First measurements of nitrous oxide self-broadening and self-shift coefficients in the 0002-0000 band at 2.26 μm using high resolution Fourier transform spectroscopy

Abstract

Nitrous oxide (N2O) is one of the most important greenhouse gases in the terrestrial atmosphere and is routinely measured with ground-based FTIR networks like the Total Carbon Column Observing Network (TCCON). A spectral window for the TCCON retrievals is the 14N216O 0002-0000-band region from 4375 to 4445cm−1 (2.250–2.285μm). In our study, we present the first high-resolution Fourier transform spectrometer measurements of self-broadening and self-shift coefficients in the range of 53–1019hPa for the lines R0e–R40e of this band. The line parameters were determined at 296K using metrologically validated temperature, and pressure values, which were traced back to the SI-units. The averaged estimated relative uncertainties for the coverage factor of k=2 (two times the standard deviation) are 0.3% and 9.5% with a standard deviation of 0.1% and 5.3% for the self-broadening and the self-shift coefficients, respectively. Vacuum line positions, determined for the first time by taking the self-shift coefficients into account are also reported with an estimated averaged relative uncertainty of 1.1∗10−8 for k=2 and a standard deviation of 3∗10−9. A well-defined uncertainty assessment for the measured line parameters is given.