Miniature autonomous LHR for CO2 column measurements

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Globally rising and accelerating levels of CO2 in the atmosphere, most likely due to human activity and anthropogenic emissions , are believed to be the main driver of climate change . Within the global carbon biogeochemical cycle, the regional quantification of terrestrial (and to a lesser extent, oceanic) sources, sinks and feedbacks remains uncertain, particularly in the tropics . Likewise, geographical patterns of CO2 emissions from fossil sources are needed to improve upon the regional land flux estimates . Reducing uncertainties on the carbon cycle quantification is currently one of the most challenging tasks within climate research. Therefore improved instrumentation to be part of a carbon observing system is urgently needed, either to produce new dataset beyond what commercial systems are currently capable of, or to participate in the validation and constraining of flux estimation algorithms along the next generation of space-based remote sounders.We propose the demonstration of an instrument concept anticipated to enable for the first time the deployment of dense, autonomous, ground-based sounder networks for atmospheric CO2 profiling and column measurements. The concept of ultra-miniaturized thermal infrared laser heterodyne spectro-radiometer (TIR-LHR) offers significant advantages: high column measurement precision (<0.5% in 90s), high temporal resolution (~1 measurement/minute), unprecedented compact and deployable package ultimately suitable to operate autonomously as part of large networks, and moderate cost of purchase and maintenance. We believe the benefits of the proposed technology enable a significant qualitative step in greenhouse gas (GHG) measurement and associated scientific investigations. The instrument concept combines the benefits of TIR-LHR, and those of the latest miniaturization advances in laser based systems we have developed. Even though intrinsically flexible, the demonstrator will target CO2 (and H2O and SF6) as one of the most important GHG whose fluxes needs accurate characterization and monitoring.