Annual ozone holes compared by area and duration

This graph compares this year's new-born ozone hole - represented by dots - with those of previous years, in terms of area, in millions of square kilometres on the vertical axis and time duration, on the horizontal axis. The hole is defined as a thickness of ozone that is less than 200 Dobson Units (DUs). The information on this chart comes from ten years of ESA satellite observations, first from the Global Ozone Monitoring Experiment (GOME) instrument on ERS-2, and now from its successor, Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY), on Envisat.