1 |
|
2 |
%\subsubsection{File {\it input/data.shap}} |
3 |
%\label{www:tutorials} |
4 |
|
5 |
This file, reproduced completely below, specifies the parameters |
6 |
that the model uses for the Shapiro filter package (\cite{Shapiro_70}, |
7 |
section \ref{sec:shapiro-filter}). |
8 |
The parameters that are significant for this configuration are: |
9 |
|
10 |
\begin{itemize} |
11 |
|
12 |
\item Line PUT_LINE_NB:Shap_funct=, |
13 |
\begin{verbatim} |
14 |
Shap_funct=2, |
15 |
\end{verbatim} |
16 |
This line selects the shapiro filter function |
17 |
to use, here S2 in this experiment |
18 |
(see section \ref{sec:shapiro-filter}). |
19 |
|
20 |
\item Lines PUT_LINE_NB:nShapT= and PUT_LINE_NB:nShapUV=, |
21 |
\begin{verbatim} |
22 |
nShapT=0, |
23 |
nShapUV=4, |
24 |
\end{verbatim} |
25 |
Those lines select the order of the shapiro filter |
26 |
for active tracer ($\theta$ and $q$) and momentum ($u,v$) respectively. |
27 |
In this case, no filter is applied to active tracers. Regarding |
28 |
the momentum, this sets the integer parameter $n$ to 4, in the equations of |
29 |
section \ref{sec:shapiro-filter}, which corresponds to a 8th order |
30 |
filter. |
31 |
|
32 |
\item Line PUT_LINE_NB:nShapUVPhys=, |
33 |
\begin{verbatim} |
34 |
nShapUVPhys=4, |
35 |
\end{verbatim} |
36 |
This line selects the order of the physical space filter |
37 |
(filter function S2g, in section \ref{sec:shapiro-filter}) |
38 |
that applies to $u,v$. |
39 |
The difference {\it nShapUV - nShapUVPhys} |
40 |
corresponds to the order of the computational filter |
41 |
(filter function S2c, in section \ref{sec:shapiro-filter}). |
42 |
|
43 |
\item Lines PUT_LINE_NB:#Shap_Trtau= and PUT_LINE_NB:#Shap_uvtau=, |
44 |
\begin{verbatim} |
45 |
#Shap_Trtau=5400., |
46 |
#Shap_uvtau=1800., |
47 |
\end{verbatim} |
48 |
Those commented lines would have set the time scale of the filter (in seconds), |
49 |
for $\theta$ and $q$ and for $u$ and $v$ respectively, |
50 |
to 5400 s (90 min) and 1800 s (30 min) respectively. |
51 |
Without explicitly setting those timescales, the default is used |
52 |
which corresponds to the model time-step. |
53 |
%Note that a shorter time scale means a stronger filter, and |
54 |
%that the time scale cannot be smaller than the time-step $\Delta t$ |
55 |
%of the model. |
56 |
|
57 |
\end{itemize} |
58 |
|
59 |
The entire file {\it input/data.shap} is reproduced here below: |
60 |
|
61 |
\begin{small} |
62 |
\input{s_examples/held_suarez_cs/input/data.shap} |
63 |
\end{small} |