A burst of protons from the Sun in 1859 destroyed several times more ozone in Earth's atmosphere than did a 1989 solar flare that was the strongest ever monitored by satellite, a new analysis finds.
When energetic protons from the Sun penetrate Earth's stratosphere, they ionize and dissociate nitrogen and oxygen molecules, which then form ozone-depleting nitrogen oxides.
Thomas et al. developed a scale factor between known nitrate enhancements from recent solar proton events. By using data on nitrate enhancements in Greenland ice cores following the September 1859 burst, they used the scale factor to determine that the total energy released by that solar proton event was 6.5 times larger than the amount released in the 1989 event. Models using this energy total showed that 3.5 times more ozone was destroyed in the 1859 episode than in that of 1989.
Because ozone regulates the amount of harmful ultraviolet radiation reaching Earth, the authors emphasized that understanding intense solar proton events will be important to predicting potential damage to the biosphere.
Title: Modeling atmospheric effects of the September 1859 solar flare
Authors: B. C. Thomas: Department of Physics and Astronomy, Washburn University, Topeka, Kansas, U.S.A.; C. H. Jackman: Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, U.S.A.; A. L. Melott: Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas, U.S.A.
Source: Geophysical Research Letters (GRL) paper 10.1029/2006GL029174, 2007
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