## Advanced / Help

This section provides some guidance in configuring the model to perform certain specialized calculations. These include deciding between particle or puff releases, dealing with continuous emissions, area source emissions, multiple pollutants, pollutant transformations, atmospheric chemistry, deposition and decay, compilation limits, scripting for automation applications, backward dispersion for source attribution, configuring the time or spatial variation of the emission rate using an input file, and how to compute deposited pollutant transport on ocean water surfaces. The Advanced menu is composed of four sections.

1. The Configuration Setup menu permits the creation and modification of the SETUP.CFG namelist file for either Trajectory or Air Concentration calculations. The namelist file is a variable length file that is used to set additional parameters that can be used to modify the nature of the simulation. The namelist file is not required because all the namelist variables take on default values when the SETUP.CFG file is not found. The same namelist file can be used for either trajectory or air concentration simulations but only certain variables are applicable to each simulation. Supplemental plot labeling options are available, a menu to configure a dynamic sampler that can move in space and time for use with the concentration simulation, and a menu to configure the default directory structure and location of executable programs used by the GUI. More complex point source emissions scenarios can be defined by creating the EMITIMES emissions file.

2. The Satellite Data menu opens two special menus that deal with downloading and displaying TOMS satellite data. The FTP NASA TOMS satellite data menu opens up an anonymous FTP window to access the current satellite archives for the TOMS aerosol index (AI). These data can then be displayed through the TOMS Viewer. In addition to AI, the viewing program will also display the pollutant particle positions. The particle position file, called PARDUMP by default, is a snapshot of all the pollutant particles at a given time. Its creation is controlled through the configuration menu.

3. The View MESSAGES menu is used to display the diagnostic message file. For all trajectory or concentration simulations, diagnostic information is written to standard output until the initialization process has completed. At that point the MESSAGE file is opened and subsequent diagnostic and certain error messages are written to this file. If the model does not complete properly, some additional diagnostic information may be obtained from this file.

4. The Scan for Updates menu can be used to make small updates to a limited number of executables and scripts for the same HYSPLIT release version. Updates to executables and scripts may be posted to the ARL web server. This menu compares the dates of those updates with the installed versions. If newer programs are available, you will be prompted to replace each with the update. Older programs are copied to the updates directory and the update can be reversed if desired. The update process only changes programs in the ./exec directory and scripts in the ./guicode directory. Once a significant number of updates have accumulated, the entire release version will be updated and a new installation must be manually downloaded from the ARL server. Only updates to the same version number are permitted.

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