Underutilized space-borne GPS observations for Space Weather monitoring
Presenter:
Irina Zakharenkova
Space Radio-Diagnostics Research Center, University of Warmia and Mazury, Poland
COSMIC Project Office, University Corporation for Atmospheric Research, Boulder, USA
Talk
Many of currently operated Low-Earth-Orbit (LEO) satellites, in particular Earth Observing meteorological missions, are equipped with dual-frequency GPS receivers with a zenith-looking antenna for tasks of precise orbit determination and timing. The already existed databases with accumulated raw GPS measurements, as a by-product of satellite missions, can arouse specific interest for ionospheric and space weather community too. We demonstrate potential possibilities and advantages of involving space-borne GPS measurements, both Radio Occultation and upward-looking, for Space Weather activity monitoring by specification of storm-induced ionospheric plasma density irregularities at different altitudinal domain of the ionosphere. We have analyzed a dynamical response of the high-latitude topside ionosphere to the intense geomagnetic storms using upward-looking GPS measurements onboard Swarm and MetOp missions, and GPS RO measurements from COSMIC and GRACE missions. For the first time, GPS observations onboard the meteorological mission MetOp were used to reveal an occurrence of plasma irregularities at altitudes above 835 km. Our results demonstrate that during strong geomagnetic storms the intense plasma density irregularities can occur in the topside ionosphere near ~500 km altitude and can be still persisted above 835 km. Joint analysis of the SuperDARN global convection patterns, ground-based GPS Total Electron Content (TEC) observations and MetOp-derived topside TEC observations confirmed that plasma irregularities above ~835 km coincided with the plasmaspheric/magnetospheric part of the storm-enhanced density (SED) and the polar tongue of ionization (TOI) structures – that is the first direct observation of the SED/TOI structure in the plasmaspheric TEC. Ionospheric contribution of SED/TOI can be effectively estimated by ionospheric plasma density profiles retrieved from GPS RO observations.
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