Estimates of Arctic ozone loss from temperature
Here you can see the temporal development of the area with temperatures below a typical threshold temperature that is needed for for chlorine-catalyzing polar ozone depletion. The mean value of the volume of these low temperatures is a measure of the Ozone depletion.
The upper panel shows the temporal development of the area with temperatures below this temperature threshold. The lower panel shows the corresponding volume (solid line) and the mean value between mid-December and End of March (dotted line and right arrow). For comparison, the corresponding mean values of other years are shown as coloured arrows displayed at the right edge of the plot. In 2011 this quantity was about 38⋅106 km 3 .
Basics: Proxies APSC and VPSC
APSC specifies the area at a certain height, which is below a typical temperature threshold below which the chlorine-catalyzed polar ozone depletion takes place. VPSC is the corresponding volume in a given height range (here: 14-22 km). Here the average value of this size between mid December and the end of March is considered. Since usually in cold arctic winters there is a stable polar vortex, it has been found empirically that this quantity can provide good approximations for ozone depletion . High values of VPSC mean high ozone losses.
|see e.g. Rex, M. et al., Geophys. Res. Lett., 31, doi:10.1029/2003GL018844, 2004