source: trunk/LMDZ.MARS/doc/utilities.tex @ 3493

Last change on this file since 3493 was 1954, checked in by emillour, 7 years ago

Mars GCM:

  • Make a "doc" subdirectory to store the documentation source files with the code.

EM

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1\chapter{Utilities}
2
3\label{sc:utilities}
4
5A few post-processing tools, which handle GCM outputs (files
6{\tt diagfi.nc} and {\tt stats.nc}) are available in the
7{\tt LMDZ.MARS/util} subdirectory.
8This directory contains the sources codes along with a {\tt README.exec}
9file which explains what the various programs are for and
10how to compile them.
11
12\section{concatnc}
13This program concatenates consecutive
14output files ({\tt diagfi.nc} or even {\tt stats.nc} files) for a selection of
15variable, in order to obtain one single big file.
16The time dimension of the output can
17be "sols" or "Ls" (note that in that latter case, Ls values won't be
18evenly distributed, and
19software like Grads may not be able to use and plot the data).\\
20To obtain an evenly sampled "Ls"
21timescale, you can use the {\tt lslin.e} program (described below).\\
22The output file created by {\tt conctanc.e} is {\tt concat.nc}
23
24\section{lslin}
25
26This program is designed to interpolate data given
27in  irregular Solar Longitude (Ls) into an evenly sampled
28linear time coordinate (usable with Grads).
29Input Netcdf files may be {\tt diagfi.nc} or {\tt concat.nc} 
30files and the resulting
31output file is {\tt lslin.nc}
32lslin also create a {\tt lslin.ctl} file that can be read
33directly by grads (\verb+>xdfopen lslin.ctl+) to plot in Ls coordinate to
34avoid some problem with grads when Grads think that "the time interval
35is too small"...
36
37\section{localtime}
38
39The {\tt localtime.e} program is designed to re-interpolate data in order
40to yield values at the same given local time (useful to mimic satellite
41observations, or analyse day to day variations at given local time).\\
42Input files may be of {\tt diagfi.nc}, {\tt stats.nc} or {\tt concat.nc}
43type and the output file name is build from the input one, to which
44{\tt \_LT.nc} is appened (e.g. if the input file is {\tt myfile.nc} then
45output file will be {\tt myfile\_LT.nc}).
46
47\section{zrecast}
48With this program you can recast atmospheric (i.e.: 4D-dimentional
49longitude-latitude-altitude-time) data from GCM outputs (e.g. as given in
50{\tt diagfi.nc}, {\tt concat.nc} and {\tt stats.nc} files) onto
51either {\it pressure} or {\it altitude above areoid} vertical coordinates.\\
52Since integrating the hydrostatic equation is required to recast the data,
53the input file must contain surface pressure and atmospheric temperature,
54as well as the ground geopotential.\\
55If recasting data onto {\it pressure} coordinates, then the output file name
56is given by the input file name to which {\tt\_P.nc} will be appened.
57If recasting data onto {\it altitude above areoid} coordinates, then a
58{\tt\_A.nc} will be appened.
59
60\section{hrecast}
61This program can interpolate GCM output on any horizontal grid
62(regular lat - lon) as long as it cover all the
63planet. Useful to compare runs obtained at different horizontal resolutions.
64
65\section{expandstartfi}
66This program takes a physics start file ({\tt startfi.nc}) and recasts it
67on the corresponding  lonxlat grid (so its contents may easily be displayed
68using Grads, Ferret, etc.)
69
70\section{extract}
71This program extracts (ie: interpolates) pointwise values of an atmospheric
72variable from a 'zrecast'ed diagfi file (works if altitude is geometrical
73height or a pressure vertical coordinates).
74
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