The project is funded by DFG within the priority program 1788 ‘DynamicEarth’ http://www.spp-dynamicearth.de.
Coupling processes between the ionosphere and the neutral atmosphere play an important role for the dynamics of the upper atmosphere. Recent progress in understanding the related processes has been achieved since low-Earth orbiting satellites provide continuous accurate measurements of thermospheric and ionospheric parameters like mass density, zonal winds and electron density profiles, respectively.
Within this project, we plan to observe the global sporadic E occurrence in quantity and also in its quality. The study will be based on GPS radio occultation measurements performed by the satellites CHAMP, GRACE, TerraSAR-X, TanDEM-X and FORMOSAT-3/COSMIC. Since the launch of the CHAMP satellite in 2000, there are currently more than 5 million of radio occultation profiles available. This fact allows to investigate sporadic E properties in a high spatial resolution as well as to perform statistical trend analysis of sporadic E occurrence. It is planned to extent the currently used sporadic E detection algorithm in order to receive additional information on sporadic E intensities.
Global information on sporadic E layer intensities are not available yet and will be provided for the first time from radio occultation measurements. It can be used to look for changes in the sporadic E layer behavior itself and also in the connection between sporadic E parameters and other geophysical parameters like the decreasing strength of Earth’s magnetic field and solar cycle dependence of atmospheric tides, meteor influx and ionospheric phenomena, as e.g., equatorial plasma depletions.
Arras, C., J. Wickert, C. Jacobi, S. Heise, G. Beyerle, and T. Schmidt (2008): A global climatology of ionospheric irregularities derived from GPS radio occultation, Geophys. Res. Lett., 35, L14,809, doi:10.1029/2008GL034158.
Arras, C., C. Jacobi, and J. Wickert (2009): Semidiurnal tidal signature in sporadic E occurrence rates derived from GPS radio occultation measurements at higher midlatitudes, Ann. Geophys., 27, 2555–2563.
Arras, C., C. Jacobi, J. Wickert, S. Heise, and T. Schmidt (2010): Sporadic E signatures revealed from multi-satellite radio occultation measurements, Adv. in Radio Sci., 8, 225–230, doi:10.5194/ars-8-225-2010.
Arras, C. (2010): A global Survey of Sporadic E Layers based on GPS Radio Occultations by CHAMP, GRACE and FORMOSAT-3/COSMIC, PhD thesis, University of Leipzig.
Arras, C., J. Wickert, C. Jacobi, G. Beyerle, S. Heise, and T. Schmidt (2012): Global sporadic E layer characteristics obtained from GPS radio occultation measurements, Springer, F.-J. Lübken, Dordrecht, The Netherlands.