Changeset 15522 for NEMO/trunk/doc
- Timestamp:
- 2021-11-18T19:52:07+01:00 (3 years ago)
- Location:
- NEMO/trunk/doc
- Files:
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- 7 edited
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NEMO/trunk/doc/latex/NEMO/main/bibliography.bib
r14374 r15522 563 563 } 564 564 565 @article{ couvelard_2020, 566 author = "X. Couvelard and F. Lemari{\'e} and G. Samson and J.-L. Redelsperger and F. Ardhuin and R. Benshila and G. Madec", 567 doi = "10.5194/gmd-13-3067-2020", 568 journal = "Geosci. Model Dev", 569 month = "Jul", 570 pages = "3067--3090", 571 title = "Development of a two-way-coupled ocean--wave model: assessment on a global NEMO(v3.6)--WW3(v6.02) coupled configuration", 572 volume = "13", 573 year = "2020", 574 } 575 565 576 @article{ cox_OM87, 566 577 title = "Isopycnal diffusion in a z-coordinate ocean model", -
NEMO/trunk/doc/latex/NEMO/subfiles/chap_SBC.tex
r14530 r15522 78 78 (\np[=.true.]{ln_dm2dc}{ln\_dm2dc}), 79 79 \item the activation of wave effects from an external wave model (\np[=.true.]{ln_wave}{ln\_wave}), 80 \item a neutral drag coefficient is read from an external wave model (\np[=.true.]{ln_cdgw}{ln\_cdgw}), 81 \item the Stokes drift from an external wave model is accounted for (\np[=.true.]{ln_sdw}{ln\_sdw}), 82 \item the choice of the Stokes drift profile parameterization (\np[=0..2]{nn_sdrift}{nn\_sdrift}), 83 \item the surface stress given to the ocean is modified by surface waves (\np[=.true.]{ln_tauwoc}{ln\_tauwoc}), 84 \item the surface stress given to the ocean is read from an external wave model (\np[=.true.]{ln_tauw}{ln\_tauw}), 85 \item the Stokes-Coriolis term is included (\np[=.true.]{ln_stcor}{ln\_stcor}), 86 \item the light penetration in the ocean (\np[=.true.]{ln_traqsr}{ln\_traqsr} with namelist \nam{tra_qsr}{tra\_qsr}), 80 \item the light penetration in the ocean (\np[=.true.]{ln_traqsr}{ln\_traqsr} with \nam{tra_qsr}{tra\_qsr}), 87 81 \item the atmospheric surface pressure gradient effect on ocean and ice dynamics (\np[=.true.]{ln_apr_dyn}{ln\_apr\_dyn} with namelist \nam{sbc_apr}{sbc\_apr}), 88 82 \item the effect of sea-ice pressure on the ocean (\np[=.true.]{ln_ice_embd}{ln\_ice\_embd}). … … 171 165 172 166 %\colorbox{yellow}{Penser a} mettre dans le restant l'info nn\_fsbc ET nn\_fsbc*rdt de sorte de reinitialiser la moyenne si on change la frequence ou le pdt 167 173 168 174 169 %% ================================================================================================= … … 720 715 respectively (found in \textit{sbcblk\_skin\_ecmwf.F90}). 721 716 717 718 722 719 \subsubsection{COARE 3.x} 723 720 … … 906 903 In this case, CO$_2$ fluxes will be exchanged between the atmosphere and the ice-ocean system 907 904 (and need to be activated in \nam{sbc_cpl}{sbc\_cpl} ). 905 906 907 When an external wave model (see \autoref{sec:SBC_wave}) is used in the coupled system, wave parameters, surface currents and sea surface height can be exchanged between both models (and need to be activated in \nam{sbc_cpl}{sbc\_cpl} ). 908 908 909 909 910 The namelist above allows control of various aspects of the coupling fields (particularly for vectors) and … … 1572 1573 Ocean waves represent the interface between the ocean and the atmosphere, so \NEMO\ is extended to incorporate 1573 1574 physical processes related to ocean surface waves, namely the surface stress modified by growth and 1574 dissipation of the oceanic wave field, the Stokes-Coriolis force and the Stokes drift impact on mass and 1575 tracer advection; moreover the neutral surface drag coefficient from a wave model can be used to evaluate 1576 the wind stress. 