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Changeset 11685 – NEMO

# Changeset 11685

Ignore:
Timestamp:
2019-10-11T00:16:22+02:00 (3 years ago)
Message:

 r11684 % ------------------------------------------------------------------------------------------------------------- \subsection[OSM: OSMOSIS boundary layer scheme (\forcode{ln_zdfosm = .true.})] {OSM: OSMOSIS boundary layer scheme (\protect\np{ln_zdfosm}{ln\_zdfosm}\forcode{ = .true.})} {OSM: OSMOSIS boundary layer scheme (\protect\np{ln_zdfosm}{ln\_zdfosm})} \label{subsec:ZDF_osm} \protect\np{rn_m_la}{rn\_m\_la} is 0.3. The Stokes penetration depth $\delta =$ \protect\np{rn_osm_dstokes}{rn\_osm\_dstokes}; this has default value of \SI{5}{m}. of 5~m. \item \protect\np[=1]{nn_osm_wave}{nn\_osm\_wave} In this case the Stokes drift is spectrum.  Significant wave height and wave-mean period taken from this spectrum are used to calculate the Stokes penetration depth, following the approach set out in Breivik(XXxx) depth, following the approach set out in  \citet{breivik.janssen.ea_JPO14}. \item \protect\np[=2]{nn\_osm_wave}{nn\_osm\_wave} In this case the Stokes drift is \item \protect\np[=2]{nn_osm_wave}{nn\_osm\_wave} In this case the Stokes drift is taken from  ECMWF wave model output, though only the component parallel to the wind stress is retained. Significant wave height and wave-mean period from ECMWF wave model output are used to calculate the Stokes penetration depth, following the approach set out in Breivik(XXxx). depth, again following \citet{breivik.janssen.ea_JPO14}. \end{description} \item \protect\np{ln_kpprimix} {ln\_kpprimix}  Default is \np{.true.}. Switches on KPP-style Ri \#-dependent mixing below the surface boundary layer. If this is set \np{.true.}  the following variable settings are honoured: \texttt{.true.}  the following variable settings are honoured: \item \protect\np{rn_riinfty}{rn\_riinfty} Critical value of local Ri \# below which shear instability increases vertical mixing from background value. \item \protect\np{rn_difri} {rn\_difri} Maximum value of Ri \#-dependent mixing at $\mathrm{Ri}=0$. \item \protect\np{ln_convmix}{ln\_convmix} If \texttt{.true.} then, where water column is unstable, specify diffusivity equal to \protect\np{rn_dif_conv}{rn\_dif\_conv} (default value is 1 ms$^{-2}$). diffusivity equal to \protect\np{rn_dif_conv}{rn\_dif\_conv} (default value is 1 m~s$^{-2}$). \end{description} Diagnostic output is controlled by: mixing. Not taken account of. \item \protect\np{rn_osm_hbl0} {rn\_osm\_hbl0} Depth of initial boundary layer is now set by a density criterion similar to that used in calculating hmlp (output as mldr10_1) in zdfmxl.F90. by a density criterion similar to that used in calculating \emph{hmlp} (output as \texttt{mldr10\_1}) in \mdl{zdfmxl}. \end{description} The OSMOSIS model is fundamentally based on results of Large Eddy Simulations (LES) of Langmuir turbulence and aims to fully describe this Langmuir regime. The description in this section is of necessity incomplete and further details are available in the manuscript The OSMOSIS scheme'', Grant. A (2019); in prep. this Langmuir regime. The description in this section is of necessity incomplete and further details are available in Grant. A (2019); in prep. The OSMOSIS turbulent closure scheme is a similarity-scale scheme in \frac{\partial h_\mathrm{bl}}{\partial t} = W_b - \frac{{\overline{w^\prime b^\prime}}_\mathrm{ent}}{\Delta B_\mathrm{bl}} where $h_\mathrm{bl}$ is the horizontally-varying depth of the OSBL, $\mathbf{U}_b$ and $W_b$ are the mean horizontal and vertical velocities at the base of the OSBL, ${\overline{w^\prime b^\prime}}_\mathrm{ent}$ is the buoyancy flux due to entrainment and $\Delta B_\mathrm{bl}$ is the difference between the buoyancy averaged over the depth of the OSBL (i.e.\ including the ML and pycnocline) and the buoyancy just below the base of the OSBL. This equation for the case when the pycnocline has a finite thickness, based on the potential energy budget of the OSBL, is the leading term \citep{grant+etal18} of a generalization of that used in mixed-layer models \citet[e.g.][]{kraus.turner_tellus67}, in which the thickness of the pycnocline is taken to be zero. where $h_\mathrm{bl}$ is the horizontally-varying depth of the OSBL, $\mathbf{U}_b$ and $W_b$ are the mean horizontal and vertical velocities at the base of the OSBL, ${\overline{w^\prime b^\prime}}_\mathrm{ent}$ is the buoyancy flux due to entrainment and $\Delta B_\mathrm{bl}$ is the difference between the buoyancy averaged over the depth of the OSBL (i.e.\ including the ML and pycnocline) and the buoyancy just below the base of the OSBL. This equation for the case when the pycnocline has a finite thickness, based on the potential energy budget of the OSBL, is the leading term \citep{grant+etal18} of a generalization of that used in mixed-layer models e.g.\ \citet{kraus.turner_tellus67}, in which the thickness of the pycnocline is taken to be zero. The entrainment flux for the combination of convective and Langmuir turbulence is given by