Creating Scripts and Namelists

In order to run a new case, the case-specific scripts, namelists, and other files will need to be populated under the /scripts directory. The most straightforward way to ensure you have all necessary files to run the end-to-end system is to copy a preexisting case to a new case directory and modify as needed. In this example, we will create a new case (a typical Summer weather case; spring_wx) and model the scripts after sandy_20121027:

At a minimum, the set_env.ksh, Vtable.GFS, namelist.wps, namelist.input, and XML files under /metviewer will need to be modified to reflect the new case. For this example, the only modifications from the sandy_20121027 case will be the date and time. Below are snippets of set_env.ksh, namelist.wps, namelist.input, and metviewer/plot_WIND_Z10.xml that have been modified to run for the spring_wx case.

set_env.ksh:

This file is used to set variables for a number of different NWP steps. You will need to change the date/time variables for your case. The comments (lines that start with the # symbol) describe each section of variables.

Vtable.GFS:

On 12 June 2019, the GFS was upgraded to use the Finite­-Volume Cubed-Sphere (FV3) dynamical core, which requires the use of an updated variable table from the Vtable.GFS used in the Hurricane Sandy case. The Vtable.GFS is used in running ungrib within WPS. The updated variable table for GFS data can be obtained here.

namelist.wps:

The following WPS namelist settings (in bold) will need to be changed to the appropriate values for your case. For settings with multiple values (separated by commas), only the first value needs to be changed for a single-domain WRF run:

namelist.input:

The following WRF namelist settings (in bold) will need to be changed to the appropriate values for your case. For settings with multiple values, only the first value needs to be changed for a single-domain WRF run. For the most part the values that need to be changed are related to the forecast date and length, and are relatively self-explanatory. In addition, "num_metgrid_levels" must be changed because the more recent GFS data we are using has more vertical levels than the older data:

metviewer/plot_WIND_Z10.xml:

Change the database in the xml script to be "mv_springwx"

In addition, the other files can be modified based on the desired case specifics. For example, if you wish to change the variables being output in UPP, you will modify wrf_cntrl.parm (grib) or postcntrl.xml (grib2). If you are interested in changing variables, levels, or output types from MET, you will modify the MET configuration files under /met_config. More detailed information on the various components and their customization of WPS/WRF, UPP, and MET can be found in their respective User Guides:

• WRF User Guide
• UPP User Guide
• MET User Guide

With the scripts, namelists, and ancillary files ready for the new case, the next step is to retrieve the data for initial and boundary conditions, data assimilation, and verification.

Pulling data from Amazon S3 bucket

In this example, we will be retrieving 0.25° Global Forecast System (GFS) data from a publicly available Amazon Simple Storage Service (S3) bucket and storing it on our local filesystem, where it will be mounted for use in the Docker-space. The case is initialized at 00 UTC on 20210601 out to 24 hours in 3-hr increments.

To run the example case, first we need to set some variables and create directories that will be used for this specific example.

Then, you should set up the variables and directories for the experiment (spring_wx):

The GFS data needs to be downloaded into the appropriate directory, so we need to navigate to:

Next, run a script to pull GFS data for a specific initialization time (YYYYMMDDHH), maximum forecast length (HH), and increment of data (HH). For example:

Run NWP initialization components (WPS, real.exe)

As with the provided canned cases, the first step in the NWP workflow will be to create the initial and boundary conditions for running the WRF model. This will be done using WPS and real.exe.

These commands are the same as the canned cases, with some case-specific updates to account for pointing to the appropriate scripts directory and name of the container.

SELECT THE APPROPRIATE CONTAINER INSTRUCTIONS FOR YOUR SYSTEM BELOW: