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Abstract: A diode laser spectrometer was used in the Groupe de Spectrométrie Moléculaire et Atmosphérique of Reims (France) to study CO2 line intensities, self-broadening coefficients and air-pressure-broadening coefficients near 2.063μm. The spectral region ranging from 4843 to 4848cm−1, which is suitable for the measurement of atmospheric carbon dioxide (CO2) mixing ratios was studied using a new generation-commercial diode laser from Nanoplus. Three lines of the (20°1)III←(000) band of CO2 have been studied. The results of intensity measurements and self-broadening coefficients are compared with previous determinations and available databases. Furthermore, the air-broadening coefficients for these transitions are also reported and analyzed. Finally, these new parameters are used for the measurement of atmospheric CO2 mixing ratio with the 2μm heterodyne differential absorption Lidar from the Laboratoire de Météorologie Dynamique at Palaiseau (France). These new parameters demonstrate a dramatic improvement of the retrieved atmospheric CO2 concentrations. [Copyright &y& Elsevier]

Abstract: Atmospheric carbon dioxide (CO2) is one of the main contributors to the greenhouse effect. A global monitoring of CO2 from space is foreseen as a key issue to quantify its sources and sinks at a regional scale and to better predict future levels of CO2 and their effect on climate change. Differential Absorption Lidar (DiAL) is a promising and novel spectroscopic technique for remote sensing CO2 spatial and temporal concentration distribution with a high level of accuracy. However, a precise knowledge of spectroscopic parameters of CO2 molecular transitions and their dependence with temperature and pressure is required for reducing the uncertainty on DiAl measurements. Hence, to support remote sensing of carbon dioxide in the troposphere, we report on the accurate determination of air pressure-induced shift coefficients for eight absorption lines belonging to the R branch of (2001)III←(0000)I band of CO2 at 2.05μm. Purposely, a high-resolution tunable diode laser absorption spectrometer (TDLAS) coupled to a cryogenically cooled optical cell was implemented. From these measurements, we have further determined the temperature-dependencies of the air pressure-induced shift coefficients. [Copyright &y& Elsevier]

Abstract: The self-broadening coefficients of acetylene at room temperature have been measured for 10 lines in the P branch of the bands of 12C2H2 and 13C12CH2 near 1.533μm, using a high resolution tunable diode laser spectrometer developed for the Martian space mission PHOBOS-Grunt. The collisional widths are obtained by fitting each recorded line with the Voigt profile as well as the Rautian profile accounting for the collisional Dicke narrowing effect. The standard Voigt model provides slightly smaller broadening coefficients than the Rautian model. Our data are thoroughly compared to the main atmospheric molecule database HITRAN and previous values in various bands of acetylene. Moreover, it is worth noting that a large number of new transitions not listed in the latest HITRAN08 were measured and identified for the first time. [ABSTRACT FROM AUTHOR]

Abstract: A quantum cascade laser spectrometer was used in the Groupe de Spectrométrie Moléculaire et Atmosphérique of Reims (France) to precisely study nitrous oxide (N2O) line parameters near 7.9μm. The spectral region ranging from 1275 to 1280cm–1, which is suitable for the in situ measurement of N2O in the atmosphere from balloon-borne measurements, was studied using a commercial laser from Alpes Lasers. Five lines of the ν 1 band of N2O have been studied. The results of intensity measurements, air-broadening coefficients and their variation with temperature from −58°C up to ambient temperature are compared with previous determinations and available databases. These results demonstrate that these parameters for N2O are quite well known in the literature. Parameters obtained in this work are given with a very high precision. [Copyright &y& Elsevier]