Seasonal dependence of the response of the low latitude thermosphere for external forcings

Abstract

Using the in situ measured neutral temperatures by the DE-2 satellite, the D st geomagnetic index which is a measure of the intensity of earth's ring current along with the MSIS model predictions, the low latitude thermosphere has been shown to have a delayed response to any energy input over polar regions with the time delay revealing a seasonal dependence. The response time has been observed to vary between 8 and 20 h from summer to winter. Interestingly, the response sensitivity of the thermosphere for any change in D st index remained nearly the same throughout the year implying other forcings to be responsible for the observed seasonal dependence. These aspects are presented and discussed.