Wind and temperature effects on thermosphere mass density response to the November 2004 geomagnetic storm

A unique conjunction of the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) and the Challenging Minisatellite Payload (CHAMP) satellites provided simultaneous columnar neutral composition, ΣO/N 2 , and thermosphere density observations, enabling a novel study of thermospheric response to the 7–9 November 2004 geomagnetic storm. Both ΣO/N 2 and mass density showed profound response to this severe geomagnetic storm, but their latitudinal and temporal structures differed markedly.

In particular, high-latitude depletion and low-latitude enhancement in ΣO/N 2 were observed throughout the storm period, especially during the main phase. In contrast, neutral density at 400 km altitude increased from pole to pole shortly after the storm, with strongest enhancement of order 200%–400% during the main phase. Comparisons of observed thermosphere response with simulations from the National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) were carried out to interpret the observed contrasting characteristics of thermosphere composition and mass density in response to this geomagnetic storm.