Automating Analyzer Background Calibration for a Long-Term Flux Chamber System

The use of in-situ high precision gas analyzers for soil flux chamber measurements has dramatically improved the quality of collected data compared to manual sampling. When deployed in the field long-term, these systems can provide high resolution monitoring of both baseline and event-driven emissions. These environments pose challenges to maintaining complex instrumentation however, especially in humid or varying temperature conditions. These physical factors can accelerate calibration drift, and thus require more frequent intervention to correct this effect.

We present a methodology for automating this recalibration in-situ as applied to a Gasmet GT5000 Terra FTIR Gas Analyzer coupled with an Eosense autochamber system. Through the use of a simple hardware module, nitrogen gas based background calibrations can be scheduled alongside soil flux chamber measurements without the need for manual intervention such as changing fittings or opening tanks. This combined system allows for reference gas corrections at pre-planned intervals, or reactively in response to changes in ambient temperature or sampled water content.