**Hysplit Trajectory Model**
//Go to model page at: http://ready.arl.noaa.gov/hysplit-bin/trajtype.pl?runtype=archive 
  * This page is under ARL Home>Ready>Transport & Dispersion Model>HYSPLIT Trajectory Model
    * For this example I am using the **archived** not the **forecast** trajectories.

        * For the first page select the number of trajectories desire  e.g. 1. Next choose desired type of trajectories. 
          * For POLCAST data I chose to use **Normal**. Click on Next.
    
  

       

      * Under the Meteorological Data Page choose desired model data e.g. NAM (12km) and then enter Latitude or Longitude e.g. 47.9, -97 for Grand Forks. Click on continue.


      * The next page requires you to pick a day and year of the selected model data. e.g **20120709_nam12** Then click next.
      
      * The next step is to change the default model parameters and display options. For the **POLCAST** data we are interested in backward trajectories. Under Trajectory direction I chose **Backward**. For vertical motion I chose **Model Vertical Velocity**.  Under Start Time UTC I chose: year: 12 month: 07 day: 09 hour (For hour I chose the closest hour to the start time of the seeding fights): 18. Under total run time I chose 24 hours (how far back to go). I put 24 as the maximum number of trajectories. The height level was calculated through the CPLOT software (statistics tool) e.g. **2000 meters AGL.** . Then under GIS output choose Google Earth (Kmz) file. Leave the default of the rest of the parameters.  Then click on **request trajectory**.
   
      * It will take a few minutes for the images to load.  Once it is complete there should be** a GIF, and 2 Google Earth KMZ files** of the trajectories.  

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