The Plasmaspheric Electron Content Variations During Geomagnetic Storms
Location
Yosemite National Park
Start Date
2-10-2014 7:25 PM
End Date
2-10-2014 7:40 PM
Description
Specification and forecasting of the upper atmosphere plasma distribution is fundamental for mitigation of space weather effects for radio propagation and GNSS applications. The characteristics of the Earth atmosphere ionized part are responding on variations of solar and magnetic activity. Now the GPS measurements are used by the scientific community for the Earth’s upper atmosphere studies. The height of GPS orbits is about 20,200 km above the Earth’s and most part of the propagation path of a radio signal from a satellite to ground-based GPS receiver is mainly within the plasmasphere. As the electron densities in the plasmasphere (PEC) are several orders of less than in the ionosphere (IEC) the plasmasphere is often ignored at analysis of GPS TEC data. But under certain conditions such low solar activity and geomagnetic disturbances the PEC contribution to the GPS TEC can become significant. In the given study the contribution of PEC to the GPS TEC was estimated from the simultaneous measurements of GPS TEC and IEC. The IEC was retrieved as a result of integration of ionospheric electron density profiles (EDPs). For this aim we used EDPs derived from satellite radio occultation (RO) and ground-based radio-physical measurements. The PEC variations during strong geomagnetic storms at November 2004 were estimated by combining of mid-latitude Kharkov ISR observations and GPS TEC data. The comparison between two independent measurements was performed by analysis of the height-temporal distribution for specific point corresponded to the mid-latitudes of Europe. Percentage contribution of PEC to GPS TEC indicated the clear dependence from the time with maximal values (>70%) during night-time and smaller values (30-45%) during day-time for weak disturbance and quite time and rather high values during strong negative storm (up to 90%) with small changes in time. With similar way we analyzed of ionospheric/plasmaspheric effects of October 11, 2008 geomagnetic storm that occurred on background of the extended solar minimum conditions. For this case we used combining of GNSS and FC3/COSMIC RO measurements. It was observed the strong TEC increasing over European region. Peak electron density (Ne) and F2 maximum height increased simultaneously in comparison with the quiet day. The most pronounced effect of the Ne increase occurred at the altitude ~350 km and considerable at the altitudes >400 km. That illustrated the modification of the topside part of the ionosphere and redistribution of TEC/IEC/PEC ratio. These changes can be explained by the competing effects of electric fields and winds which tend to raise the layer to the region with lower loss rate and movement of ionospheric plasma to protonosphere.
The Plasmaspheric Electron Content Variations During Geomagnetic Storms
Yosemite National Park
Specification and forecasting of the upper atmosphere plasma distribution is fundamental for mitigation of space weather effects for radio propagation and GNSS applications. The characteristics of the Earth atmosphere ionized part are responding on variations of solar and magnetic activity. Now the GPS measurements are used by the scientific community for the Earth’s upper atmosphere studies. The height of GPS orbits is about 20,200 km above the Earth’s and most part of the propagation path of a radio signal from a satellite to ground-based GPS receiver is mainly within the plasmasphere. As the electron densities in the plasmasphere (PEC) are several orders of less than in the ionosphere (IEC) the plasmasphere is often ignored at analysis of GPS TEC data. But under certain conditions such low solar activity and geomagnetic disturbances the PEC contribution to the GPS TEC can become significant. In the given study the contribution of PEC to the GPS TEC was estimated from the simultaneous measurements of GPS TEC and IEC. The IEC was retrieved as a result of integration of ionospheric electron density profiles (EDPs). For this aim we used EDPs derived from satellite radio occultation (RO) and ground-based radio-physical measurements. The PEC variations during strong geomagnetic storms at November 2004 were estimated by combining of mid-latitude Kharkov ISR observations and GPS TEC data. The comparison between two independent measurements was performed by analysis of the height-temporal distribution for specific point corresponded to the mid-latitudes of Europe. Percentage contribution of PEC to GPS TEC indicated the clear dependence from the time with maximal values (>70%) during night-time and smaller values (30-45%) during day-time for weak disturbance and quite time and rather high values during strong negative storm (up to 90%) with small changes in time. With similar way we analyzed of ionospheric/plasmaspheric effects of October 11, 2008 geomagnetic storm that occurred on background of the extended solar minimum conditions. For this case we used combining of GNSS and FC3/COSMIC RO measurements. It was observed the strong TEC increasing over European region. Peak electron density (Ne) and F2 maximum height increased simultaneously in comparison with the quiet day. The most pronounced effect of the Ne increase occurred at the altitude ~350 km and considerable at the altitudes >400 km. That illustrated the modification of the topside part of the ionosphere and redistribution of TEC/IEC/PEC ratio. These changes can be explained by the competing effects of electric fields and winds which tend to raise the layer to the region with lower loss rate and movement of ionospheric plasma to protonosphere.