1575 dissipation of the oceanic wave field, the Stokes-Coriolis force, the vortex-force, the Bernoulli head J term and the Stokes drift impact on mass and tracer advection; moreover the neutral surface drag coefficient or the Charnock parameter from a wave model can be used to evaluate the wind stress. NEMO has also been extended to take into account the impact of surface waves on the vertical mixing, via the parameterization of the Langmuir turbulence, the modification of the surface boundary conditions for the Turbulent Kinetic Energy closure scheme, and the inclusion the Stokes drift contribution to the shear production term in different turbulent closure schemes (RIC, TKE, GLS).\\ 1577 1576 1578 1577 Physical processes related to ocean surface waves can be accounted by setting the logical variable 1579 1578 \np[=.true.]{ln_wave}{ln\_wave} in \nam{sbc}{sbc} namelist. In addition, specific flags accounting for 1580 different processes should be activated as explained in the following sections. 1579 different processes should be activated as explained in the following sections.\\ 1581 1580 1582 1581 Wave fields can be provided either in forced or coupled mode: 1583 1582 \begin{description} 1584 \item [forced mode]: wave fields should be defined through the \nam{sbc_wave}{sbc\_wave} namelist 1583 \item [forced mode]: the neutral drag coefficient, the two components of the surface Stokes drift, the significant wave height, the mean wave period, the mean wave number, and the normalized 1584 wave stress going into the ocean can be read from external files. Wave fields should be defined through the \nam{sbc_wave}{sbc\_wave} namelist 1585 1585 for external data names, locations, frequency, interpolation and all the miscellanous options allowed by 1586 1586 Input Data generic Interface (see \autoref{sec:SBC_input}). 1587 1587 1588 \item [coupled mode]: \NEMO\ and an external wave model can be coupled by setting \np[=.true.]{ln_cpl}{ln\_cpl} 1588 in \nam{sbc}{sbc} namelist and filling the \nam{sbc_cpl}{sbc\_cpl} namelist. 1589 in \nam{sbc}{sbc} namelist and filling the \nam{sbc_cpl}{sbc\_cpl} namelist. NEMO can receive the significant wave height, the mean wave period ($T0M1$), the mean wavenumber, the Charnock parameter, the neutral drag coefficient, the two components of the surface Stokes drift and the associated transport, the wave to ocean momentum flux, the net wave-supported stress, the Bernoulli head $J$ term and the wave to ocean energy flux term. 1589 1590 \end{description} 1591 1590 1592 1591 1593 %% ================================================================================================= … … 1593 1595 \label{subsec:SBC_wave_cdgw} 1594 1596 1595 The neutral surface drag coefficient provided from an external data source (\ie\ awave model),1596 can be used by setting the logical variable \np[=.true.]{ln_cdgw}{ln\_cdgw} in \nam{sbc }{sbc} namelist.1597 Then using the routine \rou{sbcblk\_algo\_ncar} and starting from the neutral drag coeffic ent provided,1597 The neutral surface drag coefficient provided from an external data source (\ie\ forced or coupled wave model), 1598 can be used by setting the logical variable \np[=.true.]{ln_cdgw}{ln\_cdgw} in \nam{sbc_wave}{sbc\_wave} namelist. 1599 Then using the routine \rou{sbcblk\_algo\_ncar} and starting from the neutral drag coefficient provided, 1598 1600 the drag coefficient is computed according to the stable/unstable conditions of the 1599 1601 air-sea interface following \citet{large.yeager_trpt04}. 1600 1601 %% ================================================================================================= 1602 \subsection[3D Stokes Drift (\forcode{ln_sdw} \& \forcode{nn_sdrift})]{3D Stokes Drift (\protect\np{ln_sdw}{ln\_sdw} \& \np{nn_sdrift}{nn\_sdrift})} 1602 %% ================================================================================================= 1603 1604 1605 \subsection[Charnok coefficient from wave model (\forcode{ln_charn})]{ Charnok coefficient from wave model (\protect\np{ln_charn}{ln\_charn})} 1606 \label{subsec:SBC_wave_charn} 1607 1608 The dimensionless Charnock parameter characterising the sea surface roughness provided from an external wave model, can be used by setting the logical variable \np[=.true.]