Welcome. We assume users like yourself would like to track a few particles through ocean modelled flow fields on the Northeast Continental Shelf and you only want to track them for a few days. If you are interested in tracking more than a few particles for a longer time you might be better off downloading the package to your machine and running it there. Whatever works best for you. We hope to be always improving this web utility and posted package in the future so we encourage you to comment and request changes/improvements. Contact

How to run this web version in two basic steps:
  1. Select the “Start Option” mode which determines how you specify initial points
    1. Click Map” default option allows the user to click on the map     
      1. multiple clicks are allowed but, unless you are very patient, don’t click too many
      2. Track Steps:
        1. Click on the map.
        2. Choose Model grid.
        3. Set Depth(m).
        4. Choose Track direction.
        5. Set Start time.
        6. Set Number of days to track
        7. Click button "Submit".
        • The yellow line on the map is the boundary of the model grid.
        • It will take 1-3 minutes(depends on quantity of Step1 and Step6) to get result.
      3. if you plan to use something other than the “massbay” model grid, you can zoom out to include the entire Gulf of Maine and Southern New England
    2. Specify lat/lon” provides a text box for the user to enter latitude and longitude in decimal degrees in the text box on the right panel
    3. Use drifter fix” option requires the user to know two things and to enter them in the text box on the right panel     
      1. “Drifter ID” is typically a 9-digit drifter deployment code (pe“154420701”)
      2. “Date type” is the name of the raw drifter data (pe “drift_su_2014_1.dat”)
      3. This option currently starts your modelled particle track at the last observation of the drifter so it is, in effect, forecasting where the drifter will go in the future.
  2. Select the other options on the right hand panel which all include     
    1. Model grid     
      1. your selection here will govern what model output time range is available
      2. massbay and gom3 grids typically allow +/- 3 days from present and 30yr grid allows 1978-2013
    2. Forward or backward tracking
    3. Time to start     
      1. using format as shown in the example 2015-3-25 11:45 where hours are in UTC
      2. depending on the Model Grid you choose your desired time may or may not be available
    4. Number of days to track     
      1. this can be in fractional days is needed
How to download and run the track program locally

The full package for super users is on the “Particles-in-the-Coastal-Ocean” GitHub page under the Track_python repository. There is a README file there and some additional documentation under a the “planning lessons” pull down menu on the “” website.


While parts of this particle tracking routine were originally written by Jim Manning and Vitalii Sheremet, it has been further developed over several years by various programmers who have come and gone (Jian Cui, Conner Warren, Nkosi Muse). It is currently maintained and greatly improved by Bingwei Ling. All of the above conducted this work at NOAA’s Northeast Fisheries Science Center while learning how to use Python. We also acknowledge the modellers, Changsheng Chen especially, who provide their output freely via OPeNDAP.