Changeset 2990 for branches/2011/dev_r2855_INGV2_3_blk_wave/DOC/TexFiles/Chapters/Chap_ZDF.tex

Timestamp:

2011-10-25T15:39:07+02:00 (13 years ago)

Author:

poddo

Message:

Development DEV2011_INGV2_bulk ECMWF bulk formulae
merged with
Development DEV2011_INGV3_wave Interface to read neutral drag coefficient from wave model

File:

• branches/2011/dev_r2855_INGV2_3_blk_wave/DOC/TexFiles/Chapters/Chap_ZDF.tex (modified) (1 diff)

branches/2011/dev_r2855_INGV2_3_blk_wave/DOC/TexFiles/Chapters/Chap_ZDF.tex

@@ -100 +100 @@
 $a=5$ and $n=2$. The last three values can be modified by setting the 
 \np{rn\_avmri}, \np{rn\_alp} and \np{nn\_ric} namelist parameters, respectively.
+
+A simple mixing-layer model to transfer and dissipate the atmospheric
+ forcings (wind-stress and buoyancy fluxes) can be activated setting 
+the \np{ln\_mldw} =.true. in the namelist.
+
+In this case, the local depth of turbulent wind-mixing or "Ekman depth"
+ $h_{e}(x,y,t)$ is evaluated and the vertical eddy coefficients prescribed within this layer.
+
+This depth is assumed proportional to the "depth of frictional influence" that is limited by rotation:
+\begin{equation}
+         h_{e} = Ek \frac {u^{*}} {f_{0}}    \\
+\end{equation}
+where, $Ek$ is an empirical parameter, $u^{*}$ is the friction velocity and $f_{0}$ is the Coriolis 
+parameter.
+
+In this similarity height relationship, the turbulent friction velocity:
+\begin{equation}
+         u^{*} = \sqrt \frac {|\tau|} {\rho_o}     \\
+\end{equation}
+
+is computed from the wind stress vector $|\tau|$ and the reference dendity $ \rho_o$.
+The final $h_{e}$ is further constrained by the adjustable bounds \np{rn\_mldmin} and \np{rn\_mldmax}.
+Once $h_{e}$ is computed, the vertical eddy coefficients within $h_{e}$ are set to 
+the empirical values \np{rn\_wtmix} and \np{rn\_wvmix} \citep{Lermusiaux2001}.
 
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