A global model of the neutral thermosphere in magnetic coordinates based on OGO 6 data

Abstract

Data from the OGO 6 satellite have been analyzed in magnetic latitude and magnetic local time coordinates for various seasons and magnetic activity levels. These measurements show considerable detail, particularly in the auroral regions where the energy inputs are well organized in this coordinate system. This detail is not readily observed in models based on geographic coordinates. Atomic oxygen and helium densities and a parameter related to the molecular nitrogen density were analyzed. The long‐term averages of these quantities are presented in graphical form and as analytic functions to provide models of these thermospheric parameters. The atomic oxygen and helium densities show minima at high latitudes in the postmidnight sector for nearly all seasons and magnetic activity levels. The exospheric temperature inferred from the N2 density increases toward high latitudes for all seasons and all magnetic activity levels. This inferred temperature is about 300° K higher at the summer magnetic pole than at the winter magnetic pole. This article contains supplementary material.

Morphology of thermospheric composition variations in the quiet polar thermosphere from Dynamics Explorer measurements

“…When displayed in magnetic latitude/magnetic local time coordinates, the heating is found to maximize in the early morning hours [Taeusch and Hinton, 1975;Nisbet and Glenar, 1977]. These variations have been incorporated in several empirical models [Hedin et al, 1979;Laux and yon Zahn, 1979;Stehle et al, 1982Stehle et al, , 1983Hedin, 1983] which represent, to a fair degree, the average longitudinal behavior.…”

Thermospheric circulation, temperature, and compositional structure of the southern hemisphere polar cap during October–November 1981

“…The large-scale pattern of compositional variation over the polar cap has been presented by Hedin and Reber [1972], Reber and Hedin [1974], Taeusch and Hinton [1975], and Hinton [1978]. The main compositional features at high latitudes have been incorporated into an expanded version of the mass spectrometer and incoherent scatter radar (MSIS) empirical model [Hedin et al, 1979;Hedin, 1983] and in the European Space Research Organization (ESRO 4) empirical model [Laux and yon Zahn, 1979], both of which include 1ongitude/UT effects.…”

“…The longitude/UT variations are generally present at low magnetic activity levels and increase with increased activity. Stehle et al [1982] presented a global model of the neutral temperature and composition in magnetic coordinates which shows minimum values of O at high latitudes in the postmidnight sectors for nearly all seasons and magnetic activity levels. Minimum values of O in the high-latitude postmidnight sector of the lower thermosphere have also been derived by Nisbet and Glenar [1977].…”