{ln_charn}{ln\_charn} in \nam{sbc_wave}{sbc\_wave} namelist. Then using the routine \rou{sbcblk\_algo\_ecmwf}, the roughness length that enters the definition of the drag coefficient is computed according to the Charnock parameter depending on the sea state. 1609 Note that this option is only available in coupled mode.\\ 1610 1611 %% ================================================================================================= 1612 1613 1614 \subsection[3D Stokes Drift (\forcode{ln_sdw})]{3D Stokes Drift (\protect\np{ln_sdw}{ln\_sdw}) } 1603 1615 \label{subsec:SBC_wave_sdw} 1604 1616 … … 1628 1640 and its computation quickly becomes expensive as the 2D spectrum must be integrated for each vertical level. 1629 1641 To simplify, it is customary to use approximations to the full Stokes profile. 1630 Three possible parameterizations for the calculation for the approximate Stokes drift velocity profile 1631 are included in the code through the \np{nn_sdrift}{nn\_sdrift} parameter once provided the surface Stokes drift 1632 $\mathbf{U}_{st |_{z=0}}$ which is evaluated by an external wave model that accurately reproduces the wave spectra 1633 and makes possible the estimation of the surface Stokes drift for random directional waves in 1634 realistic wave conditions: 1642 Two possible parameterizations for the calculation for the approximate Stokes drift velocity profile 1643 are included in the code once provided the surface Stokes drift $\mathbf{U}_{st |_{z=0}}$ which is evaluated by an external wave model that accurately reproduces the wave spectra and makes possible the estimation of the surface Stokes drift for random directional waves in realistic wave conditions. To evaluate the 3D Stokes drift, the surface Stokes drift (zonal and meridional components), the Stokes transport or alternatively the significant wave height and the mean wave period should be provided either in forced or coupled mode. 1635 1644 1636 1645 \begin{description} 1637 \item [ {\np{nn_sdrift}{nn\_sdrift} = 0}]: exponential integral profile parameterization proposed by1638 \citet{breivik.janssen.ea_JPO14}:1646 \item [By default (\forcode{ln_breivikFV_2016=.true.})]:\\ 1647 An exponential integral profile parameterization proposed by \citet{breivik.janssen.ea_JPO14} is used: 1639 1648 1640 1649 \[ … … 1647 1656 \[ 1648 1657 % \label{eq:SBC_wave_sdw_0b} 1649 k_e = \frac{|\mathbf{U}_{\left.st\right|_{z=0}}|} { |T_{st}|}1658 k_e = \frac{|\mathbf{U}_{\left.st\right|_{z=0}}|} {5.97|T_{st}|} 1650 1659 \quad \text{and }\ 1651 1660 T_{st} = \frac{1}{16} \bar{\omega} H_s^2 1652 1661 \] 1653 1662 1654 where $H_s$ is the significant wave height and $\ omega$ is the wave frequency.1655 1656 \item [ {\np{nn_sdrift}{nn\_sdrift} = 1}]: velocity profile based on the Phillips spectrum which is considered to be a1657 reasonable estimate of the part of the spectrum mostly contributing to the Stokes drift velocity near the surface 1658 \citep{breivik.bidlot.ea_OM16}:1663 where $H_s$ is the significant wave height and $\bar{\omega}$ is the wave frequency defined as: $\bar{\omega}=\frac{2\pi}{T_m}$ (being $T_m$ the mean wave period). 1664 1665 \item [If \forcode{ln_breivikFV_2016= .true.} ]: \\ 1666 1667 A velocity profile based on the Phillips spectrum which is considered to be a reasonable estimate of the part of the spectrum mostly contributing to the Stokes drift velocity near the surface \citep{breivik.bidlot.ea_OM16} is used: 1659 1668 1660 1669 \[ … … 1664 1673 \] 1665 1674 1666 where $erf$ is the complementary error function and $k_p$ is the peak wavenumber. 1667 1668 \item [{\np{nn_sdrift}{nn\_sdrift} = 2}]: velocity profile based on the Phillips spectrum as for \np{nn_sdrift}{nn\_sdrift} = 1 1669 but using the wave frequency from a wave model. 