HAO Colloquium - Iurii Cherniak, UCAR/COSMIC

GNSS as a Global Observing System for Ionospheric Study

Techniques based on the transionospheric radio waves propagation, in particular Global Navigation Satellite Systems (GNSS), has been effectively used during several decades for ionospheric climatology research as well as for monitoring and study of main parameters of ionospheric plasma disturbances. The number of the ground-based receivers within the global and regional GNSS networks grew significantly from several hundred worldwide in the 1990s to more than 6000 stations today. Many of operated Low-Earth-Orbit satellites are also equipped with dual-frequency GNSS receivers and gives possibilities to estimate topside ionosphere plasma density and detect the ionospheric irregularities signatures at high altitudes. Ground-based GNSS networks and LEO GPS provide continuous measurements of navigation signals parameters, that allows to consider these facilities as a global observatory for permanent monitoring of ionospheric plasma density spatial distribution and its dynamics. We present results demonstrating advantages of using dense ground-based GNSS networks and LEO GPS observations for investigation of ionospheric responses on Space Weather drivers and focus on representative case studies during the 2015 severe geomagnetic storms. In this report, we investigate signatures of the large-scale traveling ionospheric disturbances (LSTIDs) recognized in the ground-based total electron content (TEC) and storm-induced ionospheric plasma density irregularities caused by auroral particles precipitations and plasma gradients associated with SED/TOI (storm-enhanced density / tongue of ionization) formation. Also, we present recent results of GNSS TEC analysis of the ionosphere’s response to the 21 August 2017 solar eclipse.

Date and time: 
Wednesday, February 21, 2018 - 2:00pm to 3:00pm