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Vibration-rotation line lists for AlF, Al 35 Cl, and Al 37 Cl have been prepared in their ground electronic states (X 1 S +). Experimental rotational and ro-vibrational lines were employed to calculate a potential energy surface (PES) by direct potential fitting. The PES was used to calculate ro-vibrational energy levels. Born-Oppenheimer Breakdown corrections were included in the energy level calculations for AlCl. Ro-vibrational energy levels were calculated for the v=0 to v=11 vibrational levels and up to J max =200 for the rotational levels. Dipole moment functions covering the range of the PES turning points were calculated for AlCl and AlF by ab initio methods and used to determine line intensities. Partition functions for temperatures up to 3000 K were calculated. AlF and AlCl have been detected in circumstellar envelopes and are predicted to occur in cool stellar and sub-stellar atmospheres.

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The distributions of the four most abundant isotopologues and isotopomers (N2O, 15NNO, N15NO, and NN18O) of nitrous oxide have been measured in the Earth's stratosphere by infrared remote sensing with the Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer. These satellite observations have provided a near‐global picture of N2O isotopic fractionation. The relative abundances of the heavier species increase with altitude and with latitude in the stratosphere as the air becomes older. The heavy isotopologues are enriched by 20–30% in the upper stratosphere and even more over the poles. These observations are in general agreement with model predictions made with the Whole Atmosphere Community Climate Model (WACCM). A detailed 3‐D chemical transport model is needed to account for the global isotopic distributions of N2O and to infer sources and sinks.

Abstract. An optimal estimation-based algorithm is developed to retrieve number density of excited oxygen (O2) molecules that generate airglow emissions near 0.76 μm (A band) and 1.27 μm (1Δ band) in the upper atmosphere. Both oxygen bands are important for the remote sensing of greenhouse gases. The algorithm is applied to the limb spectra observed by the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument in both nominal (tangent heights below ~90 km) and mesosphere-lower thermosphere (MLT) modes (tangent heights spanning 50–150 km). The number densities of emitting O2 in the 1Δ band are retrieved in an altitude range of 25–100 km near daily in 2010, providing a climatology of O2 1Δ band airglow emission. This climatology will help disentangle airglow from backscattered light in nadir remote sensing of the 1Δ band. The global monthly distributions of the vertical column loading of emitting O2 in 1Δ state show mainly latitudinal dependence without other discernible geographical patterns. Temperature profiles are retrieved simultaneously from the spectral shapes of the 1Δ band airglow emission in the nominal limb mode and from both 1Δ and A band airglow emissions in the MLT mode. The temperature retrievals from both airglow bands are consistent internally and in agreement with independent observations from ACE-FTS and MIPAS with absolute mean bias near or below 5 K and root mean squared error (RMSE) near or below 10 K. The retrieved emitting O2 number density and temperature provide a unique dataset for remote sensing of greenhouse gases and constraining the chemical and physical processes in the upper atmosphere.