1675 where $erf$ is the complementary error function , $ \beta =1$ and $k_p$ is the peak wavenumber defined as: 1676 \[ 1677 % \label{eq:SBC_wave_kp} 1678 k_p = \frac{|\mathbf{U}_{\left.st\right|_{z=0}}|}{2 |T_{st}| } (1-2 \beta /3) 1679 \] 1680 1681 $|T_{st}|$ is estimated from integral wave parameters (Hs and Tm) in forced mode and is provided directly from an external wave model in coupled mode. 1670 1682 1671 1683 \end{description} 1672 1684 1673 1685 The Stokes drift enters the wave-averaged momentum equation, as well as the tracer advection equations 1674 and its effect on the evolution of the sea-surface height ${\eta}$ is considered as follows: 1675 1676 \[ 1677 % \label{eq:SBC_wave_eta_sdw} 1678 \frac{\partial{\eta}}{\partial{t}} = 1679 -\nabla_h \int_{-H}^{\eta} (\mathbf{U} + \mathbf{U}_{st}) dz 1680 \] 1686 and its effect on the evolution of the sea-surface height ${\eta}$ by including the barotropic Stokes transport horizontal divergence in the term $D$ of Eq.\ref{eq:MB_ssh} 1681 1687 1682 1688 The tracer advection equation is also modified in order for Eulerian ocean models to properly account … … 1699 1705 in a force equal to $\mathbf{U}_{st}$×$f$, where $f$ is the Coriolis parameter. 1700 1706 This additional force may have impact on the Ekman turning of the surface current. 1701 In order to include this term, once evaluated the Stokes drift (using one of the 3possible1707 In order to include this term, once evaluated the Stokes drift (using one of the 2 possible 1702 1708 approximations described in \autoref{subsec:SBC_wave_sdw}), 1703 1709 \np[=.true.]{ln_stcor}{ln\_stcor} has to be set. 1704 1710 1705 1711 %% ================================================================================================= 1706 \subsection[Wave modified stress (\forcode{ln_tauwoc} \& \forcode{ln_tauw})]{Wave modified sress (\protect\np{ln_tauwoc}{ln\_tauwoc} \& \np{ln_tauw}{ln\_tauw})} 1707 \label{subsec:SBC_wave_tauw} 1712 1713 %% ================================================================================================= 1714 \subsection[Vortex-force term (\forcode{ln_vortex_force})]{Vortex-force term (\protect\np{ln_vortex_force}{ln\_vortex\_force})} 1715 \label{subsec:SBC_wave_vf} 1716 1717 The vortex-force term arises from the interaction of the mean flow vorticity with the Stokes drift. 1718 It results in a force equal to $\mathbf{U}_{st}$×$\zeta$, where $\zeta$ is the mean flow vorticity. 1719 In order to include this term, once evaluated the Stokes drift (using one of the 2 possible 1720 approximations described in \autoref{subsec:SBC_wave_sdw}), \np[=.true.]{ln_vortex_force}{ln\_vortex\_force} has to be set. 1721 1722 %% ================================================================================================= 1723 1724 %% ================================================================================================= 1725 \subsection[Wave-induced pressure term (\forcode{ln_bern_srfc})]{ Wave-induced pressure term (\protect\np{ln_bern_srfc}{ln\_bern\_srfc})} 1726 \label{subsec:SBC_wave_bhd} 1727 An adjustment in the mean pressure arises to accommodate for the presence of waves. 1728 The mean pressure is corrected adding a depth-uniform wave-induced kinematic pressure term named Bernoulli head $J$ term. The Bernoulli head $J$ term is provided to NEMO from an external wave model where it is defined as: 1729 \[ 1730 % \label{eq:SBC_wave_tauw} 1731 J = g \iint {\frac{k}{sinh(2kd)} S(k,\theta) d\theta dk} 1732 \] 1733 with $d$ the water depth. \\ 1734 In order to include this term, \np[=.true.]{ln_bern_srfc}{ln\_bern\_srfc} has to be defined as well as the Stokes drift option (\autoref{subsec:SBC_wave_sdw}) and the coupling with an external wave model (\autoref{sec:SBC_wave}). 