• Fortran 90/95 and C compiler
• MPI or OpenMP libraries
• netCDF4 library linked with HDF5 and zip libraries and extended by the Fortran netCDF package (The netCDF4 package comes with the programs ncdump and nccopy)
• UNIX utilities: ksh, uname, sed, awk, wget, etc.
• GNU make
• For post-processing: Climate Data Operators (CDO) and netCDF Operators (NCO)

 The climate mode of COSMO (CCLM) uses netCDF I/O. If you want to use GRIB1 or GRIB-API for the model I/O instead, you need to get the source code of these libraries from one of the partners of the COSMO consortium. You also need to adjust compilation and namelists of INT2LM/CCLM in this case.