Effects of Rayleigh-Taylor instability and ionospheric plasma bubbles on the global navigation satellite System signal

Abstract

Ionospheric disturbances induced by various natural (e.g., earthquakes, volcanic eruption, thunderstorms, meteorite showers, solar eclipses) or anthropogenic (e.g., nuclear explosions, launching of space shuttles) processes can be detected through change in Total Electron Content (TEC) in the F-layer. These ionospheric perturbations can be captured by worldwide expanding geodetic (GNSS) networks, mainly during the day time, when the solar radiation ionizes the air molecules. However, during post-sunset period, strong ionospheric irregularities (known as Equatorial Plasma Bubbles, EPBs) develop due to the classical configuration for the Rayleigh-Taylor (R-T) instability that diffracts navigation and communication signals. Here we use various instances of ionospheric disturbances triggered by natural processes (e.g., earthquakes and volcanic eruption), in the recent decade to investigate the spatiotemporal and seasonal effects of ionospheric irregularities on the GNSS signals. Our study suggests that in the low-latitudinal region (e.g., Sumatra, Mexico), such ionospheric irregularities can mask the ionospheric perturbations due to the higher production rate of EPBs. Hence detection of such co-seismic TEC anomaly becomes difficult. However, in the high-latitudinal region (e.g., Iceland, Alaska), due to the lower production rate of EPBs, ambient ionospheric irregularities are insignificant and hence coseismic TEC anomalies can be captured even during night time. We argue that the production rate of EPBs further depends upon seasonal and longitudinal parameters on the globe.