Table of Contents

5.1   Introduction
5.2   Running the WRF Static Initialization GUI

5.1     Introduction

Author's note: Some of the verbiage contained within this tutorial was liberally adapted or pulled verbatim from "USERS GUIDE TO THE GRAPHICAL USER INTERFACE TO PREPARE THE STANDARD INITIALIZATION FOR WRF VERSION 2.1" by P. McCaslin, J. Smart, and B. Shaw. The full document is available in the docs/wrfsi directory of the WRF EMS package if you are interested.

The WRF package includes a very useful graphical user interface (GUI) tool that was developed by Forecast Systems Lab (FSL) for use with the ARW core and modified by the STRC for use with the NMM core.

In order to run the GUI tool you will need PerlTk libraries (Version 804.027) installed on your system. The Tk extension to Perl does not come with the standard Perl distribution; however, during the process of installation, the script will attempt to build the necessary PerlTk libraries using your gcc compiler. If this step fails, the installation script will then install STRC-compiled libraries, which should work. If you encounter problems with running the GUI then contact me.

 

5.2      Running the WRF Static Initialization GUI

If the installation of the system goes smoothly you should be able to run the GUI,

% sigui (Static Initialization GUI)

at which time the application's GUI window should appear (below). Always present in the GUI window is the standard menu bar at the top of the window. The user can exit the application or query the help pages and version information by selecting options found under the File and Help buttons of the menu bar, respectively. At the bottom of the GUI window, a User Hints & Information text area sometimes suggests steps to be taken, and at other times summarizes the success status of the step that has recently been completed.

Editor's comment: The best way to learn how to use the GUI is by playing with the tool while an expert looks over your shoulder. Unfortunately, you will have to be more proactive in educating yourself on the fundamentals of the Static Initialization (SI) GUI. I am available for phone training if necessary so don't hesitate to call.

 

There are a few important things to keep in mind when running WRF SI GUI:

a. The Map projection you select will determine which WRF core (NMM or ARW) you will run. Select the rotated latitude-longitude projection (rot lat-lon) for the NMM core and the "Lambert Conformal", "Polar Stereographic", or "Mercator" projections for the ARW core.

b. If you are planning to display your ARW forecasts in AWIPS then it is recommended that you use the Lambert Conformal projection instead of the polar stereographic or Mercator. The NMM forecast files will be remapped from the Rotated Lat-Lon Arakawa-E grid to a Lambert Conformal projection during the post processing stage.

c. The internal definition for the distance between grid points for the NMM core is similar to that of the WS Eta (degrees); however, the GUI has been modified to accept the more traditional input of kilometers.

d. You must run a successful localization in order to proceed with your run.

After starting the GUI, click on the "Domain Selection" button, which will bring up the Domain Panel window (below).

 

This step begins the process of defining a computational domain. At this point users must choose from four options on the pull-down menu under the instruction "Choose what you want to do". These options allow the user to create, load, copy, or delete a domain. After a domain is created, only then can it be edited, copied, or deleted.

Within the Domain panel are four entry box fields for entering information; 1) the domain name; 2) the path to your domain directory; 3) a description of the simulation, and 4) a user description.

To edit an existing domain, choose the "Load" option from the pull-down menu shown on the Domain panel under the instruction "Choose what you want to do". Then, choose a domain of interest from the list of available domains. This loads an existing domain into the GUI. Everything about an existing domain can be modified except for its name.

For the purpose of creating a new domain it is recommended that you follow the steps depicted in the image above. After clicking on the "Next" button, you will see the "Horizontal Grid" selection utility.

 

The Horizontal Grid panel interface allows the user to define a model domain by drawing a bounding box on a map (left side) and editing map projection variables (right side). You will use this window to draw a box around the general area that will define your computational domain and choose a map projection. You will be able to fine-tune the domain in the next window so there is no need to be exact here.

The initial global map image above shows a Cylindrical Equidistant projection of the world centered at Latitude 41.58 and Longitude -81.90. The entire global map is not displayed all at once, but the panel has sliding scroll bars on the bottom and right sides to reposition the image within the panel. The map image can be increased or decreased in size by pressing the appropriate zoom-in or -out buttons located above the upper left corner of the map image. The map projection's interface (right side) is used to select the background map, projection type, and center point values.

Initially, only the global map is active at this step and all other interface buttons are disabled. As the user presses mouse button 1 (left) on the global map and drags the mouse to a new location, a white domain-bounding box will be drawn that specifies a domain. Qualitative status information will be displayed in the User Hints & Information panel, specifically the lower left (LL) and upper right ( UR ) corner latitudes and longitudes and the total number of X, Y grid points in the selected domain. The total number of X grid points for a new domain is 100 for ARW and 51 for NMM. Y is calculated as a function of X and the surface area covered by the domain-bounding box. These area calculations also determine an initial value for grid spacing.

The WRF-ARW SI satisfies global domain localizations for three commonly used map projections; Lambert Conformal (both tangent and secant), Mercator, and Polar Stereographic. The WRF-NMM SI uses a rotated latitude longitude projection. Basic understanding of map projections is valuable but not mandatory because the GUI has built-in criteria to suggest to the ARW user a projection type based on the domain's center point latitude value.

