NU-WRF stands for NASA Unified WRF. This is an augmented WRF code with additional software developed at NASA. This WRF version has been primarily chosen in order to run CABLE coupled to WRF through the LIS software. There are additional softwares distributed along WRF in NU-WRF:
These are still distributed on NCI machine but they have not been ported or tested by the CMS team.
Following are the links to the official relevant manuals for each software:
LIS is under licence. To restrict access to the NU-WRF code, it was set as a private repository on | BitBucket. To gain access to the repository, send an email to [| climate_help] to request the connection including the email address you want to link to BitBucket. You should then receive an invitation to join the NU-WRF repository.
Clone the repository.
Once you have access to the BitBucket repository, you need to clone the repository onto the NCI machine. There are two ways to clone from BitBucket, you can either use a HTTPS link or a SSH link. Both work with NCI machine. With HTTPS, you will need to provide your BitBucket password at each connection. For SSH, you will need to first create a SSH key but then you can setup the system to retrieve the key automatically without entering it (see | BitBucket help). Cloning the repository should create a local repository in your file system called nu-wrf.
Since NU-WRF has been ported to NCI, you should be able to compile the WRF/WPS components of NU-WRF straight away. The code comes with the script nu-wrf/run_build. Please review the script to choose the appropriate compilation options (you can compile LIS alone or WRF alone or WRF coupled to LIS and/or WPS) and PBS options. For a successful compilation, the output script should contain a line reading:
Completed build of <component_name> component of NU-WRF!
where <component_name> is replaced by the name of the compiled component. Note that if you ask for compiling two components at once (e.g. WRF and WPS), you will need to search for the "Completed" line for both components.
Running WRF with LIS
Normally to run a real simulation with WRF, the user has to create the boundary condition files with WPS then run WRF. Using LIS modifies the workflow in several ways (see graph):
- Interpolate the LIS input data to the grid resolution used for your WRF simulation.
- Run LIS offline (i.e. not coupled to WRF) on the exact same grid that will be used for the WRF simulation. You are required to save a certain number of fields that will be used to create the input conditions for WRF. This phase is called the spin-up.
- real.exe has been modified and now queries input from both WPS output and a LIS output file.
- wrf.exe will expect a LIS restart file and a LIS configuration file.
Scripts have been developed by the CMS team to facilitate the management of simulations with NU-WRF on NCI machines, including to run the spin-up and ensure the concordance of information between WRF and LIS configuration files. It is assumed that a user has access to NCI servers. However, since the workflow is based on template files, these are easily customisable to use on any machine. These also provide the possibility to store inputs and outputs on a different machine and to automatically move the files across machines for each run. The scripts are in a public Git repository on Bitbucket: | NU-WRF scripts.
See the NU-WRF workflow page for instructions about these scripts. These instructions will run you through testcases for CABLE through LIS only and CABLE-LIS-WRF.