# Changeset 11682

Ignore:
Timestamp:
2019-10-11T00:16:02+02:00 (12 months ago)
Message:

Sunday

File:
1 edited

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 r11681 surface drift and penetration depth. There are three options: \begin{enumerate} \item \texttt{nn_osm_wave=0}. In this case the Stokes drift is \item \np{nn\_osm\_wave=0}. Default value in \texttt{namelist\_ref}. In this case the Stokes drift is assumed to be parallel to the surface wind stress, with magnitude consistent with a constant turbulent Langmuir number $\mathrm{La}_t= \texttt{rn_m_la}$ i.e.\ $u_[s0}=\tau/(\texttt{rn_m_la}^2\rho_0)$. \item \texttt{nn_osm_wave=1}. In this case the Stokes drift is $\mathrm{La}_t=$ \np{rn\_m\_la} i.e.\ $u_{s0}=\tau/(\np{rn\_m\_la}^2\rho_0)$.  Default value of \np{rn\_m\_la} is 0.3. The Stokes penetration depth $\delta =$ \np{rn\_osm\_dstokes}; this has default value of \SI{5 m}. \item \np{nn\_osm\_wave=1}. In this case the Stokes drift is assumed to be parallel to the surface wind stress, with magnitude as in the classical Pierson-Moskowitz wind-sea spectrum. \item \texttt{nn_osm_wave=2}. In this case the Stokes drift is taken from  ECMWF wave model output. Significant wave height and wave-mean period are used to calciulate the Stokes penetration depth, followingh the approach set out in Breivik(XXxx) 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) \item \np{nn\_osm\_wave=2}. 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). \end{enumerate} Others refer to the treatment of diffusion and viscosity beneath the surface boundary layer: \begin{enumerate} \item \np{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: \item \np{rn\_riinfty}. Critical value of local Ri # below which shear instability increases vertical mixing from background value. \item \np{rn\_difri}. Critical value of local Ri # below which shear instability increases vertical mixing from background value. \end{enumerate} and the last to diagnostic outputs: \begin{list} \item \np{ln\_dia\_osm}. Default is \np{.false.}; allows XIOS output of OSMOSIS internal fields. \end{list} Obsolete namelist parameters include: \begin{enumerate} \item \np{ln\_use\_osm\_la}. With \np{nn\_osm\_wave=0}, \np{rn\_osm\_dstokes} is always used to specify the Stokes penetration depth. \item \np{nn\_ave}. Choice of averaging method for KPP-style Ri# mixing. Not taken account of. \item \np{rn\_osm\_hbl0} \item \np{ln\_dia\_osm} \end{enumerate} \subsubsection{Summary} Much of the time the turbulent motions in the ocean surface boundary