Worst-Case Scenario of a Solar Particle Storm and its Terrestrial Influence
Solar energetic particles (SEP) affect the Earth's atmosphere and environment, in particular by destroying the ozone layer in the Earth's atmosphere. They also pose technological hazards for satellites and even threaten the health of space and aircraft crew. The strongest observed solar particle storm occurred on 23-Feb-1956. A similar storm now would harm or even kill astronauts if there were some on orbit. The greatest SEP storm known from indirect proxy records covering the whole Holocene (the time after ice age) occurred in 774-775 AD, serving as a worst-case scenario for SEPs. It was 40-50 times stronger than any directly observed SEP event. We have made a systematic analysis of the impacts that such an extreme event can have on the Earth’s atmosphere. Using cosmic ray cascade and chemistry-climate models, we reproduced the observed variability of 10Be cosmogenic isotope around 775 AD in four ice cores from Greenland and Antarctica. We showed that such a severe event is able to perturb the polar stratosphere for at least one year, leading to regional changes in the surface temperature of up to several degrees during northern hemisphere winters.
