Changeset 10613 for NEMO/releases/release-4.0/doc/latex/NEMO/subfiles/chap_SBC.tex

Timestamp:

2019-01-31T17:38:13+01:00 (4 years ago)

Author:

smueller

Message:

Revision of two subsections on tidal forcing and update of the list of NEMO System Team members in the NEMO manual

File:

• NEMO/releases/release-4.0/doc/latex/NEMO/subfiles/chap_SBC.tex (modified) (2 diffs)

NEMO/releases/release-4.0/doc/latex/NEMO/subfiles/chap_SBC.tex

@@ -815 +815 @@
 
 The tidal forcing, generated by the gravity forces of the Earth-Moon and Earth-Sun sytems,
-is activated if \np{ln\_tide} and \np{ln\_tide\_pot} are both set to \np{.true.} in \ngn{nam\_tide}.
+is activated if \np{ln\_tide} and \np{ln\_tide\_pot} are both set to \forcode{.true.} in \ngn{nam\_tide}.
 This translates as an additional barotropic force in the momentum equations \ref{eq:PE_dyn} such that:
 \[
@@ -822 +822 @@
   +g\nabla (\Pi_{eq} + \Pi_{sal})
 \]
-where $\Pi_{eq}$ stands for the equilibrium tidal forcing and $\Pi_{sal}$ a self-attraction and loading term (SAL). 
+where $\Pi_{eq}$ stands for the equilibrium tidal forcing and
+$\Pi_{sal}$ is a self-attraction and loading term (SAL).
  
-The equilibrium tidal forcing is expressed as a sum over the chosen constituents $l$ in \ngn{nam\_tide}.
-The constituents are defined such that \np{clname(1) = 'M2', clname(2)='S2', etc...}.
-For the three types of tidal frequencies it reads: \\
-Long period tides :
-\[
-  \Pi_{eq}(l)=A_{l}(1+k-h)(\frac{1}{2}-\frac{3}{2}sin^{2}\phi)cos(\omega_{l}t+V_{l})
-\]
-diurnal tides :
-\[
-  \Pi_{eq}(l)=A_{l}(1+k-h)(sin 2\phi)cos(\omega_{l}t+\lambda+V_{l})
-\]
-Semi-diurnal tides:
-\[
-  \Pi_{eq}(l)=A_{l}(1+k-h)(cos^{2}\phi)cos(\omega_{l}t+2\lambda+V_{l})
-\]
-Here $A_{l}$ is the amplitude, $\omega_{l}$ is the frequency, $\phi$ the latitude, $\lambda$ the longitude,
-$V_{0l}$ a phase shift with respect to Greenwich meridian and $t$ the time.
-The Love number factor $(1+k-h)$ is here taken as a constant (0.7).
-
-The SAL term should in principle be computed online as it depends on the model tidal prediction itself
-(see \citet{Arbic2004} for a discussion about the practical implementation of this term).
-Nevertheless, the complex calculations involved would make this computationally too expensive.
-Here, practical solutions are whether to read complex estimates $\Pi_{sal}(l)$ from an external model
-(\np{ln\_read\_load=.true.}) or use a ``scalar approximation'' (\np{ln\_scal\_load=.true.}).
-In the latter case, it reads:\\
-\[
-  \Pi_{sal} = \beta \eta
-\]
-where $\beta$ (\np{rn\_scal\_load}, $\approx0.09$) is a spatially constant scalar,
-often chosen to minimize tidal prediction errors.
-Setting both \np{ln\_read\_load} and \np{ln\_scal\_load} to false removes the SAL contribution.
+The equilibrium tidal forcing is expressed as a sum over a subset of
+constituents chosen from the set of available tidal constituents
+defined in file \rou{SBC/tide.h90} (this comprises the tidal
+constituents \textit{M2, N2, 2N2, S2, K2, K1, O1, Q1, P1, M4, Mf, Mm,
+  Msqm, Mtm, S1, MU2, NU2, L2}, and \textit{T2}). Individual
+constituents are selected by including their names in the array
+\np{clname} in \ngn{nam\_tide} (e.g., \np{clname(1) = 'M2',
+  clname(2)='S2'} to select solely the tidal consituents \textit{M2}
+and \textit{S2}). Optionally, when \np{ln\_tide\_ramp} is set to
+\forcode{.true.}, the equilibrium tidal forcing can be ramped up
+linearly from zero during the initial \np{rdttideramp} days of the
+model run.
+
+The SAL term should in principle be computed online as it depends on
+the model tidal prediction itself (see \citet{Arbic2004} for a
+discussion about the practical implementation of this term).
+Nevertheless, the complex calculations involved would make this
+computationally too expensive.  Here, two options are available:
+$\Pi_{sal}$ generated by an external model can be read in
+(\np{ln\_read\_load=.true.}), or a ``scalar approximation'' can be
+used (\np{ln\_scal\_load=.true.}). In the latter case
+\[
+  \Pi_{sal} = \beta \eta,
+\]
+where $\beta$ (\np{rn\_scal\_load} with a default value of 0.094) is a
+spatially constant scalar, often chosen to minimize tidal prediction
+errors. Setting both \np{ln\_read\_load} and \np{ln\_scal\_load} to
+\forcode{.false.} removes the SAL contribution.
 
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