Tuesday, April 20, 2010

Fun with Finite Elements

We met a family from London at our NYC hotel.  Their 4 day trip to NYC was turning into a two week nightmare.  Their return flight was pushed back from April 17 to April 27 due to volcanic ash!  I don't want to get into an argument about the sustainability of airplane travel (and my own enviroguilt about flying LAX to JFK RT for Spring Break).

Anyway, you can make your own simple trajectory calculation with NOAA's HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model. Model access via NOAA ARL READY http://ready.arl.noaa.gov/HYSPLIT_traj.php.

BTW, I initiated forward trajectories at three heights every 3 hours for 72 hours starting near the Eyjafjallajokull Volcano, Iceland.  Although READY allows you to run volcanic ash and dispersion models, I used a simple advection model to generate this plot.

The trick is to select the right meteorological dataset for your winds.  The web interface assumes that you know that
NAM is North American Mesoscale,
RUC is Rapid Update Cycle and
GFS is Global Forecast System.

NAM and RUC cover only North America.  If you want a map that includes other areas, there is only one choice, GFS.  Have fun and don't swamp the server.

I wrote a follow-up with step by step instructions for how to use the NOAA interface in Do you know where that's been?

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