据介绍，太阳粒子事件(SPEs)是来自太阳大气的高能粒子的短暂爆发，被广泛认为对现代社会构成重大经济风险。大多数SPEs相对较弱，对地球环境的影响较小，但历史记录中包含了更强的SPEs，它们有可能改变大气化学，影响气候和生物生命。当保护地球的地磁场较弱时，比如在过去的地磁偏移或地磁倒转期间，这种强烈的SPEs的影响会严重得多。
研究团队利用大气—海洋—化学—气候模式SOCOL3-MPIOM和辐射传输模式LibRadtran，模拟了不同地磁场强度下极端SPE对大气化学和地表辐射变化的影响。在目前的地磁条件下，极端的SPE会增加极地平流层和中间层中的NOx浓度，导致温带平流层臭氧减少，持续约一年。
相反，如果没有地磁场，整个大气中的NOx就会大量增加，导致平流层臭氧在数年内严重耗损。由此产生的地面紫外线(UV)辐射将保持高水平长达6年，导致紫外线指数增加20%至25%，太阳引起的DNA损伤率增加40%至50%。过去极端SPE进化的潜在影响仍然是一个重要问题，而它们在现代条件下对人类健康构成的风险仍然被低估。
附：英文原文
Title: Global impacts of an extreme solar particle event under different geomagnetic field strengths
Author: Arsenovic, Pavle, Rozanov, Eugene, Usoskin, Ilya, Turney, Chris, Sukhodolov, Timofei, McCracken, Ken, Friedel, Marina, Anet, Julien, Simi, Stana, Maliniemi, Ville, Egorova, Tatiana, Korte, Monika, Rieder, Harald, Cooper, Alan, Peter, Thomas
Issue&Volume: 2024-7-1
Abstract: Solar particle events (SPEs) are short-lived bursts of high-energy particles from the solar atmosphere and are widely recognized as posing significant economic risks to modern society. Most SPEs are relatively weak and have minor impacts on the Earth’s environment, but historic records contain much stronger SPEs which have the potential to alter atmospheric chemistry, impacting climate and biological life. The impacts of such strong SPEs would be far more severe when the Earth’s protective geomagnetic field is weak, such as during past geomagnetic excursions or reversals. Here, we model the impacts of an extreme SPE under different geomagnetic field strengths, focusing on changes in atmospheric chemistry and surface radiation using the atmosphere–ocean–chemistry–climate model SOCOL3-MPIOM and the radiation transfer model LibRadtran. Under current geomagnetic conditions, an extreme SPE would increase NOx concentrations in the polar stratosphere and mesosphere, causing reductions in extratropical stratospheric ozone lasting for about a year. In contrast, with no geomagnetic field, there would be a substantial increase in NOx throughout the entire atmosphere, resulting in severe stratospheric ozone depletion for several years. The resulting ground-level ultraviolet (UV) radiation would remain elevated for up to 6 y, leading to increases in UV index up to 20 to 25% and solar-induced DNA damage rates by 40 to 50%. The potential evolutionary impacts of past extreme SPEs remain an important question, while the risks they pose to human health in modern conditions continue to be underestimated.
DOI: 10.1073/pnas.2321770121
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2321770121