Ionosphere Sounding in the Central Arctic: Preliminary Results of the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) Expedition

Abstract

We report on an experiment conducted during the expedition of the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) in 2019 and 2020. Signals of global navigation satellite systems (GNSS) were recorded during 12 months aboard the German research icebreaker Polarstern that drifted with a sea ice floe over the Arctic Ocean. Here, we focus on an ionosphere sounding experiment and present preliminary results from a 5 month period in the central Arctic (.858 N). Based on the standard deviations of phase samples (phase scintillation index), we found ship-related disturbances and anomalies, indicating space weather impact on GNSS signals. The ship-related disturbances with values up to 0.4 rad, attributed to mast and chimney shadowing, are masked out. Anomalies can be resolved with index values of 0.15 rad to 0.2 rad that are attributed to variations of ionospheric electron density in the cusp region. The baseline of GPS index observations with this shipborne setup lies at ~0.1 rad for elevations >30° and reaches up to 0.17 rad at lowest elevations. This baseline for the drifting ship is significantly higher than the baseline of up to 0.05 rad found for ground-based stations equipped with the same receiver type. We conclude that ionospheric phase scintillation in GNSS signals can be detected from a ship drifting with the Arctic ice. Restrictions due to shadowing and increased noise level of the ship scenario have to be considered.