HR: 1340h
AN: A13C-0934 [Abstracts]
TI: Fast Methane Measurements Using a Novel Laser-based Gas Analyzer
AU: * Baer, D
EM: d.baer@lgrinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue, Mountain View, CA 94041
United States
AU: Gupta, M
EM: m.gupta@lgrinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue, Mountain View, CA 94041
United States
AU: Owano, T
EM: t.owano@lgrinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue, Mountain View, CA 94041
United States
AU: Provencal, R
EM: r.provencal@lgrinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue, Mountain View, CA 94041
United States
AU: Ricci, K
EM: k.ricci@lgrinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue, Mountain View, CA 94041
United States
AU: O'Keefe, A
EM: a.okeefe@lgrinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue, Mountain View, CA 94041
United States
AB:
Methane has increased significantly with human population levels. Pre-1750 ice core data indicates that pre-industrialization
levels were ~700 ppbv, while current levels are ~1745 ppbv. In current budget estimates of atmospheric CH4, major
contributors include both natural (wetlands) and anthropogenic sources (energy, landfills, ruminants, biomass burning, rice
agriculture). The strengths of these sources vary spatially and temporally. Estimates of emissions from wetlands are also
uncertain due to the extreme variability of these ecosystems. Because methane lifetime is relatively long (8.4 years),
atmospheric variations in concentration are small and accuracy in measurement is important for understanding spatial and
temporal variability.
We report on the application and independent performance characterization of a novel gas analyzer based on cavity-enhanced
laser absorption spectroscopy. The Analyzer was used for the measurements of methane in ambient air for eddy correlation flux
measurements and for chamber flux measurements. The Analyzer provided continuous measurements at data rates up to 20 Hz and
a replicate precision of better than 2 ppbv in a 1 second measurement time.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0340 Middle atmosphere: composition and chemistry
DE: 0365 Troposphere: composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005