Eddy covariance imaging of diffuse volcanic CO2 emissions at Mammoth Mountain, CA, USA

Use of eddy covariance (EC) techniques to map the spatial distribution of diffuse volcanic CO 2 fluxes and quantify CO 2 emission rate was tested at the Horseshoe Lake tree-kill area on Mammoth Mountain, California, USA. EC measurements of CO 2 flux were made during September–October 2010 and ranged from 85 to 1,766 g m −2 day −1 . Comparative maps of soil CO 2 flux were simulated and CO 2 emission rates estimated from three accumulation chamber (AC) CO 2 flux surveys. Least-squares inversion of measured eddy covariance CO 2 fluxes and corresponding modeled source weight functions recovered 58–77% of the CO 2 emission rates estimated based on simulated AC soil CO 2 fluxes. Spatial distributions of modeled surface CO 2 fluxes based on EC and AC observations showed moderate to good correspondence ( R 2 = 0.36 to 0.70). Results provide a framework for automated monitoring of volcanic CO 2 emissions over relatively large areas.