The energy balance of the nighttime thermosphere

Abstract

Energy balance considerations for the thermosphere are affected by the uncertainty of the solar EUV flux. The problem is simplified by investigating only the nighttime thermosphere. Vapor trail measurements provide wind data at the sunset and sunrise terminators and near the polar cap boundary. Temperature and density profiles were obtained from incoherent scatter and Ogo 6 measurements. Based on the available data the energy losses are estimated to be 8 × 1010 W due to downward conduction at 120 km and 3 × 1010 W due to infrared radiation. The energy carried by the measured winds from the polar cap is found to be 4.6 × 1010 W and that transported across the mid‐ and low‐latitude terminators, 7.6 to 11 × 1010 W. The greatest uncertainty in this analysis was in the estimates of the differences in the densities and temperatures in the lower thermosphere at the dawn and dusk terminators. Because of the large rotational velocity of the earth, small differences in these parameters correspond to large amounts of energy transported to the night hemisphere.

A new global average model of the coupled thermosphere and ionosphere

“…At low altitudes, however, the thermosphere is optically thick to 63 μm. A parameterization by Glenar et al [1978] is used to approximate the necessary correction, giving nearly the same results as full radiative transfer calculations based on the algorithms of Craig and Gille [1969] and Kockarts and Peetermans [1970].…”

Latitudinal structure and extension of the polar atmospheric disturbance

“…The timing of the additional energy influx is such that it should induce a strong semidiurnal variation. A more detailed discussion of these energy balance considerations is given, for example, in the work of Straus et al [1975], Nisbet and Glenar (1977), Glenar et al [1978], and Richmond [1979].…”

Thermal escape of carbon from the early Martian atmosphere

“…In order to apply the model to a CO 2 ‐dominated upper atmosphere, electron impact cross sections [ Sawada et al , 1972] for both CO 2 and CO were added to the GLOW model, and atomic carbon chemistry reactions from Fox and Sung [2001] were included. The model includes radiative cooling from the CO 2 15‐ μ m band [ Gordiets et al , 1982], the NO 5.7‐ μ m band [ Kockarts , 1980], and the atomic oxygen fine structure 63‐ μ m band [ Glenar et al , 1978]. In addition, we include CO 4.7‐ μ m band cooling by employing the Einstein A‐coefficient expressions in Chin and Weaver [ Chin and Weaver , 1984], using an average value of 16.3 s −1 for all ro‐vibrational transitions between v = 1 and v = 0 states.…”