1735 1736 %% ================================================================================================= 1737 1738 1739 \subsection[Wave modified stress (\forcode{ln_tauoc} \& \forcode{ln_taw})]{Wave modified stress (\protect\np{ln_tauoc}{ln\_tauoc} \& \np{ln_taw}{ln\_taw})} 1740 \label{subsec:SBC_wave_taw} 1708 1741 1709 1742 The surface stress felt by the ocean is the atmospheric stress minus the net stress going … … 1720 1753 \] 1721 1754 1722 where $\tau_a$ is the atmospheric surface stress; 1723 $\tau_w$ is the atmospheric stress going into the waves defined as: 1755 where $\tau_a$ is the atmospheric surface stress; $\tau_w$ is the atmospheric stress going into the waves defined as: 1724 1756 1725 1757 \[ 1726 1758 % \label{eq:SBC_wave_tauw} 1727 \tau_w = \rho g \int {\frac{dk}{c_p} (S_{in}+S_{nl}+S_{diss})}1759 \tau_w = \rho g \int_{0}^{2\pi} \int {\frac{1}{c_p} (S_{in}+S_{nl}+S_{diss})}dkd\theta 1728 1760 \] 1761 1762 %% ∫2π0∫∞0kω(Sin+Sds) dωdθ 1729 1763 1730 1764 where: $c_p$ is the phase speed of the gravity waves, 1731 1765 $S_{in}$, $S_{nl}$ and $S_{diss}$ are three source terms that represent 1732 the physics of ocean waves. The first one, $S_{in}$, describes the generation 1733 of ocean waves by wind and therefore represents the momentum and energy transfer 1734 from air to ocean waves; the second term $S_{nl}$ denotes 1735 the nonlinear transfer by resonant four-wave interactions; while the third term $S_{diss}$ 1736 describes the dissipation of waves by processes such as white-capping, large scale breaking 1737 eddy-induced damping. 1738 1739 The wave stress derived from an external wave model can be provided either through the normalized 1740 wave stress into the ocean by setting \np[=.true.]{ln_tauwoc}{ln\_tauwoc}, or through the zonal and 1741 meridional stress components by setting \np[=.true.]{ln_tauw}{ln\_tauw}. 1766 the physics of ocean waves. The first one, $S_{in}$, describes the generation of ocean waves by wind and therefore represents the momentum and energy transfer from air to ocean waves; the second term $S_{nl}$ denotes 1767 the nonlinear transfer by resonant four-wave interactions; while the third term $S_{diss}$ describes the dissipation of waves by processes such as white-capping, large scale breaking eddy-induced damping. Note that the $S_{nl}$ is not always taken into account for the calculation of the atmospheric stress going into the waves, depending on the external wave model. 1768 The wave stress derived from an external wave model can be provided either through the normalized wave stress into the ocean by setting \np[=.true.]{ln_tauoc}{ln\_tauoc}, or through the zonal and meridional stress components by setting 1769 \np[=.true.]{ln_taw}{ln\_taw} . In coupled mode both options can be used while in forced mode only the first option is included. 1770 1771 If the normalized wave stress into the ocean ($\widetilde{\tau}$) is provided (\np[=.true.]{ln_tauoc}{ln\_tauoc}) the atmospheric stress felt by the ocean circulation is expressed as: 1772 \[ 1773 % \label{eq:SBC_wave_tauoc} 1774 \tau_{oc,a} = \tau_a \times \widetilde{\tau} 1775 \] 1776 1777 If \np[=.true.]{ln_taw}{ln\_taw} , the zonal and meridional stress fields components from the coupled wave model have to be sent directly to u-grid and v-grid through OASIS. 1778 1779 1780 %% ================================================================================================= 1781 1782 \subsection[Waves impact vertical mixing (\forcode{ln_phioc} \& \forcode{ln_stshear})]{Waves impact vertical mixing (\protect\np{ln_phioc}{ln\_phioc} \& \protect\np{ln_stshear}{ln\_stshear})} 1783 \label{subsec:SBC_wave_TKE} 1784 1785 1786 The vortex-force vertical term gives rise to extra terms in the turbulent kinetic energy (TKE) prognostic \citep{couvelard_2020}. The first term corresponds to a modification of the shear production term. 1787 The Stokes Drift shear contribution can be included, in coupled mode, by setting \np[=.true.]{ln_stshear}{ln\_stshear}. 1788 1789 1790 In addition, waves affect the surface boundary condition for the turbulent kinetic energy, the mixing length scale and the dissipative length scale of the TKE closure scheme. 1791 The injection of turbulent kinetic energy at the surface can be given by the dissipation of the wave field usually dominated by wave breaking. 1792 1793 In coupled mode, the wave to ocean energy flux term from an external wave model ($ \Phi_o $) can be provided to NEMO and then converted into an ocean turbulence source by setting \np[=.true.]