Atmospheric Sciences Division Seminar

We report on the development, application and performance characterization of novel gas analyzers based on cavity-enhanced laser absorption spectroscopy. These relatively novel analyzers require only about 100 watts of power and do not need liquid nitrogen. The Fast Greenhouse Gas Analyzer (FGGA) provides simultaneous measurements of methane, carbon dioxide and water vapor in ambient air in the field and on aircraft for applications that require high data rates (eddy correlation flux), wide dynamic range (e.g., chamber flux and other applications with concentrations that are 100 times typical ambient levels or higher), and highest accuracy (atmospheric monitoring stations). The FGGA provides continuous measurements at data rates up to 20 Hz and with replicate precision of 1 ppbv for methane (1 second measurement time), 0.2 ppmv for carbon dioxide (1 second measurement time) and 100 ppmv for water vapor (1 second measurement time). The Carbon Dioxide Isotope Analyzer provides simultaneous measurements of carbon dioxide concentration and δ13C (0.25 per mil in 60 seconds) in ambient air in measurement times as short as 1 second. The Liquid Water Isotope Analyzer reports simultaneous measurements of δ18O and δ2H in liquid water samples with a precision better than many Isotope Ratio Mass Spectrometers and with a throughput of over 120 samples per day. Along with a brief description of the operational principles of these instruments, several examples of field deployments will be presented.