Propagation of upper atmospheric storm effects towards lower latitudes Original Research Article

It has been suggested that both positive ionospheric storms at middle latitudes and anomalous increases in the neutral thermospheric density at low latitudes are caused by traveling atmospheric disturbances (TADs). Here we test this idea using ionosonde measurements and CASTOR satellite data. It is found that the major density enhancements observed during the January 10, March 26, and April 1, 1976 storm events are all preceded by ionospheric perturbations at middle latitudes. These perturbations consist of an increase in layer height followed by an increase in the ionization density. Since these are typical signatures of TADs, the present data set confirms the idea that a significant part of the upper atmosphere storm energy is transported from high to low latitudes by large-scale waves.