Subversion Repositories lagranto.ecmwf

1. Code retrieval
------------------

Download the latest Lagranto version from SVN repository <https://svn.iac.ethz.ch/websvn/pub/wsvn/>.

Then create a directory where you want Lagranto to be installed; place the whole source code in this
directory and set an environment variable {LAGRANTO} pointing to this directory.

> setenv LAGRANTO {PATH TO YOUR LAGRANTO INSTALLATION}


2. Compiling the Lagranto code
-------------------------------

Choose the correct Fortran compiler in <install.csh>. At the moment, PGI is set. I have sucessfully 
compiled the code with <ifort> and <gfortran>, so you might want to use one of these two compilers.
You additonally have to set in <install.csh> the environment variable <NETCDF> which point to the
installstion of the netCDF libraries.

> setenv NETCDF  {PATH TO YOUR NETCDF LIBRARY}

> cd ${LAGRANTO}/
> ./install.csh clean
> ./install.csh lib
> ./install.csh create_startf
> ./install.csh caltra
> ./install.csh trace
> ./install.csh select
> ./install.csh density
> ./install.csh lidar
> ./install.csh goodies
> ./install.csh docu
> ./install.csh links

Add the end of the installation, it's best to add the following directory to your PATH variable. In <bash> 
this should look like

>  export PATH=${LAGRANTO}/bin/:$PATH

If the <LAGRANTO/bin> directory is in your PATH, then you will be able to run Lagranto from any directory. 
Otherwise, you will always to give the full path to your Lagranto commands, e.g.

> ${LAGRANTO}/bin/caltra



3. Compiling the Grib-netCDF converter
--------------------------------------

In the subdirectory <convert/fgrb2cdf> you find the program you find the Fortran program which we use to
convert the Grib files from ECMWF into netCDF. Note that we use a somewhat 'strange' netCDF format; therefore
you have to use this converter. In the near future, I will make available a conversion tool based on the CDO
tools...

You will have to set some paths to compile the program; in particular, a reference must be made to the
GRIB_API.


4. Lagranto documentation
-------------------------

Lagranto comes with a detailed documentation; you can start it with one of the following calls:

> lagrantohelp
> lagrantohelp tutorial
> lagrantohelp reference

The most important program for you will be <caltra> which calculates the trajectories...

> lagrantohelp caltra


5. Test data set
-----------------

On our FTP server you find a sample data set which allows you to run Lagranto without bothering about the
Grib-netCDF conversion.

ftp://iacftp.ethz.ch/pub_read/sprenger/lagranto.ecmwf.test/


6. Minimal test run
--------------------

a) Define a starting position in a file <startf>; the format is <longitude latitude pressure>.

> more startf
  8.0 46.0 500.
-10.0 30.0 850.

Each line corresponds to a single starting position. Note that longitudes must be within -180 ... +180 deg.


b) Start the trajectory

It is a forward trajectory starting at 00 UTC 1 Jan 2012. The time span is 18 UTC. Starting positions are
taken from <startf>, the output is written to <trajectory>. For details about the optional flag <-j> and
<-notimecheck>, please consult the Lagranto help <lagrantohelp caltra>.

> caltra 20120101_00 20120101_18 startf trajectory -j
> more trajectory
Reference date 20120101_0000 / Time range    1080 min

  time      lon     lat     p
-----------------------------

    .00     8.00   46.00   500
   6.00    10.02   44.07   480
  12.00    11.64   42.13   504
  18.00    12.66   40.17   514

    .00   -10.00   30.00   850
   6.00   -10.42   30.14   866
  12.00   -10.40   30.25   885
  18.00   -10.46   29.93   906

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