Graphical User Interface (GUI) Operation

The HYSPLIT package for computing trajectories and plume dispersion consists of a series of command line based executable programs that are integrated through a number of different scripts, all invoked through a Graphical User Interface (GUI). An overview of the GUI follows:

1. Once the installation is complete, that is the HYSPLIT code and all the auxiliary software are installed, then click the desktop icon Run Hysplit and a startup window will be shown. Select the menu button to proceed.


2. The main menu consists of four main tabs: meteorology, trajectory, concentration, and advanced. There are multiple sub-tabs under each main tab which are all shown in the open position in this document for illustration. Individual sub-menus will be discussed as needed.


3. The meteorology tab provides for different ways to access meteorological data files and load them into the local computer to perform trajectory or dispersion calculations. For the purposes of this tutorial, all required meteorological data files are provided with the HYSPLIT installation or in the directories of the tutorial CD-ROM.


4. The trajectory tab opens access to sub-menus to setup the trajectory simulation, run the calculation, and then display the results. A trajectory is just the integration of the position vector through a wind field that varies in space and time. The point is assumed to be passively transported by the wind.


5. The concentration tab has similar sub-menus to the trajectory calculation. The primary difference between the two is that the trajectory calculation only follows one point transported by the mean wind, while the concentration calculation may follow thousands of trajectories at the same time, the motion of each being composed of a mean (trajectory) and turbulent (dispersive) component. In addition, each "particle" trajectory associated with the concentration calculation has some mass assigned to it which means that the trajectory density can be used to compute an air concentration.


6. The advanced tab is used to set additional model parameters that can be used to provide further control or customization to either the trajectory or concentration calculation. The information is written to a namelist file, always called SETUP.CFG. A namelist file contains the value of various program variables defined by their internal code name. Some other miscellaneous features can also be found under this tab.


7. The following installed sub-directories will be found under \hysplit4\ ...
   
   • cluster - The default location for clustering trajectories.
   
   
   • data2arl - The source code for programs not already available through the GUI that can be used to convert meteorological data files from models such as MM5 and WRF-ARW to the HYSPLIT compatible format.
   
   
   • datem - Contains sample HYSPLIT input files for various experiments available from the DATEM repository and experimental data for CAPTEX
   
   
   • document - Contains the technical manual, user's guide (pdf), and various README files.
   
   
   • exec - Contains all the HYSPLIT executables, which may be for either 32-bit or 64-bit operating systems depending upon which file was downloaded. Note that the directory contains additional programs that are not available through the GUI but can be run through the command line prompt.
   
   
   • graphics - This directory contains the default ASCII map background file (arlmap) that is used by all the HYSPLIT graphical display programs. Other more detailed ASCII and binary shapefile map background files are also available in this directory.
   
   
   • guicode - This directory contains all the TCL scripts required for the GUI. The root script is hysplit4.tcl which is also the target of the desktop icon.
   
   
   • html - This directory contains all the context sensitive help files that are individually invoked from the GUI menus from the Help button. The index.htm and all other help pages can be opened in any browser.
   
   
   • testing - This directory contains the xrun.bat batch file which can be used to test various model simulations. The script can be used as a template to develop other customized scripts.
   
   
   • working - The working directory is the root directory for running HYSPLIT. By default the model looks for input files here and writes all the output files to this directory unless other paths are set in the simulation setup.

8. The basic model operation involves three steps. First Setup Run configures the simulation details and saves the information to a file called default_traj or default_conc. Second, when Model Run is invoked, the default_???? file is copied to a file named CONTROL which is then read by the model executable. Third, the Display menu will call a program to read the model output file and will create a Postscript graphics file. These are all written to the working directory.

In subsequent tutorial pages these menus will be explored in considerably more detail.