National Aeronautics and Space Administration

The animation shows the GEOS-5 simulation of a stratospheric intrusion that impacted several western states on April 6 and 7, 2012. The two perspectives show the 70 parts-per-billion-by-volume (ppbv) ozone isosurface, which in the early spring* is a marker of stratospheric air that usually lies very close to the tropopause (about 7-8km above the surface). Both perspectives focus on the United States and the western Pacific Ocean, with the left view looking down and generally from NW to SE, and the right view looking SW to NE to start, then later panning clockwise to look toward the N and NW. On the underlying maps, the colors indicate the proximity of the 70-ppbv isosurface to the ground, when it comes to within 3.5 km. The color legend is near the top. The progress bar shows the time. Read More.