The Effect of Field Line Tracing Height on Wang-Sheeley-Arge Solar Wind Predictions at Earth
Abstract
(Abridged abstract): A key component of the widely used Wang-Sheeley-Arge model is the tracing of magnetic field lines in the solar corona, as that largely determines the modeled open/closed field regions and in turn the predicted large-scale solar wind structure. We demonstrate that by slightly raising the height from which magnetic field lines are traced from the photosphere (Rsu), we can improve the prediction of solar wind high-speed enhancements (HSEs). We find a higher Rsu produces more accurate estimates of the HSE start time, duration, and peak speed, and enables the detection of HSEs that were missed with the standard Rsu. These improvements are primarily associated with changes in the great-circle angular distance, while the flux tube expansion factors remain largely unchanged. A higher Rsu produces smoother open-field boundaries and reduces small-scale fragmentation within open-field regions. These morphological changes lead to more stable magnetic footpoint mappings and consequently more robust GCD calculations. To assess the statistical relevance of these findings, we extend the analysis to 53 Carrington rotations and perform a multi-metric evaluation of model performance. The results indicate that higher Rsu improves HSE predictions while reducing false alarms. We thus find that the choice of Rsu represents an important and previously underexplored parameter that can help enhance our ambient solar wind modeling and forecasting capabilities.
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BibTeX
@misc{majumdar2026effect,
title = {{The Effect of Field Line Tracing Height on Wang-Sheeley-Arge Solar Wind Predictions at Earth}},
author = {Satabdwa Majumdar and Martin A. Reiss and Pete Riley and Charles N. Arge},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.28274},
eprint = {2610.28274},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.28274},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The Effect of Field Line Tracing Height on Wang-Sheeley-Arge Solar Wind Predictions at Earth
AU - Satabdwa Majumdar
AU - Martin A. Reiss
AU - Pete Riley
AU - Charles N. Arge
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2610.28274
UR - https://arxiv.org/abs/2610.28274
AB - (Abridged abstract): A key component of the widely used Wang-Sheeley-Arge model is the tracing of magnetic field lines in the solar corona, as that largely determines the modeled open/closed field regions and in turn the predicted large-scale solar wind structure. We demonstrate that by slightly raising the height from which magnetic field lines are traced from the photosphere (R_su), we can improve the prediction of solar wind high-speed enhancements (HSEs). We find a higher R_su produces more accurate estimates of the HSE start time, duration, and peak speed, and enables the detection of HSEs that were missed with the standard R_su. These improvements are primarily associated with changes in the great-circle angular distance, while the flux tube expansion factors remain largely unchanged. A higher R_su produces smoother open-field boundaries and reduces small-scale fragmentation within open-field regions. These morphological changes lead to more stable magnetic footpoint mappings and consequently more robust GCD calculations. To assess the statistical relevance of these findings, we extend the analysis to 53 Carrington rotations and perform a multi-metric evaluation of model performance. The results indicate that higher R_su improves HSE predictions while reducing false alarms. We thus find that the choice of R_su represents an important and previously underexplored parameter that can help enhance our ambient solar wind modeling and forecasting capabilities.
ER -