Underutilized Spaceborne GPS Observations for Space Weather Monitoring

Abstract

Many of currently operated low Earth orbit satellites, in particular Earth observing meteorological missions, are equipped with dual‐frequency Global Positioning System (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 underutilized spaceborne GPS measurements for Space Weather activity monitoring by specification of storm‐induced ionospheric plasma density irregularities at different altitudinal domain of the topside ionosphere. We have analyzed a dynamical response of the high‐latitude topside ionosphere to the intense geomagnetic storm of 19–21 December 2015 using up‐looking GPS measurements on board Swarm and Meteorological Operational satellite (MetOp) missions, flying at altitudes of ~500 km and ~835 km, respectively. For the first time, GPS observations on board 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 Super Dual Auroral Radar Network 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 and the polar tongue of ionization structures, which is the first direct observation of the storm‐enhanced density/tongue of ionization structure in the plasmaspheric TEC.

Longitudinal and Seasonal Variability of Equatorial Ionospheric Irregularities and Electrodynamics

“…During the time (00:40–00:49 UT or 21:08–21:18 LT) when the topside ROTI and in situ density detected significant irregularities, the ground‐based ROTIs from all GPS (third panel from top) and GLONASS (bottom panel) satellites show significantly strong values during the time (shown between the two dashed vertical lines) when the topside ROTI shown strong value, indicating that irregularity penetrated well above SWARM‐A and SWARM‐C orbit height (460 km). All these demonstrate that the topside ROTI provide valuable information about irregularity distribution in the topside ionosphere (Zakharenkova & Cherniak, ). Therefore, it can be used to characterize the longitudinal variabilities of irregularities in the topside ionosphere.…”

“…We utilized the massive data set from GPS receivers on board LEO satellites and estimated the bubble distribution in the topside ionosphere by calculating ROTI from the topside TEC measurements, using the same technique that we applied on the ground‐based GNSS TEC (Zakharenkova & Cherniak, ). The topside TECs are estimated from the measurements of GPS receivers on board LEO satellites with upward looking antenna.…”

When Plasma Streams Tie up Equatorial Plasma Irregularities with Auroral Ones

“…The maps of detrended ΔTEC can be used to study signatures of the medium‐scale and large‐scale traveling ionospheric disturbances (MSTIDs/LSTIDs) propagation (Otsuka et al, ; Tsugawa et al, ; Zakharenkova et al, ). Additionally, we utilize data provided by the Swarm satellites operating at ~465‐ to 515‐km orbit altitude: (1) in situ electron density (Ne) from Langmuir probe instrument, (2) GPS ROT (rate of TEC) from the onboard Swarm GPS receiver measurements (Zakharenkova & Cherniak, ), (3) field‐aligned currents (FACs) estimated from the Swarm magnetometer data (Lühr et al, ), as well as in situ ion density (Ni) and horizontal ion drifts measured onboard DMSP (Defense Meteorological Satellite Program) satellites at ~845‐km altitude.…”

Features of Storm‐Induced Ionospheric Irregularities From Ground‐Based and Spaceborne GPS Observations During the 2015 St. Patrick's Day Storm

“…The satellites have a GPS receiver with eight multifrequency channels that can track up to eight GPS satellites at 1 Hz. These spaceborne up‐looking GPS measurements represent a unique data source to detect directly ionospheric irregularities in the topside ionosphere, especially during space weather events (Zakharenkova & Cherniak, ). We processed the spaceborne GPS observations to derive the ROT/ROTI values that were further analyzed for the ionospheric irregularities detection in the topside ionosphere (above ~500‐km altitude) along the Swarm‐A and Swarm‐B satellites orbits.…”