Projet de recherche BL/33/SA1 (Action de recherche BL)
DESCRIPTION DU PROJET
The solar UV radiation interacts with the Earth's neutral upper atmosphere (thermosphere) to form an ionized layer called the ionosphere (60 to ~1000 km altitude) while the geomagnetic field links this to the overlying plasmasphere (1000-20000 km). The ionosphere-plasmasphere system (I/Ps) contains negative electrons and positive ions. In that frame, space weather science studies the physical processes beginning at the Sun and causing fluctuations in the I/Ps behaviors.
Better modelling and understanding of the I/Ps is required for scientific and public practical applications using electromagnetic wave signals reflecting on or passing through this layer. This is the case for the Global Navigation Satellite Systems (GNSS, i.e. GPS, GLONASS, Galileo) as well as for spacecraft designers/operators who need precise knowledge of the electron density distribution. The variation of the electron content in the I/P system) depends on (1) solar activity level and the solar zenith angle; (2) the neutral thermospheric composition, (3) the geomagnetic activity, and (5) secondary phenomena (e.g. thermospheric winds, electromagnetic drift, particle precipitation in the aurora …).
While the I/Ps is well monitored and characterised at North low- and mid-latitudes, there is a lack over African continent and polar regions.
The scientific goal of this project is to provide inter-hemispheric comparison of the I/Ps implying:
- A characterisation of the climatological behaviour of the Total Electron Content (TEC) in the I/Ps, over European, South African, Arctic and Antarctica regions.
- Identification of mechanisms that regulate inter-hemispheric differences, asymmetries & commonalities in the I/Ps from low to high-latitudes.
- A study of the different responses of the I/Ps during extreme solar events and induced geomagnetic storms in the two hemispheres
-A separation of the ionospheric and plasmaspheric contribution to the TEC.
To estimate the TEC at different locations on the Earth, the consortium will use GNSS data from available networks (i.e. national, continental, international). The results obtained from the different software developed will be compared at the two institutes to exchange respective knowledge on I/Ps TEC estimation. Then, the physical interpretation will be done through sharing our expertise with each other. An important training component includeds training &exchange of postgraduate students.
The aim of the BEZA-COM project is contribute via structured exchanges among partners to the actual important scientific questions addressed by the International Steering Committee of the Scientific Committee on Antarctic Research (ISC-SCAR): “What are the differences in the inter-hemispheric conjugacy between the ionosphere and that in the lower, middle and upper atmospheres, and what causes those differences?” (Kennicutt, et al., 2014).
