Refined laser heterodyne spectroscopy technology for precise greenhouse gas monitoring

Carbon dioxide and methane are key greenhouse gases emitted by human activities, accounting for ~75% and ~18% of total greenhouse gases emissions at the global scale. However, current knowledge about the sources and sinks of both gases is still insufficient for reliable climate predictions. Space-based observations (such as GOSAT, OCO-2 and TANSAT), primary means for quantification of the sources and sinks on large scales, suffer from limited precision and sparse observational density. Whilst ground-based observations such as TCCON, equipped with high spectral resolution Fourier transform spectrometer (FTS, Bruker, IFS125HR), provide column-averaged abundances with high precision and accuracy, however the shortfalls (such as large dimensions and high cost of maintenance) limit further expansion of the observing network. Over the last decade, COCCON, which equipped with middle spectral resolution portable FTS (Bruker, EM27/SUN), has proven to be a promising complement to the ground-based observations. With the objective to develop a portable instrument maintained with high spectral resolution, a refined laser heterodyne radiometer (LHR) for precise remote sensing of greenhouse gases will be presented.