Graphics: NCL

With the use of NCL Libraries (, WRF ARW data can easily be displayed.

The information on these pages has been put together to help users generate NCL scripts to display their WRF ARW model data.

Some example scripts are available, but in order to fully utilize the functionality of the NCL Libraries, users should adapt these for their own needs, or write their own scripts.

NCL can process WRF ARW static, input and output files, as well as WRFDA and WRF-Chem output data. Both single and double precision data can be processed.


What is NEW?

In July 2007, the WRF-NCL processing scripts have been incorporated into the NCL Libraries, thus only the NCL Libraries are now needed.

Major WRF ARW related upgrades have recently been added to the NCL libraries. In order to use many of the functions, NCL version 5.1.0 or higher is required.

Special functions are provided to simplify the plotting of WRF ARW data.
These functions are located in "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl".

Special NCL built-in functions have been added to the NCL libraries to help users calculate basic diagnostics for WRF ARW data.

All the FORTRAN subroutines used for diagnostics and interpolation (previously located in wrf_user_fortran_util_0.f) have been re-coded into NCL in-line functions. This means users no longer need to compile these routines.


What is NCL

The NCAR Command Language (NCL) is a free interpreted language designed specifically for scientific data processing and visualization. NCL has robust file input and output. It can read-in netCDF, HDF4, HDF4-EOS, GRIB, binary and ASCII data. The graphics are world class and highly customizable.

It runs on many different operating systems including Solaris, AIX, IRIX, Linux, MacOSX, Dec Alpha, and Cygwin/X running on Windows. The NCL binaries are freely available at:

To read more about NCL, please visit:


Necessary software

NCL libraries (we recommend version 6.0 or higher).