B2 Thickness Parameter Response to Equinoctial Geomagnetic Storms

Area of Science:

• Space Physics
• Ionospheric Physics
• Geophysics

Background:

• Empirical models often define ionospheric thickness parameters using ionogram characteristics.
• The NeQuick model uses the B2 parameter, representing F2 bottomside electron density profile thickness, derived from an inflection point below the F2 layer peak.
• Understanding ionospheric responses to geomagnetic storms is crucial for space weather prediction.

Purpose of the Study:

• To investigate the effects of geomagnetic storms on the B2 thickness parameter.
• To analyze the temporal relationship between the B2 parameter, vertical total electron content (VTEC), and maximum electron density (NmF2) during storm events.
• To assess the potential of incorporating the B2 parameter into empirical models for improved storm-time predictions.

Main Methods:

• Analysis of three major equinoctial geomagnetic storms (March 17, 2013; October 2, 2013; March 17, 2015).
• Utilized GNSS-derived VTEC and NmF2 data from manually scaled ionograms across 20 stations in middle and low latitudes.
• Examined B2 parameter variations before, during, and after storm events in Asian, Euro-African, and American longitude sectors.

Main Results:

• Observed two primary B2 responses post-storm onset: a peak preceding VTEC/NmF2 increases (~60% of cases) and fluctuations linked to VTEC/NmF2 decreases (~25% of cases).
• The B2 parameter consistently reacted earlier than NmF2 and VTEC following storm onset across all analyzed locations.
• Storm-induced B2 behavior was correlated with dominant factors associated with positive and negative storm effects.

Conclusions:

• The B2 thickness parameter exhibits significant sensitivity to geomagnetic storm disturbances.
• Experimental B2 data shows a precursor response to changes in VTEC and NmF2 during storms.
• Incorporating the B2 parameter into empirical models like NeQuick could enhance their capability to model extreme ionospheric conditions during space weather events.