The FTP Satellite Data tab from the Advanced menu provides access to selected NASA and NOAA satellite archives. The Particle Editor / Viewer also displays the corresponding satellite image. An example of how the Advanced menu features can be used to view the TOMS aerosol index satellite image, and then adjust the model plume position before continuing on with the model calculation is explained in the following discussion. This is a pre-configured example only for demonstration purposes.
1) From the Concentration Setup menu, retrieve the standard example configuration sample_conc. Then modify the run time from 48 hours to 16 hours. The data file starts at 16 Oct 1995 on 0000 UTC. The first part of the simulation will end at 1600 UTC. This is close to local solar noon and approximately corresponds with the time of the TOMS image at the longitude of the US East Coast.
2) Go to the Configuration Setup of the Advanced menu and press the bottom Reset button to bring all values back to their default. Then change the value of 1st Particle Dump from 0 to 16 hours. This configures the model to write the particle position file PARDUMP after 16 hours runtime. Save to exit the menu.
3) Now press Run Standard Model from the Concentration menu.
4) At the end of the simulation, go back to the Advanced menu and from View MESSAGES, review the MESSAGE file. Note that at the bottom of the listing the note that the PARDUMP file was created for 498 particles at 95 10 16 16, then Exit.
5) TOMS data for the 16th of October 1995 are not available, however a dummy file (for another date and renamed to reflect the simulation time) has been placed in the ./working directory. Therefore no FTP is required. For other simulation times, use the NASA TOMS tab of the FTP Satellite data menu to ftp the daily file from the proper date. More information about TOMS data is available.
6) Open the Particle Editor from the Edit/View tab to display the particle positions given in the PARDUMP file found in the ./working directory. In addition, the program can overlay the TOMS image for the sample data. Various images can be displayed and the particle positions manipulated as shown in the illustration below. More detailed instructions about this process are available.
7) Once the PARDUMP file has been adjusted to improve the comparison with the satellite data, go to the Configuration Setup menu and write particle initialization time from 16 hours to 24 hours and then Save. The model will be run another 24 hours and a new PARDUMP file will be written. Satellite passes are about every 24 hours over the same longitude.
8) From the Concentration Setup menu change the run time from 16 to 24 hours, and explicitly set the model starting time from all zeros to "95 10 16 16". Emissions need to be turned off, unless the source is continuous. In this example turn off emissions from the Pollutant selection of the Pollutant, Deposition, Grids Setup menu bar and set the emission duration from one hour to 0.0 hours. Then run the model.
9) At the completion of the simulation, review the MESSAGE to confirm that the model initialized with 498 particles (total mass still 1.0) and that a new PARDUMP file was created for the 17th. The point of this exercise is to demonstrate how the model fields can be adjusted to correspond with measured data prior to running a simulation with forecast data, times at which no measurement data are available.