nixfiles:
Bay Area winds

This applet uses a particle system to visualize wind patterns in the San Francisco Bay Area, using observed wind data and a computed vector field based on these data.

The applet here is based on data from Sun Jul 25 17:35:02 PDT 1999, but thanks to the good folks at USGS you can find a current animation at http://sfports.wr.usgs.gov/wind/streaklines.shtml.

The source code for the applet is available under the terms of the GPL.

Many thanks to Chad English at USGS for making the raw data available, and explaining how to interpret it, and putting the applet up on the USGS site so that people can see the latest wind patterns.

The applet may take a while to start up - the data points are stored in a text file that takes up 130K. This could be sped up by representing each data value in 2 bytes (instead of about 5) and by using fewer data points.

You can stop/start the animation with a mouse click.