IGRF-14 secular variation prediction from core surface flow acceleration

Area of Science:

• Geophysics
• Earth Sciences
• Space Physics

Background:

• The International Geomagnetic Reference Field (IGRF) requires regular updates, including estimates of geomagnetic secular variation (SV).
• Previous models have limitations in predicting SV for intermediate years between updates.
• Recent observations suggest periodic behavior in core surface flow acceleration, offering new predictive potential.

Purpose of the Study:

• To develop and submit a candidate model for geomagnetic secular variation (SV) for the 2025-2030 period for the 14th generation IGRF.
• To forecast SV by analyzing the periodic behavior of core surface flow acceleration.
• To validate the predictive capability of the new methodology against previous IGRF iterations.

Main Methods:

• Obtained advective core surface flow models from CHAMP and Swarm satellite data (2001-2024).
• Calculated flow acceleration coefficients and fitted them with sinusoidal functions for future extrapolation.
• Integrated acceleration time series to obtain core flow coefficients and predict advected SV.

Main Results:

• The methodology, validated using CHAMP data, outperformed previous IGRF iterations.
• The Swarm-based model forecasts SV for IGRF-14, predicting geomagnetic jerks in 2024 (Equatorial Pacific) and 2028 (central Africa).
• The model demonstrates potential improvements by incorporating periodic behavior in SV prediction.

Conclusions:

• The proposed method, incorporating periodic core surface flow acceleration, offers a promising approach for geomagnetic secular variation forecasting.
• The model's ability to predict geomagnetic jerks highlights its potential for more accurate IGRF updates.
• This approach may enhance the prediction of SV for future IGRF generations.