Portable, low power soil gas analyzer

There is a need for soil gas analyzers to characterize subsurface biogeochemical processes by measuring simultaneously multiple gases that are signatures for specific processes. Instruments should be significantly more portable and require less power than what is currently available. The analyzers need to be suitable for field work and laboratory studies. Rugged, compact, low power, and reasonably priced instruments will be developed for simultaneous measurements of at least six key gases (carbon dioxide, methane, water vapor, oxygen, nitrogen, and nitrous oxide). Commercial instruments will be fully automated and operate without requiring consumable supplies. The Phase I project will evaluate several approaches to gas analysis to determine which best meet the needs of expected end users. Evaluations will emphasize long term stability. Carbon dioxide, methane, water vapor, oxygen, and nitrogen will be measured simultaneously using one optical method. Nitrous oxide will be measured using a different optical technique. Commercial Applications: Commercial gas analyzers will be suitable for field studies including long-term continuous monitoring of nitrogen-cycle and carbon-cycle processes. Specific end user applications include characterizing biologic respiration, CH4 oxidation, dissolution of CO2, reaction with soil carbonate, and atmospheric mixing. Instruments will be easily transported for field work, fully automated, self-calibrating, and will operate at low power. Direct measurement of multiple soil gases including nitrogen now requires multiple analyzers.