{ln_phioc}{ln\_phioc}. 1794 The boundary condition for the turbulent kinetic energy is implemented in the \rou{zdftke} as a Dirichlet or as a Neumann boundary condition (see \autoref{subsubsec:ZDF_tke_waveco}). The boundary condition for the mixing length scale and the dissipative length scale can also account for surface waves (see \autoref{subsubsec:ZDF_tke_waveco}) 1795 1796 Some improvements are introduced in the Langmuir turbulence parameterization (see \autoref{chap:ZDF} \autoref{subsubsec:ZDF_tke_langmuir}) if wave coupled mode is activated. 1742 1797 1743 1798 %% ================================================================================================= -
NEMO/trunk/doc/latex/NEMO/subfiles/chap_ZDF.tex
r14530 r15522 278 278 279 279 %% ================================================================================================= 280 \subsubsection{Surface wave breaking parameterization} 280 \subsubsection{Surface wave breaking parameterization (No information from an external wave model)} 281 \label{subsubsec:ZDF_tke_wave} 281 282 282 283 Following \citet{mellor.blumberg_JPO04}, the TKE turbulence closure model has been modified to … … 306 307 with $e_{bb}$ the \np{rn_ebb}{rn\_ebb} namelist parameter, setting \np[=67.83]{rn_ebb}{rn\_ebb} corresponds 307 308 to $\alpha_{CB} = 100$. 308 Further setting \np[=.true.]{ln_mxl0}{ln\_mxl0}, applies \autoref{eq:ZDF_Lsbc} as the surface boundary condition on the length scale, 309 with $\beta$ hard coded to the Stacey's value. 310 Note that a minimal threshold of \np{rn_emin0}{rn\_emin0}$=10^{-4}~m^2.s^{-2}$ (namelist parameters) is applied on the 311 surface $\bar{e}$ value. 309 310 Further setting \np[=.true.]{ln_mxl0}{ln\_mxl0}, applies \autoref{eq:ZDF_Lsbc} as the surface boundary condition on the length scale, with $\beta$ hard coded to the Stacey's value. Note that a minimal threshold of \np{rn_emin0}{rn\_emin0}$=10^{-4}~m^2.s^{-2}$ (namelist parameters) is applied on the surface $\bar{e}$ value.\\ 311 312 \subsubsection{Surface wave breaking parameterization (using information from an external wave model)} 313 \label{subsubsec:ZDF_tke_waveco} 314 315 Surface boundary conditions for the turbulent kinetic energy, the mixing length scale and the dissipative length scale can be defined using wave fields provided from an external wave model (see \autoref{chap:SBC}, \autoref{sec:SBC_wave}). 316 The injection of turbulent kinetic energy at the surface can be given by the dissipation of the wave field usually dominated by wave breaking. In coupled mode, the wave to ocean energy flux term ($\Phi_o$) from an external wave model can be provided and then converted into an ocean turbulence source by setting ln\_phioc=.true. 317 318 The surface TKE can be defined by a Dirichlet boundary condition setting $nn\_bc\_surf=0$ in \nam{zdf}{tke} namelist: 319 \begin{equation} 320 \bar{e}_o = \frac{1}{2}\,\left( 15.8 \, \frac{\Phi_o}{\rho_o}\right) ^{2/3} 321 \end{equation} 322 323 Nevertheless, due to the definition of the computational grid, the TKE flux is not applied at the free surface but at the centre of the topmost grid cell ($z = z1$). To be more accurate, a Neumann boundary condition amounting to interpreter the half-grid cell at the top as a constant flux layer (consistent with the surface layer Monin–Obukhov theory) can be applied setting $nn\_bc\_surf=1$ in \nam{zdf}{tke} namelist \citep{couvelard_2020}: 324 325 \begin{equation} 326 \left(\frac{Km}{e_3}\,\partial_k e \right)_{z=z1} = \frac{\Phi_o}{\rho_o} 327 \end{equation} 328 329 330 The mixing length scale surface value $l_0$ can be estimated from the surface roughness length z0: 331 \begin{equation} 332 l_o = \kappa \, \frac{ \left( C_k\,C_\epsilon \right) ^{1/4}}{C_k}\, z0 333 \end{equation} 334 where $z0$ is directly estimated from the significant wave height ($Hs$) provided by the external wave model as $z0=1.6Hs$. To use this option ln\_mxhsw as well as ln\_wave and ln\_sdw have to be set to .true. 312 335 313 336 %% ================================================================================================= 314 337 \subsubsection{Langmuir cells} 338 \label{subsubsec:ZDF_tke_langmuir} 315 339 316 340 Langmuir circulations (LC) can be described as ordered large-scale vertical motions in … … 335 359 \] 336 360 where $w_{LC}(z)$ is the vertical velocity profile of LC, and $H_{LC}$ is the LC depth. 