For the impatient:

1. Get the distribution. Here is the most recent version 1.3 from December 24, 2007. The new version has several new features compared to the last release 1.2 from December 24, 2006, see Newsletter 8.
   
   Older versions are also still available (if asked for username and password, please try libRadtran for both).
   
   If you download the package we ask you to send us a short eMail to let us know that you use the model. We have created a mailing list of libRadtran users in order to notify them of additions, changes, and bug fixes on an irregular basis.
   
   
2. Unpack the distribution:
        gzip -d libradtran-x.yy.tar.gz
        tar -xvf libradtran-x.yy.tar
   where x.yy is the version number.
   
   
3. Compile the distribution:
        cd libRadtran-x.yy
        ./configure
        make
   
   
4. Test the program:
        make check (make sure to use GNU make)
   
   
5. Get additional modules if required:
   • Mie water and ice cloud properties for the k-distributions provided with libRadtran and for the wc/icproperties_interpolate options, either in ASCII or preferably in netcdf format.
   • A detailed version of the Baum et al. ice particle optical properties (80 MByte!). The distribution contains only a reduced data set where the scattering phase function is less accurate, in particular in the forward peak and all sharp features like the HALO.
   • An example for a line-by-line absorption cross section profile for the oxygen A-Band around 760 nm; UVSPEC.O2A.afglms.cdf can be used as molecular_tau_file, see the libRadtran documentation of this option.

The following software is required to successfully compile, link and run all of the libRadtran tools:

• GNU make. The compilation might work with other make programs, but usually it doesn't.
• The GNU C compiler (gcc). Other compilers might also work.
• A Fortran compiler that is compatible with the C compiler. If a C compatible Fortran compiler is not available, f2c will do the job.
• Flex - The Fast Lexical Analyzer. Is usually available for all flavous of Linux, under Mac, and for cygwin, but not necessarily installed by default. You may have to select installation of flex manually.
• The Perl programming language, version 5.004 or later, is required to run the automatical test.

Users of Windows 95/98/NT systems are asked to consult the installation of libRadtran under Windows instructions. Compilation under Windows is possible with only little more effort than on a Unix system.