Testing the current paradigm for space weather prediction with heliospheric imagers
Testing the current paradigm for space weather prediction with heliospheric imagers
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DOI：
10.1002/2017sw001609
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发表时间：
2017-06
期刊：
影响因子：
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通讯作者：
L. Barnard;C. Koning;C. Scott;M. Owens;J. Wilkinson;J. Davies
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文献类型：
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作者：
L. Barnard;C. Koning;C. Scott;M. Owens;J. Wilkinson;J. Davies
对地球空间中四次日冕物质抛射 (CME) 到达的预测是通过使用三个 CME 几何模型与 CME 阻力建模相结合来生成的，并使用可用的日冕仪和日光层成像仪数据约束这些模型。这些预测的有效性是通过与空间天气预报中心 (SWPC) 对这些相同事件的 MHD 数值预报进行比较来评估的。研究发现，这种预测技术在统计上有意义的水平上无法优于标准 SWPC 预测。我们测试了调和平均、自相似展开和椭圆演化几何模型，发现至少对于这些事件，模型之间的差异小于观测误差。我们提出了一种在日光层成像仪视场中表征日冕物质抛射锋面的新方法，利用参与太阳风暴观察项目的公民科学家的分析，并且我们证明，与专家分析所研究事件的伸长时间图所获得的结果相比，这提供了更准确的日冕物质抛射锋面表示。独立于 STEREO-A 和 STEREO-B 日光层成像仪数据估计的 CME 运动学的比较揭示了观测误差和模型假设无法解释的不一致之处。我们认为，这些观察结果意味着日冕物质抛射几何模型的假设通常是无效的，并质疑它们在空间天气预报中的实用性。这些结果表明需要继续开发更先进的技术，以更好地利用日光层成像仪观测进行空间天气预报。
Predictions of the arrival of four coronal mass ejections (CMEs) in geospace are produced through use of three CME geometric models combined with CME drag modeling, constraining these models with the available Coronagraph and Heliospheric Imager data. The efficacy of these predications is assessed by comparison with the Space Weather Prediction Center (SWPC) numerical MHD forecasts of these same events. It is found that such a prediction technique cannot outperform the standard SWPC forecast at a statistically meaningful level. We test the Harmonic Mean, Self‐Similar Expansion, and Ellipse Evolution geometric models, and find that, for these events at least, the differences between the models are smaller than the observational errors. We present a new method of characterizing CME fronts in the Heliospheric Imager field of view, utilizing the analysis of citizen scientists working with the Solar Stormwatch project, and we demonstrate that this provides a more accurate representation of the CME front than is obtained by experts analyzing elongation time maps for the studied events. Comparison of the CME kinematics estimated independently from the STEREO‐A and STEREO‐B Heliospheric Imager data reveals inconsistencies that cannot be explained within the observational errors and model assumptions. We argue that these observations imply that the assumptions of the CME geometric models are routinely invalidated and question their utility in a space weather forecasting context. These results argue for the continuing development of more advanced techniques to better exploit the Heliospheric Imager observations for space weather forecasting.