Interhemispheric Asymmetry in the High-Latitude Neutral Density Variations During the 13-14 March 2022 Storm

Area of Science:

• Space Physics
• Atmospheric Science
• Geophysics

Background:

• Intense space weather events, such as geomagnetic storms, significantly impact Earth's upper atmosphere.
• Accurate modeling of neutral mass density variations is crucial for satellite operations and understanding atmospheric dynamics.

Purpose of the Study:

• To investigate the nature and origin of high-latitude neutral mass density anomalies (HDAs) during the recovery phase of the March 2022 storm.
• To analyze the interhemispheric asymmetries (IHAs) in these density variations and their relationship with energy deposition and thermospheric conditions.

Main Methods:

• Utilizing satellite observations to detect neutral mass density spikes at high latitudes.
• Employing the Global Ionospheric Thermosphere Model (GITM) for accurate simulation and analysis of the observed phenomena.
• Investigating the correlation between HDAs, Joule heating, and thermospheric background conditions.

Main Results:

• Detection of intense high-latitude neutral mass density spikes (HDAs) at approximately 500 km in both hemispheres during the storm's recovery phase.
• GITM simulations confirmed HDAs as significant features in high-latitude neutral density, originating from transpolar traveling atmospheric disturbances triggered on the dawn side.
• Significant interhemispheric asymmetries (IHAs) were identified in the magnitude, speed, and direction of HDAs, linked to asymmetries in Joule heating and thermospheric conditions.

Conclusions:

• HDAs are key features of storm-time high-latitude neutral density variations.
• Transpolar traveling atmospheric disturbances initiated on the dawn side are responsible for generating HDAs.
• Interhemispheric asymmetries in HDAs are driven by asymmetries in energy deposition and background thermospheric conditions, providing a dynamic perspective on space weather impacts.