Geogrid

Preliminary

Before we start executing geogrid.exe, ungrib.exe, and metgrid.exe, we need to create a folder named WRF_Resources to put all the required input data for WPS. We will download all the required data into the /scratch folder. If you have downloaded them, proceed to edit the &geogrid section in the namelist.wps.

cd /shared/scratch
mkdir WRF_Resources
cd WRF_Resources

Download the geogrid data

You can download the mandatory high-resolution data from the official website of UCAR: Download data for the input of geogrid.exe. There are two types of datasets available, each made up of the highest and lowest resolution of each mandatory field. You may read the details on the official website to decide on the data that suits your needs. In this case, we will be using the highest resolution of each mandatory field.

wget https://www2.mmm.ucar.edu/wrf/src/wps_files/geog_high_res_mandatory.tar.gz
tar -xf geog_high_res_mandatory.tar.gz

Edit the geog_data_path in the namelist.wps

Point the directory of high-resolution data to WRF_Resources in the nameslist.wps. To do that, you must first obtain the path to WPS_GEOG.

cd WPS_GEOG
pwd

Copy the path and go to the directory /shared/scratch/WPS/WRF_Resources/WPS_GEOG/ where your WPS was compiled and edit the namelist.wps.

cd /shared/scratch/WPS/
nano namelist.wps

Under the &geogrid section, edit the geog_data_path and save it.

Edit the &geogrid section in namelist.wps

Before executing geogrid.exe, edit the information in the namelist according to your case. Read the description for each listed variable in the namelist, as well as best practice here. We will use the information provided in the Resources tab in this tutorial.

Export the LD_LIBRARY_PATH and run the geogrid.exe. Ensure you had loaded the intel-oneapi-compilers and intel-oneapi-mpi using spack to avoid the issue of missing libiomp5.so.

export LD_LIBRARY_PATH=$(spack location -i netcdf-fortran%intel)/lib/
spack load intel-oneapi-compilers
spack load intel-oneapi-mpi
./geogrid.exe

If geogrid.exe runs successfully, the following output will be printed: Successful completion of geogrid.

The files that are created by the run will be in the folder. They are shown in the image below:

ls

View and adjust namelist.wps to fully cover the domain interested before running the simulations

First, open a nice DCV session. Go to the WPS directory, which in this case is /shared/scratch/WPS/. Now we are going to load the ncl package using spack.

spack load ncl

Now, type the following command to view the plot. Pay attention to using the new script as it is written for NCL version 6.2 or later.

ncl util/plotgrids_new.ncl

You have created the plot using DCV!

Now repeat the previous process of editing the namelist to adjust the simulation so that it covers the interested domain. Be noted that this is for temporary viewing only. Proceed to the next section if you want to save the file locally.

Create plots in pdf format

To export the image to PDF in the cluster, we will edit the ncl script in the util folder.

cd /shared/scratch/WPS/util
vim plotgrids_new.ncl

Look for the part where it starts with We generate plots, but what kind do we prefer?. Change the type from x11 to pdf and save. After x11 describes the title, you can name your file. In this case, we will name it DOMAIN.

Run the ncl script in the WPS folder again using the DCV session. If successful, you will see a file named DOMAIN.pdf.

Now, we are going to export the file to the local computer. Copy the DOMAIN.pdf to the home directory.

cp DOMAIN.pdf /home/ec2-user

Export the file from the DCV session by clicking the file storage icon. Choose the file interested, and click Actions to download the file.