The Ozone Monitoring Instrument (OMI) aboard NASA's Aura spacecraft is able to "see" the "hole" that develops in the ozone layer above Antarctica every winter. What is known as a "hole" in the ozone layer (the layer of concentrated ozone that resides in the stratosphere) is actually a thinning or depletion of ozone concentrations in the stratosphere. Due to a complex series of physical and chemical reactions in the atmosphere, this thinning happens every winter in the southern hemisphere. As summer approaches in Antarctica, the ozone hole disappears, and normal ozone levels return. As Aura orbits the Earth, the data OMI takes enables scientists to study this chemical cycle. You can view a movie of the 2007 ozone hole from the Ozone Watch website:
http://ozonewatch.gsfc.nasa.gov/ozone_maps/movies/OZONE_D2007-07-01%25P1D_G%5e720X486.LSH.mpg