337 With no information about the wave field, $w_{LC}$ is assumed to be proportional to 338 the Stokes drift $u_s = 0.377\,\,|\tau|^{1/2}$, where $|\tau|$ is the surface wind stress module 339 \footnote{Following \citet{li.garrett_JMR93}, the surface Stoke drift velocity may be expressed as 340 $u_s = 0.016 \,|U_{10m}|$. 341 Assuming an air density of $\rho_a=1.22 \,Kg/m^3$ and a drag coefficient of 342 $1.5~10^{-3}$ give the expression used of $u_s$ as a function of the module of surface stress 343 }. 361 344 362 For the vertical variation, $w_{LC}$ is assumed to be zero at the surface as well as at 345 363 a finite depth $H_{LC}$ (which is often close to the mixed layer depth), … … 349 367 w_{LC} = 350 368 \begin{cases} 351 c_{LC} \, u_s\,\sin(- \pi\,z / H_{LC} ) & \text{if $-z \leq H_{LC}$} \\369 c_{LC} \,\|u_s^{LC}\| \,\sin(- \pi\,z / H_{LC} ) & \text{if $-z \leq H_{LC}$} \\ 352 370 0 & \text{otherwise} 353 371 \end{cases} 354 372 \] 355 where $c_{LC} = 0.15$ has been chosen by \citep{axell_JGR02} as a good compromise to fit LES data. 356 The chosen value yields maximum vertical velocities $w_{LC}$ of the order of a few centimeters per second. 373 374 375 In the absence of information about the wave field, $w_{LC}$ is assumed to be proportional to 376 the surface Stokes drift ($u_s^{LC}=u_{s0} $) empirically estimated by $ u_{s0} = 0.377\,\,|\tau|^{1/2}$, where $|\tau|$ is the surface wind stress module 377 \footnote{Following \citet{li.garrett_JMR93}, the surface Stoke drift velocity may be expressed as 378 $u_{s0} = 0.016 \,|U_{10m}|$. 379 Assuming an air density of $\rho_a=1.22 \,Kg/m^3$ and a drag coefficient of 380 $1.5~10^{-3}$ give the expression used of $u_{s0}$ as a function of the module of surface stress 381 }. 382 383 In case of online coupling with an external wave model (see \autoref{chap:SBC} \autoref{sec:SBC_wave}), $w_{LC}$ is proportional to the component of the Stokes drift aligned with the wind \citep{couvelard_2020} and $ u_s^{LC} = \max(u_{s0}.e_\tau,0)$ where $e_\tau$ is the unit vector in the wind stress direction and $u_{s0}$ is the surface Stokes drift provided by the external wave model. 384 385 386 $c_{LC} = 0.15$ has been chosen by \citep{axell_JGR02} as a good compromise to fit LES data. 387 The chosen value yields maximum vertical velocities $w_{LC}$ of the order of a few centimetres per second. 357 388 The value of $c_{LC}$ is set through the \np{rn_lc}{rn\_lc} namelist parameter, 358 389 having in mind that it should stay between 0.15 and 0.54 \citep{axell_JGR02}. … … 362 393 converting its kinetic energy to potential energy, according to 363 394 \[ 364 - \int_{-H_{LC}}^0 { N^2\;z \;dz} = \frac{1}{2} u_s^2395 - \int_{-H_{LC}}^0 { N^2\;z \;dz} = \frac{1}{2} \|u_s^{LC}\|^2 365 396 \] 366 397 … … 1427 1458 the Stokes Drift can be evaluated by setting \forcode{ln_sdw=.true.} 1428 1459 (see \autoref{subsec:SBC_wave_sdw}) 1429 and the needed wave fields can be provided either in forcing or coupled mode1460 and the needed wave fields (significant wave height and mean wave number) can be provided either in forcing or coupled mode 1430 1461 (for more information on wave parameters and settings see \autoref{sec:SBC_wave}) 1431 1462 -
NEMO/trunk/doc/namelists/namsbc