Note: As stated previously, your choice for map projection will determine whether you are running the NMM or ARW core of the WRF model. If you want to run the NMM core, select "Rot Lat-Lon (NMM)" in the Map Projection window. If you want to run the ARW core then you can choose "Polar Stereographic", "Lambert Conformal", or "Mercator"; however, it is strongly recommended that you choose "Lambert Conformal", especially if you want to ingest your forecast files into AWIPS.

When the user presses "Update Map", both the map and map-editing interface of the Horizontal Grid editor are updated. The map is now displayed in projection space based on user-selected information.

 

At this point you will likely fine-tune your computational domain for your grid dimensions and spacing. Click on the "Grid & Projection Values" button, which will allow you to edit these values. Pressing the Grid & Projection Values button (Fig. 7) selects the mode to allow the user to adjust the domain bounding box grid values, but it will prevent the user from editing the box graphically.

After selecting the "Grid and Projection Values" button you will be allowed to edit the domain center point, NX and NY values, and the grid spacing. The GUI will display the domain on the projection that you selected.

 

There are several background maps available for use with the WRF SI GUI. Most of the files cover the US and originate with NWS AWIPS D2D workstation maps. If desired, the user can choose to add additional map files to the database. Once a map file is created, it needs to be located in the wrf/gui/map directory in order for the GUI to automatically add this new choice to the list of map background files found under the pull-down list. The software for creating map background files originates from the NWS AWIPS use of ARCINFO shapefiles. Information on creating your own custom map background for the WRF SI GUI can be found at

http://www.wrf-model.org/gui/map and http://www.wrf-model.org/gui/map/readme_file.txt.

At the bottom of the map projection interface are four action buttons; Clear, Start Over, Reset Values, and Update Map. The Update Map button will draw a map from a domain-bounding box and grid values. The Start Over button will undo all commands that updated the originally drawn domain-bounding box into a domain map. The Clear button erases the domain-bounding box, returning to the global map that resets all widget values. The user can fine-tune the domain bounding box by pressing the Update Map button again to commit to these changes or press Reset Values to cancel the pending changes.

You may enter values into the box directly or use the up and down buttons to modify your domain. Each time you make a change the white bounding box will change slightly. After you are satisfied with your computational domain click on the "Update Map" button.

 

Once you are happy with your domain continue to the vertical coordinate specification by selecting "Next". There will be a short delay in advancing to the next window as information files and a gif image depicting your domain will be created and placed in the wrf/runs/<domain>/static directory called domain.gif.

 

The Vertical Grid panel allows the user to view sigma levels (left side) and edit these levels (right side). The layers represented in the display on the left hand side of the window appear only in the GUI, as additional information for the user to evaluate sigma level minimum and maximum thickness values.

There are several options for editing the sigma levels. One option allows the user to enter the number of levels, choosing one of three sigma level schemes to automatically generate the selected number of levels. The options for schemes are to calculate linear levels in sigma, to calculate square root levels in sigma, or to calculate the top one-third of the requested levels in linear and the lower two-thirds of the requested levels in square root in sigma. A second option is to load an existing file of sigma levels.

A third option allows the user to add or remove sigma levels via a text-editing window. Pressing View Levels (found below the text editing window) processes user inputs and displays the sigma values. A quality control filter eliminates values greater than 1.0 and less than 0.0, as well as duplicated and non-numerical values. Status information sent to the User Hints & Information panel contains the minimum and maximum sigma height distance values. Vertical sigma levels can be displayed in log pressure or not with the press of the "Log Pressure" button.

If you want to change the number of vertical levels the easiest method is to select "Calc Linear in Sigma" from the drop-down then edit the number of levels to meet your needs. You should see the levels changing in the box below.

Note: The value for the "Pressure at top of Model (mb)" must be below the top level of data in your initialization and boundary condition data sets. Otherwise the model will fail during initialization. The default value (50mb) is fine for most data sets.

 

Once you are Happy with your levels move on to the vertical coordinate specification by selecting "Next".

 

The only parameters in this section that can be modified via this panel are SILAVWT_PARM_WRF and TOPTWVL_PARM_WRF that defined the representation of topography in your run. These parameters are only valid for the ARW core. Some documentation on these parameters is available if you are interested.

Move past the "Localization Parms" window by selecting "Next" again.

You will now find yourself in the "Localize Domain" window. The only step is t0 create a localization and make sure it was successful. During the localization, terrain, land use, soil type, etc. information for your domain will be extracted from the files in the wrf/data/geog directory and placed in your wrf/runs/<domain>/static directory. If the localization fails, there will be a warning or error message in the window with more details provided by the wrf/runs/<domain>/log/localization.log file.

 

 

At this point you are done; however, you can continue to the next step by displaying some of the static localization files that were created for your domain by selecting "Next" and going on to "Domain Graphics", but it is not necessary. To quit, simply select "File" and "exit" from the drop-down window at the upper right of the GUI. Answer yes to both questions and you are done.

Now is the time for all good people to model.