Multi-frequency investigation of height-dependent drift variability of the sporadic E (Es) layers in the polar region using Canadian Advanced Digital Ionosonde

Abstract

Ionospheric plasma motion and density gradients affect radio wave propagation by causing irregularities that lead to rapid fluctuations and alter signal characteristics. While F - region drift (convection) is well understood in the Polar Cap, plasma drift in the lower ionosphere, especially the E region (90-150 km altitude), remains poorly understood due to limited measurements. To address this gap, we analyzed ionospheric motion during Sporadic E conditions to investigate the morphology and variability of drift in the 100-150 km region of the polar cap. The three components of drift (vertical, zonal, meridional) over Pond Inlet (72.70°N, 77.95°W) were studied using Doppler interferometry with the Canadian Advanced Digital Ionosonde (CADI). Drift measurements at 2.73, 4, 5, and 6 MHz were analyzed. Gaussian fits showed no significant differences for 2.73-5 MHz, while 6 MHz data exhibited greater variability (up to 500 m/s). Case studies revealed factors influencing E-region drift.