Sensitivity of model estimates of CME propagation and arrival time to inner boundary conditions
Sensitivity of model estimates of CME propagation and arrival time to inner boundary conditions
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CME 传播和到达时间的模型估计对内部边界条件的敏感性
DOI：
10.1002/essoar.10512439.1
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
James L
中科院分区：
文献类型：
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作者：
James L
准确预测日冕物质抛射 (CME) 到达地球对于减轻与社会相关的空间天气风险非常重要。这只有通过对事件进行精确建模才能实现。为此，我们必须了解日冕物质抛射在日光层中的传播，并通过与航天器观测结果的比较来量化模型的性能。对于 2008 年 12 月 12 日面向地球的日冕物质抛射事件，我们使用 HUXt 太阳风模型计算系综，以分析结构化太阳风的日冕物质抛射失真并探索后报到达时间误差 (ATE)。通过强调日冕物质抛射形状对均方根误差 (RMSE) 值的影响，我们表明 NASA STEREO 任务上的日光层成像仪 (HI) 仪器捕获的锋面时间伸长剖面与模拟的日冕物质抛射鼻子和侧面的时间伸长剖面相匹配，因此可用于推断日冕物质抛射纵向范围的细节。然后我们表明，考虑 CME 畸变对于准确估计到达地球的 CME 非常重要。这可以通过使用 HI 数据中多个特征的观测来推断日冕物质抛射演化或将太阳风映射回较低的内边界以允许日冕物质抛射在靠近太阳时发生扭曲来实现。对于研究的事件，我们表明这些方法使 RMSE 降低了 0.726° 和 0.638°，ATE 分别为 1 小时和 3 小时。
Accurately forecasting the arrival of coronal mass ejections (CMEs) at Earth is important to enabling mitigation of the associated space weather risks to society. This is only possible with accurate modelling of the event. To do so, we must understand the propagation of a CME through the heliosphere and quantify the performance of models through comparison with spacecraft observations. For the December 12th 2008 Earth-directed CME event, we compute ensembles using the HUXt solar wind model to analyse CME distortion with a structured solar wind and explore hindcast arrival time error (ATE). By highlighting the impact CME shape has on Root-Mean-Square-Error (RMSE) values, we show that time-elongation profiles of fronts captured by the Heliospheric Imager (HI) instruments onboard NASA’s STEREO mission match those of the modelled CME nose and flank and can therefore be used to infer details of the longitudinal extent of the CME. We then show that accounting for CME distortion is important to enable accurate estimates of the CME arrival at Earth. This can be achieved by either using observations of multiple features in HI data to infer CME evolution or mapping the solar wind back to a lower inner boundary to allow CMEs to be distorted close to the Sun. For the event studied we show that these approaches resulted in reduced RMSEs of 0.726˚and 0.638˚ with an ATE of one hour and three hours respectively.