On the probability of occurrence of extreme space weather events
On the probability of occurrence of extreme space weather events
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DOI：
10.1029/2011sw000734
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发表时间：
2012-02-23
影响因子：
3.7
通讯作者：
Riley, Pete
中科院分区：
文献类型：
--
作者：
Riley, Pete
1859年卡林顿事件等极端空间天气事件由于其罕见性而难以研究，其发生率难以估计，对未来特定事件的预测几乎是不可能的。此外，事件可能相对于一个参数是极端的，但相对于其他参数是正常的。在这项研究中，我们分析了空间天气事件的严重性（耀斑强度，日冕物质抛射速度，Dst和从硝酸盐记录推断的> 30 MeV质子注量）的几个措施，以估计极端事件发生的概率。通过表明发生频率与事件严重程度的幂成反比，并假设这种关系在更高的量级上成立，我们就能够估计出未来某个时间间隔内发生的事件大于某个标准的概率。例如，在未来十年内发生另一个卡林顿事件（基于Dst < -850 nT）的概率类似于12%。我们还确定并解决了这种方法的几个限制。特别是，我们假设时间平稳性，因此，长期空间气候变化的影响不被考虑。虽然这种技术不能用来预测特定的事件，但它最终可能对概率预测有用。引用：Riley，P.（2012），关于极端空间天气事件发生的概率，空间天气，10，S 02012，doi：10.1029/2011 SW 000734。
By virtue of their rarity, extreme space weather events, such as the Carrington event of 1859, are difficult to study, their rates of occurrence are difficult to estimate, and prediction of a specific future event is virtually impossible. Additionally, events may be extreme relative to one parameter but normal relative to others. In this study, we analyze several measures of the severity of space weather events (flare intensity, coronal mass ejection speeds, Dst, and > 30 MeV proton fluences as inferred from nitrate records) to estimate the probability of occurrence of extreme events. By showing that the frequency of occurrence scales as an inverse power of the severity of the event, and assuming that this relationship holds at higher magnitudes, we are able to estimate the probability that an event larger than some criteria will occur within a certain interval of time in the future. For example, the probability of another Carrington event (based on Dst < -850 nT) occurring within the next decade is similar to 12%. We also identify and address several limitations with this approach. In particular, we assume time stationarity, and thus, the effects of long-term space climate change are not considered. While this technique cannot be used to predict specific events, it may ultimately be useful for probabilistic forecasting. Citation: Riley, P. (2012), On the probability of occurrence of extreme space weather events, Space Weather, 10, S02012, doi:10.1029/2011SW000734.