r11005 r15522 33 33 ln_isf = .false. ! ice shelf (T => fill namsbc_isf & namsbc_iscpl) 34 34 ln_wave = .false. ! Activate coupling with wave (T => fill namsbc_wave) 35 ln_cdgw = .false. ! Neutral drag coefficient read from wave model (T => ln_wave=.true. & fill namsbc_wave)36 ln_sdw = .false. ! Read 2D Surf Stokes Drift & Computation of 3D stokes drift (T => ln_wave=.true. & fill namsbc_wave)37 nn_sdrift = 0 ! Parameterization for the calculation of 3D-Stokes drift from the surface Stokes drift38 ! ! = 0 Breivik 2015 parameterization: v_z=v_0*[exp(2*k*z)/(1-8*k*z)]39 ! ! = 1 Phillips: v_z=v_o*[exp(2*k*z)-beta*sqrt(-2*k*pi*z)*erfc(sqrt(-2*k*z))]40 ! ! = 2 Phillips as (1) but using the wave frequency from a wave model41 ln_tauwoc = .false. ! Activate ocean stress modified by external wave induced stress (T => ln_wave=.true. & fill namsbc_wave)42 ln_tauw = .false. ! Activate ocean stress components from wave model43 ln_stcor = .false. ! Activate Stokes Coriolis term (T => ln_wave=.true. & ln_sdw=.true. & fill namsbc_wave)44 35 nn_lsm = 0 ! =0 land/sea mask for input fields is not applied (keep empty land/sea mask filename field) , 45 36 ! =1:n number of iterations of land/sea mask application for input fields (fill land/sea mask filename field) -
NEMO/trunk/doc/namelists/namsbc_cpl
r13472 r15522 48 48 sn_rcv_isf = 'none' , 'no' , '' , '' , '' 49 49 sn_rcv_icb = 'none' , 'no' , '' , '' , '' 50 sn_rcv_tauwoc = 'none' , 'no' , '' , '' , '' 51 sn_rcv_tauw = 'none' , 'no' , '' , '' , '' 52 sn_rcv_wdrag = 'none' , 'no' , '' , '' , '' 50 sn_rcv_wdrag = 'none' , 'no' , '' , '' , '' 51 sn_rcv_charn = 'none' , 'no' , '' , '' , '' 52 sn_rcv_taw = 'none' , 'no' , '' , '' , 'U,V' 53 sn_rcv_bhd = 'none' , 'no' , '' , '' , '' 54 sn_rcv_tusd = 'none' , 'no' , '' , '' , '' 55 sn_rcv_tvsd = 'none' , 'no' , '' , '' , '' 53 56 / -
NEMO/trunk/doc/namelists/namsbc_wave
r11703 r15522 2 2 &namsbc_wave ! External fields from wave model (ln_wave=T) 3 3 !----------------------------------------------------------------------- 4 ln_sdw = .false. ! get the 2D Surf Stokes Drift & Compute the 3D stokes drift 5 ln_stcor = .false. ! add Stokes Coriolis and tracer advection terms 6 ln_cdgw = .false. ! Neutral drag coefficient read from wave model 7 ln_tauoc = .false. ! ocean stress is modified by wave induced stress 8 ln_wave_test= .false. ! Test case with constant wave fields 9 ! 10 ln_charn = .false. ! Charnock coefficient read from wave model (IFS only) 11 ln_taw = .false. ! ocean stress is modified by wave induced stress (coupled mode) 12 ln_phioc = .false. ! TKE flux from wave model 13 ln_bern_srfc= .false. ! wave induced pressure. Bernoulli head J term 14 ln_breivikFV_2016 = .false. ! breivik 2016 vertical stokes profile 15 ln_vortex_force = .false. ! Vortex Force term 16 ln_stshear = .false. ! include stokes shear in EKE computation 17 ! 4 18 cn_dir = './' ! root directory for the waves data location 5 19 !___________!_________________________!___________________!___________!_____________!________!___________!__________________!__________!_______________! … … 11 25 sn_hsw = 'sdw_ecwaves_orca2' , 6. , 'hs' , .true. , .true. , 'yearly' , '' , '' , '' 12 26 sn_wmp = 'sdw_ecwaves_orca2' , 6. , 'wmp' , .true. , .true. , 'yearly' , '' , '' , '' 13 sn_wfr = 'sdw_ecwaves_orca2' , 6. , 'wfr' , .true. , .true. , 'yearly' , '' , '' , ''14 27 sn_wnum = 'sdw_ecwaves_orca2' , 6. , 'wave_num' , .true. , .true. , 'yearly' , '' , '' , '' 15 sn_tauwoc = 'sdw_ecwaves_orca2' , 6. , 'wave_stress', .true. , .true. , 'yearly' , '' , '' , '' 16 sn_tauwx = 'sdw_ecwaves_orca2' , 6. , 'wave_stress', .true. , .true. , 'yearly' , '' , '' , '' 17 sn_tauwy = 'sdw_ecwaves_orca2' , 6. , 'wave_stress', .true. , .true. , 'yearly' , '' , '' , '' 28 sn_tauoc = 'sdw_ecwaves_orca2' , 6. , 'wave_stress', .true. , .true. , 'yearly' , '' , '' , '' 18 29 / -
NEMO/trunk/doc/namelists/namzdf_tke
r13472 r15522 30 30 ! ! = 2 weighted by 1-fr_i 31 31 ! ! = 3 weighted by 1-MIN(1,4*fr_i) 32 nn_bc_surf = 1 ! surface condition (0/1=Dir/Neum) ! Only applicable for wave coupling (ln_cplwave=1) 33 nn_bc_bot = 1 ! bottom condition (0/1=Dir/Neum) ! Only applicable for wave coupling (ln_cplwave=1) 32 34 /
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