ELF Q-bursts from African Squall Lines

A number of large amplitude ELF transient signals (Q-bursts) are documented at multiple sites around the world (Japan, Hungary, Israel and USA) in association with westward moving mesoscale convective systems (MCSs) in West Africa during the African Monsoon and Multidisciplinary Analysis campaign in 2006. Some of these bursts are associated with red sprites first observed from ground-based measurement in Africa. Using MIT Doppler radar and electric field measurements locally installed in Niamey, we investigate quantitatively the meteorological conditions responsible for generating these exceptionally large Q-bursts. Detailed meteorological information is provided from radar such as the spatio-temporal evolution of radar echo, while the electrical properties oflarge Q-bursts (e.g. charge moment charge (CMC)) are experimentally derived by using the remote-sensing method taking into account the theory for the earth-ionoshere wave guide. Furthermore, detailed propagation characteristics of Q-bursts and their effect on the location and remotely derived accuracy of the CMC will be discussed by comparing the results from multi ELF stations under different ionospheric conditions such as day-night asymmetry and the ionospheric terminator lines. Preliminary results from similar campaign in 2007 in Niger will also be presented to be compared with those in 2006.