A. I. Semenov

Pre-dawn emission at 6300 Å and super-thermal ions from conjugate points

Abstract Analysis of the behaviour of the Doppler temperature and intensity of the red oxygen emission are presented. In winter the maximum of the Doppler temperature occurs about 1.5 h before the maximum of the intensity. A possible hypothesis to explain this phenomenon are discussed.

Estimate of seasonal changes in the intensity of the infrared atmospheric system of molecular oxygen

On the basis of measurements of the intensity of 1.58-μm emissions of the Infrared Atmospheric System of molecular oxygen (IRAO2) conducted at the Zvenigorod scientific station of the Institute of Atmospheric Physics of the Russian Academy of Sciences (φ = 55.7°N, λ = 36.8°E), seasonal variations are estimated for various solar zenith angles. Their amplitude has the maximum value at the solar zenith angles χS ∼ 105–110°. It decreases at χS ∼ 125–130° and tends to zero at χS ∼ 80–85°. The comparison of currently measured values of the 1.58-μm emission intensity of the Infrared Atmospheric System of molecular oxygen with published data on the intensity of this emission obtained in 1961–1966 reveals their decrease over approximately 50 years. This fact is in good agreement with similar behavior of the emission intensity of atomic oxygen (557.7 nm) over the period considered.

Empirical Model of Variations in the Helium 1083 nm Emission. 1. Intensity

The model of variations in the orthohelium 1083 nm emission intensity has been constructed based on the measurements at different stations. The analytical approximations of the nighttime intensity variations depending on the phase age of the Moon, season, solar activity during the 11-year cycle, and geomagnetic disturbances are presented.

Emission of the upper atmosphere is a sensitive indicator of solar — terrestrial processes: Summary of results over a period of 60 years

The paper presents the main results obtained over the last 60 years in the main directions of studies on emissions in the upper atmosphere during nighttime, twilight and daytime hours at heights of above 80 km and discusses their connection to other regions in the atmosphere and solar processes.

Empirical model of variations in 656.3-nm hydrogen emission

Based on the measurements of 656.3-nm emission of atomic hydrogen, we constructed a model of variations in its intensity, which describes the dependence of diurnal, lunar, seasonal, latitudinal, and long-term variations, during the 11-year cycle of solar activity, cyclic aperiodic variations, and variations after geomagnetic disturbances.

Empirical model of variations in the helium 1083 nm emission. 2. Temperature

Based on the measurements of the ortho helium 1083 nm emission intensity during twilights and on the calculation of its variations depending on the solar zenith angle, the method for determining the atmospheric temperature at heights of 300–1000 km during the nighttime period of day has been developed, taking into account the diurnal and seasonal conditions.

Detection of short-period global waves from nightglow observations

Atmospheric temperature oscillations at similar frequencies have been detected in the spectra of variations in the rotational temperatures of the OH and O2 nighttime emissions, simultaneously observed at two spaced stations in the range of periods ∼1–3 h. These oscillations are probably caused by global waves: short-period solar tides and/or free oscillations of the atmosphere.