Eddy covariance measurement of CO2 flux to the atmosphere from an area of high volcanogenic emissions, Mammoth Mountain, California

Three pilot studies were performed to assess application of the eddy covari ance micrometeorological method in the measurement of carbon dioxide (CO2) flux of volcanic origin. The selected study area is one of high diffuse CO2 emission on Mammoth Mountain, CA. Because terrain and source characteristi cs make this a complex setting for this type of measurement, added consider ation was given to source area and upwind fetch. Footprint analysis suggest s that the eddy covariance measurements were representative of an upwind el liptical source area (3.8 X 10(3) m(2)) which can vary with mean wind direc tion, surface roughness, and atmospheric stability. CO2 flux averaged 8-16 mg m(-2) s(-1) (0.7-1.4 kg m(-2) day(-1)). Eddy covariance measurements of flux were compared with surface chamber measurements made in separate studi es [Geophys. Res. Lett. 25 (1998a) 1947; EOS Trans. 79 (1998) F941.] and we re found to be similar. (C) 2001 Elsevier Science B.V. All rights reserved.