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Daily radiosonde observations between 2003 and 2013 from Halley research station, Antarctica (75°S, 26°W), are used to determine climatologies of gravity wave properties in the lower stratosphere (between 15 km and 22 km altitude). Individual waves are extracted from the radiosonde profile using wavelet analysis and separated into upward and downward propagating waves. An increase in the percentage of downward propagating waves (~30% of the waves) is seen during the winter months. For the upward and downward propagating waves, their horizontal and vertical wavelength, intrinsic frequency, energy density, pseudomomentum flux, and direction of propagation are determined. The upward propagating wavefield is found to be dominated by waves with short vertical wavelength (~1 km) and low intrinsic frequency (ω ~ f). The downward propagating wavefield is composed of a wider distribution of vertical wavelength waves and has a larger proportion of higher‐frequency waves present. The upward propagating waves show an increase in total energy density in autumn and spring; the larger increase occurs during spring (up to 1.7 J kg−1in September). The downward propagating waves increase in total energy density occurs during wintertime (up to 0.7 J kg−1in June). During winter the contributions of the upward and downward propagating waves to the total energy density and pseudomomentum flux are almost equal. This paper details the first study of individual gravity wave properties combined into upward and downward propagating wave climatologies in the lower stratosphere above Halley. Upward propagating gravity wavefield in lower stratosphere dominated by low‐frequency, short vertical wavelength wavesDownward propagating wavefield in lower stratosphere contains waves with a wider range of wavelengths and many at higher frequenciesIn wintertime the downward propagating waves contribute as much as upward propagating waves to the energy density and momentum fluxes

Previously proposed, semi-classical quantization conditions are further examined and then used to calculate low-lying vibrational energy levels of SO2 and H2O. Results are compared with variational quantum-mechanical results, using various realistic analytic potentials.

The reaction path hamiltonian of Miller, Handy and Adams was used to investigate the isomerization CH3O → CH2OH, which is of interest in atmospheric chemistry. The equilibrium configurations, transition state and reaction path were calculated using the restricted Hartree-Fock (RHF) and complete active space self consistent field (CASSCF) methods, with STO-3G and double zeta basis sets.The microcanonical and temperature dependent rate constants were calculated with and without tunnelling using RHF and CASSCF with an STO-3G basis. It was found that the tunnelling correction is important, but that at temperatures below 1000 K the reaction does not proceed significantly.

Satellite observations show that there is a wintertime hotspot of gravity wave activity, located mainly over the ocean, around 60°S in the stratosphere. However, the sources of the gravity waves making up this hotspot are varied and complex and remain unclear. Here we use radiosonde observations from 11 Antarctic stations and selected small islands close to 60°S to examine the horizontal directional pseudo‐momentum flux and energy density distributions of upward propagating gravity waves in the lower stratosphere. This paper shows, for the first time, that short vertical wavelength gravity waves in the lower stratosphere clearly propagate meridionally toward 60°S during the winter months. This result supports previous studies that show that this belt of gravity wave activity over the ocean is contributed to by wave sources outside 60°S. Atmospheric gravity waves are buoyancy waves, where the restoring force is gravity, which can have horizontal wavelengths from a few tens to hundreds of kilometers. They can be generated by a variety of sources including wind flow over mountains and storms. Over the Drake Passage and out to the east around 60°S, a large hotspot of gravity waves has been observed in the wintertime stratosphere using satellite observations. The sources for this gravity wave hotspot are unclear as it mainly located over the open ocean. In this paper radiosonde observations are used to examine, for the first time, the directional variation in short vertical wavelength gravity waves close to 60°S in the lower stratosphere. It is found that during the winter months there is a meridional convergence of gravity waves toward 60°S, implying that the gravity wave sources of the hotspot are in fact be outside this region. This paper provides evidence of a winter time convergence of gravity waves and their momentum flux toward 60°SThis is the first time this has been observed for short vertical wavelength waves in the lower stratosphere

The fundamental differences in bonding between boron hydrides and hydrocarbons are illustrated by energetic results from MO calculations.