Machine learning for predicting the Bz magnetic field component from upstream in situ observations of solar coronal mass ejections

Abstract

Predicting the Bz magnetic field embedded within ICMEs, also known as the Bz problem, is a key challenge in space weather forecasting. We study the hypothesis that upstream in situ measurements of the sheath region and the first few hours of the magnetic obstacle provide sufficient information for predicting the downstream Bz component. To do so, we develop a predictive tool based on machine learning that is trained and tested on 348 ICMEs from Wind, STEREO-A, and STEREO-B measurements. We train the machine learning models to predict the minimum value of the Bz component and the maximum value of the total magnetic field Bz in the magnetic obstacle. To validate the tool, we let the ICMEs sweep over the spacecraft and assess how continually feeding in situ measurements into the tool improves the Bz prediction. Because the application of the tool in operations needs an automated detection of ICMEs, we implement an existing automated ICME detection algorithm and test its robustness for the time intervals under scrutiny. We find that the predictive tool can predict the minimum value of the Bz component in the magnetic obstacle with a mean absolute error of 3.12 nT and a Pearson correlation coefficient of 0.71 when the sheath region and the first 4 hours of the magnetic obstacle are observed. While the underlying hypothesis is unlikely to solve the Bz problem, the tool shows promise for ICMEs that have a recognizable magnetic flux rope signature. Transitioning the tool to operations could lead to improved space weather forecasting.

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Cited by in corpus (6)

• CMEs and SEPs During November-December 2020: A Challenge for Real-Time Space Weather Forecasting
• Using Solar Orbiter as an upstream solar wind monitor for real time space weather predictions
• Forecasting GICs and geoelectric fields from solar wind data using LSTMs: application in Austria
• Automatic Detection of Interplanetary Coronal Mass Ejections in Solar Wind In Situ Data
• Symbolic Knowledge Extraction from Opaque Predictors Applied to Cosmic-Ray Data Gathered with LISA Pathfinder
• Which Upstream Solar Wind Conditions Matter Most in Predicting Bz within Coronal Mass Ejections