Details and instructions on the trajectory tool page

Page will plot trajectories that are calculated using various reanalysis datasets. A 3D calculation is used, using analyzed pressure level winds from 10000mb to 100mb.
Datasets | Dates | Starting/Ending location | Page Creation | Feedback

If you have problems, please email with ALL the options you chose. You will get a plot as well as the data used to create the final plot (in netCDF), a post script image and information on the dataset.

  • Datasets
    Various global reanalyses are provided. Note that different reanalyses dataset have different levels. We use all the levels up to 100mb.
  • Enter Dates
  • Enter a starting and ending date. If the 2nd date is greater than the first, you will get a backward trajectory calculation. All dates in the trajectory date range need to be in your selected dataset and they need to be proper dates. Hours are 0,6,12, and 18 (Z). Only enter numbers.
  • Starting point
    These values with be used as a starting point (or an ending point for backward trajectories). it is possible to enter a location that is below the surface. The reanalyses datasets used on this page are interpolated below the ground.
    Latitude range is -90 to 90.
    you can enter longitudes as degrees east (0 to 360) or degrees west which is entered as negative longitudes to -180 (e.g. -100 is 100W or 260E).
    Pressure level of initial point, in millibars
  • How this page was created
    The main interface for this page is an HTML form. The data that are input into this form are processed by a Perl script. The script reads the inputs, tests for bad inputs, runs the trajectory code and then is plotted using NCL. NetCDF, KML and postscript are also produced. The netCDF file, image and other files are kept in a directory in which the files are periodically deleted.
  • Feedback
    Please let me know if find the page useful. Likewise, let me know if you think any instructions are unclear, if you think there are bugs or if you have any suggestions for improvements of any type. I would particularly like to know if you use these pages for teaching purposes and if so, how. I can be reached by email at or by phone at (303) 497-6263.