Accurate forecasting of the arrival time and arrival speed of coronal mass ejections (CMEs) is an unsolved problem in space weather research. In this study, a comparison of the predicted arrival times and speeds for each CME based, independently, on the inputs from the two STEREO vantage points is carried out. We perform hindcasts using ELlipse Evolution model based on Heliospheric Imager observations (ELEvoHI) ensemble modeling. An estimate of the ambient solar wind conditions is obtained by the Wang‐Sheeley‐Arge/Heliospheric Upwind eXtrapolation (WSA/HUX) model combination that serves as input to ELEvoHI. We carefully select 12 CMEs between February 2010 and July 2012 that show clear signatures in both STEREO‐A and STEREO‐B HI time‐elongation maps, that propagate close to the ecliptic plane, and that have corresponding in situ signatures at Earth. We find a mean arrival time difference of 6.5 h between predictions from the two different viewpoints, which can reach up to 9.5 h for individual CMEs, while the mean arrival speed difference is 63 km s⁻¹. An ambient solar wind with a large speed variance leads to larger differences in the STEREO‐A and STEREO‐B CME arrival time predictions (cc = 0.92). Additionally, we compare the predicted arrivals, from both spacecraft, to the actual in situ arrivals at Earth and find a mean absolute error of 7.5 ± 9.5 h for the arrival time and 87 ± 111 km s⁻¹ for the arrival speed. There is no tendency for one spacecraft to provide more accurate arrival predictions than the other.

中文翻译：

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如果ELEvoHI CME的到达预测为何基于STEREO-A或STEREO-B太阳球成像仪观测值而有所不同？

精确预测日冕物质抛射（CME）的到达时间和到达速度是空间天气研究中尚未解决的问题。在这项研究中，每个CME的预计到达时间和速度的比较是独立地基于来自两个STEREO有利位置的输入进行的。我们使用基于日球成像仪观测（ELEvoHI）整体建模的椭圆演化模型进行后播。通过Wang-Sheeley-Arge / Heliospheric逆风外推（WSA / HUX）模型组合获得了对太阳风周围环境的估计，该模型组合用作ELEvoHI的输入。我们精心选择了2010年2月至2012年7月之间的12个CME，它们在STEREO-A和STEREO-B HI时间伸长图中都显示出清晰的特征，它们在黄道平面附近传播，并且在地球上具有相应的原位标记。从两个不同的观点，我们发现预测之间的平均到达时间差为6.5 h，单个CME的平均到达时间差可以达到9.5 h，而平均到达速度差为63 km s^-1。速度变化较大的环境太阳风导致STEREO‐A和STEREO‐B CME到达时间预测的差异更大（cc  = 0.92）。此外，我们将两个航天器的预计到达量与实际到达地球的位置进行了比较，发现到达时间的平均绝对误差为7.5±9.5 h，到达速度的平均绝对误差为87±111 km s ^-1。一种航天器没有比另一种航天器提供更准确的到达预测的趋势。