active and passive tracers can create very nicelooking frontal structures 158 that are pure numerical artefacts. 159 160 \sgacomment{not sure whether 3 is still relevant after TRATRC branch is merged in?} 158 that are pure numerical artefacts. Nevertheless, most of our users set a different 159 treatment on passive and active tracers, that's the reason why this possibility 160 is offered. We strongly suggest them to perform a sensitivity experiment 161 using a same treatment to assess the robustness of their results. 162 161 163 %  162 164 % 2nd order centred scheme … … 185 187 with coarse resolution, and the vicinity of ice cover area ($i.e.$ when the ocean 186 188 temperature is close to the freezing point). 187 This combined scheme has been included for specific grid points in the ORCA2 and ORCA4 configurations only. 189 This combined scheme has been included for specific grid points in the ORCA2 190 and ORCA4 configurations only. This is an obsolescent feature as the recommended 191 advection scheme for the ORCA configuration is TVD (see \S\ref{TRA_adv_tvd}). 188 192 189 193 Note that using the cen2 scheme, the overall tracer advection is of second … … 665 669 666 670 In the current version, the situation is a little bit more complicated. } 671 667 672 The surface module (\mdl{sbcmod}, see \S\ref{SBC}) provides the following 668 673 forcing fields (used on tracers): … … 864 869 nonzero heat flux across the seafloor that is associated with solid 865 870 earth cooling. This flux is weak compared to surface fluxes (a mean 866 global value of $\sim0.1\;W/m^2$ \citep{Stein_Stein_Nat92}), but it is867 systematically positive \sgacomment{positive definite?}and acts on the densest water masses.871 global value of $\sim0.1\;W/m^2$ \citep{Stein_Stein_Nat92}), but it warms 872 systematically the ocean and acts on the densest water masses. 868 873 Taking this flux into account in a global ocean model increases 869 874 the deepest overturning cell ($i.e.$ the one associated with the Antarctic … … 910 915 implementation of the BBL, only the tracers are modified, not the velocities. 911 916 Furthermore, it only connects ocean bottom cells, and therefore does not include 912 the improvements introduced by \citet{Campin_Goosse_Tel99}.917 all the improvements introduced by \citet{Campin_Goosse_Tel99}. 913 918 914 919 % 
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