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Identify causes of differing prediction skill for EUHFORIA-driven vs L1-driven OpenGGCM across two events

Investigate and identify the reasons why OpenGGCM Dst predictions driven by EUHFORIA outputs outperformed those driven by L1 in situ observations for the September 4–6, 2017 event, whereas the opposite was observed for the July 12, 2012 event, and determine the solar wind and model factors responsible for this difference in skill.

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Background

The paper validates the coupled EUHFORIA–OpenGGCM framework on two CME-driven storms. For the July 12, 2012 event (Event 1), L1-driven inputs slightly outperformed EUHFORIA-driven inputs in reproducing Dst, while for the September 4–6, 2017 event (Event 2), EUHFORIA-driven inputs clearly performed better.

Understanding the causes of these divergent outcomes would inform model configuration, sensitivity to solar wind inputs (e.g., Bz timing and amplitude), and the conditions under which physics-based heliospheric forecasts can yield superior magnetospheric predictions compared to direct L1 measurements.

References

It is not possible to comment on why OpenGGCM predictions were better using EUHFORIA inputs over the actual L1 observations, in Event 2 but not in Event 1.

— Employing the coupled EUHFORIA-OpenGGCM model to predict CME geoeffectiveness (2403.19873 - Maharana et al., 28 Mar 2024) in Section 6 (Summary and Discussion)