Spaceborne GNSS-R for High Latitude Ionospheric TEC Disturbance Observations

This paper presents an innovative approach to observe the slant total electron content (TEC) structures from coherently reflected Global Navigation Satellite System (GNSS) signals collected by Spire Global CubeSats over the Arctic region. The high latitudes offer the pathway for solar and geomagnetic disturbances to impact the ionosphere. The magnitude of the GNSS-reflectometry (GNSS-R) derived TEC disturbance is quantified by the rate of TEC index (ROTI). A case study for a severe geomagnetic storm that occurred on May 12, 2021, is presented in this paper. The objective of the study is to demonstrate that GNSS-R measurement has the potential to offer a new ionosphere data source at high latitudes to fill the void of observations due to sparsity of GNSS receivers over oceans, inaccessible terrains, and GNSS satellite orbit inclination constraint.