A reexamination of the O I 6300‐Å nightglow

Abstract

In an analysis of 6300‐Å nightglow measurements obtained at Arecibo on the night of April 25/26, 1976, Cogger et al. (1980) reported that model estimates exceeded the observed 6300‐Å intensity by a factor of 2. We have reanalyzed the data in light of newer laboratory and aeronomic determinations of the parameters used to calculate the 6300‐Å intensity and now obtain agreement with the measurements. The rate coefficient for the reaction O+ + O2 → O2+ + O required to fit the data is 27% smaller at 700 K than previously assumed, but is in agreement with the thermal drift tube measurements of Chen et al. (1978). A specific recombination rate of 1.2×107 cm³ s−1 (at 700 K) for production of O(¹D) from O2+ is consistent with the data. This value is somewhat smaller than the recent theoretical calculation of Guberman (1988) for recombination from O2+(υ = 0) and may imply that O2+ is not completely vibrationally relaxed in the nighttime thermosphere. The reaction N(²D) + O2 → NO + O(¹D) contributes <10% to nightglow 6300‐Å production, even for an assumed O(¹D) yield of unity. Quenching of O(¹D) by O(³P) and the larger transition probabilities suggested by Abreu et al. (1986) result in calculated 6300‐Å intensities virtually indistinguishable from those obtained using the rate coefficients of Link et al. (1981). This suggests that it will be difficult to verify O(¹D) quenching by atomic oxygen using nightglow measurements.

Tracking F-region plasma depletion bands using GPS-TEC, incoherent scatter radar, and all-sky imaging at Arecibo

“…Doing so again demonstrates the fact that the dark bands seen in the 630.0-nm emission are caused by the lack of electron concentration in the structure, rather than a localized uplift in the ionosphere. This is an important distinction, as the intensity of the 630.0-nm emission is dependent both on the concentration of the ionosphere as well as its height (Link and Cogger, 1988). Thus, without the additional information provided by the ISR and GPS, there is an ambiguity in interpreting the 630.0-nm emission.…”

Analysis of equatorial plasma bubble zonal drift velocities in the Pacific sector by imaging techniques

“…We use images taken of the 630.0-nm nightglow; this emission is due to the dissociative recombination of O + 2 (Link and Cogger, 1988) and is commonly used in studies of the nighttime ionosphere. At the typically assumed 630.0-nm emission height of 250 km, the field of view of the CNFI instrument approximately covers the geographic latitudes of 4 • to 16 • N, which map along field lines to cover apex heights of approximately 250 to 950 km, and the geographic longitudes of 196 • to 206 • E. The chief advantage of the field-aligned setup versus an all-sky imager is enhanced spatial resolution; in the all-sky configuration airglow emissions pass through multiple field lines before reaching the imager, while in the narrow-field, field-aligned configuration the look direction is nearly constrained to a single field line at the emission altitude range.…”

Climatology of thermospheric neutral winds over Oukaïmeden Observatory in Morocco

“…The instrument produces a twodimensional ring pattern on a high-quality CCD, which can be analyzed to produce an estimate of the line shape of an emission. For the case studied here, the emission of interest, selected by a narrowband interference filter in the instrument, is that produced by the dissociative recombination of O + 2 , which naturally occurs in the lower thermosphere peaking at an altitude of about 250 km (Link and Cogger, 1988). The lifetime of the associated emission process is long enough that the emitter thermalizes and, thus, the properties of the emitted photons are indicative of the local thermosphere.…”

“…Standard climatological models (IRI Bilitza et al (2014) and MSIS Picone et al (2002)) are used to provide estimates of the atmospheric constituents required to calculate the redline volume emission rate specified in Link and Cogger (1988). The peak altitude of the emitting layer is then found as a function of hour and day of year.…”