Methane and Carbon Dioxide Eddy-Covariance Flux Monitor

Methane (CH4), water vapor (H2O), and carbon dioxide (CO2) are collectively responsible for the majority of the Earth¿s greenhouse effect. Robust instrumentation that can measure these gases with both high accuracy and high precision would reduce the uncertainty in the determination of terrestrial sources and sinks of these dominant greenhouse gases. Such knowledge is needed to improve predictive models that lead to a better understanding of the human contribution to global warming. This project will build a CO2/ CH4 flux monitor based on the optical absorption technique, cavity ring-down spectroscopy (CRDS). Compared to other gas measurement techniques, CRDS is extremely sensitive and precise, and is well suited to provide rapid (10 Hz) and precise measurements of atmospheric CO2 and CH4. In addition, the analyzer will require far less calibration and sample preparation than currently available technology, leading to better reliability and reduced operating cost. Commercial Applications and other Benefits as described by the awardee: Government agencies around the world are already installing atmospheric monitoring stations, for example the Ameriflux network currently has 89 active stations in six countries. An improved CO2 and CH4 flux monitor deployed at these stations would provide high accuracy as well as high precision information at a data rate required for flux measurement.