Air fluorescence models require accurate Franck–Condon factors and Einstein coefficients for analyzing the intensities of N2, N+2, and O+2 emissions produced by electron bombardment of air, such as in the aurora, high-altitude nuclear explosions, and rocket-borne electron gun experiments. In our previous report, improved vibrational and rotational constants based on the latest available spectroscopic measurements for several excited and ionic states important in air fluorescence modeling were derived. These constants have been used in the present work to calculate band origins, Franck–Condon factors, and r-centroids for many band systems of nitrogen and oxygen. These results, together with electronic transition moments obtained from published papers or derived here from published emission data and measured upper-state lifetimes, have been used to compute Einstein coefficients by the r-centroid method. Einstein coefficients by integration of the product of the electronic transition moment function and vibrational wavefunctions have also been computed for comparison. For band systems involving ‘‘perturbed’’ electronic states, Einstein coefficients have been derived by simply normalizing published emission data to measured upper-state lifetimes. In this report, tables of band origin wave-lengths and wavenumbers, Franck–Condon factors, r-centroids, electronic transition moments, and Einstein coefficients are presented for 17 N2, N+2, and O+2 band systems. Plots of most of the electronic transition moment functions used in these calculations are also given. In addition, tables of Franck–Condon factors only are presented for 16 other band systems of nitrogen and oxygen, and tables of band wavelengths and Einstein coefficients are presented for 3 band systems having ‘‘perturbed’’ upper states.

Abstract. Nighttime measurements of the hydroxyl Meinel (4,2) rotational band have been used to infer the mesospheric temperature over Scandinavia from June to August during the years 1992-1995. While the nightly averaged temperatures show a statistically significant, quasi-16-day oscillation in the 1992 and 1994 summer data, none is observed during 1993 and 1995. When present, the period, amplitude, and temporal behavior of this oscillation agree with both model predictions and previous wind measurements of the (1,3) Rossby normal mode in the summer mesosphere. Thus this temperature oscillation appears to correspond to the thermal signature of the 16-day Rossby mode. Its appearance in the summer mesosphere is shown to occur when the oscillating zonal flows in the upper stratosphere near the equator are in an eastward phase, while it appears to be blocked during the westward phases. This correspondence of the 16-day wave in the summer mesosphere with the eastward equatorial wind would favor the explanation that it is generated in the winter hemisphere and propagates vertically and toward the summer pole following the westerly mean winds.

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We present a study of horizontal winds in the mesosphere and lower thermosphere (MLT) during the boreal winters of 2009-2010 and 2012-2013 produced with a new high-altitude numerical weather prediction (NWP) system. This system is based on a modified version of the Navy Global Environmental Model (NAVGEM) with an extended vertical domain up to ∼116 km altitude coupled with a hybrid four-dimensional variational (4DVAR) data assimilation system that assimilates both standard operational meteorological observations in the troposphere and satellite-based observations of temperature, ozone and water vapor in the stratosphere and mesosphere.

[1] We present an observational study of stratospheric gravity wave spectra and seasonal variations of potential energy density at the South Pole (90°S) and Rothera (67.5°S, 68.0°W), Antarctica. The gravity wave spectra are derived from the atmospheric relative density perturbation in the altitude range of 30-45 km measured by an iron Boltzmann lidar. The ground-relative wave characteristics obtained at each location are comparable, with an annual mean vertical wavelength of $4.1 km, vertical phase speed of $0.7 m s À1 , and period of $104 min. Approximately 44% of the observed waves show an upward phase progression while the rest display a downward phase progression in ground-based reference for both locations. Gravity wave potential energy density (GW-E P ) at Rothera is $4 times higher than the South Pole in winter but is comparable in summer. Clear seasonal variations of GW-E P are observed at Rothera with the winter average being 6 times larger than that of summer. The seasonal variations of GW-E P at the South Pole are significantly smaller than those at Rothera. The absence of seasonal variations in wave sources and critical level filtering at the South Pole is likely to be responsible for the nearly constant GW-E P . The minimum critical level filtering in winter at Rothera is likely to be a main cause for the winter enhanced GW-E P , as this would allow more orography-generated waves to reach the 30 to 45 km range. The stratospheric jet streams may also contribute to the winter enhancement at Rothera.