2.3 Test Trajectory Calculation


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From the top bar of the main menu select the Trajectory / Quick Start / Run Example menu tabs. The Run Example tab initiates a windows only program that displays a source selection menu. On non-windows system, the calculation just proceeds without any prompts. A left-click resets the source location, while a right-click closes the selection window. Pressing and holding the left mouse button while dragging the cursor rescales the map over that region. Although any location can be selected, only locations within the domain of the meteorological data file will initiate a calculation. For the purposes of this test, just right-click to accept the default location, which then results in window termination message. Select Yes and then ...

  1. A file named CONTROL is created in the working directory with the starting time, location, meteorological data file name, and trajectory endpoints output file name.

  2. The trajectory model is then run which creates an ASCII output file called tdump with the endpoint locations.

  3. A trajectory plotting program is run which reads the tdump endpoints file and creates the Postscript graphics file called trajplot.ps.

  4. The Postscript graphic is displayed using Ghostview.

  5. These files can all be found in the HYSPLIT working directory and in addition to the above named files the directory also contains diagnostic files such as MESSAGE, TRAJ.CFG, and if needed WARNING.

  6. The Quick Start menu is the easiest way to enter the latititude-longitude of a new location from a map if no other detailed source information is available. The model simulation will use all the other settings from the last simulation.

The display of the trajectory graphic means that all the HYSPLIT components have been correctly installed. In the unlikely event that the installation failed and the graphic was not displayed suggests that there may be issues requiring system administrator support. Consider the following:

  • You have permission to install software.
  • You have write permission to the directories in which the software was installed.
  • You are not installing on top of a previous version of HYSPLIT.

The display of the three-trajectory graphic means that all the HYSPLIT components have been correctly installed. In subsequent simulations through the GUI, the Quick Start menu would normally not be used because it automatically combines three individual steps: configuring the model simulation, running the simulation, and converting the output to a graphical format. These components will be explored in more detail individually. Many of the features available through the GUI apply to trajectory as well as air concentration calculations. After testing the air concentration simulation in the next section, the trajectory calculations will be explored in more detail.