Opposite hemispheric asymmetries during the ionospheric storm of 29–31 August 2004

By making use of multiple ground-based and spaceborne instruments, we study ionospheric and thermospheric behavior during the moderately intense geomagnetic storm of 29–31 August 2004 (minimum Dst excursion of ?128?nT). Although this storm was far from the strongest in solar cycle 23, it provoked quite interesting effects in the ionosphere, such...