HR: 1340h
AN: B43B-0166    [Abstracts]
TI: Novel Instrumentation for Methane Flux Measurements
AU: * Owano, T
EM: t.owano@lgrinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue Suite 3, Mountain View, CA 94041 United States
AU: Baer, D
EM: d.baer@lgrinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue Suite 3, Mountain View, CA 94041 United States
AU: Gupta, M
EM: m.gupta@lgrinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue Suite 3, Mountain View, CA 94041 United States
AU: Ricci, K
EM: k.ricci@LGRinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue Suite 3, Mountain View, CA 94041 United States
AU: O'Keefe, A
EM: a.okeefe@LGRinc.com
AF: Los Gatos Research, 67 East Evelyn Avenue Suite 3, Mountain View, CA 94041 United States
AB: We describe the development and testing of a new compact, rugged and inexpensive instrument for measurements of methane flux in ambient air. The instrument is based on a new technology called Off-Axis Integrated Cavity Output Spectroscopy (Off-Axis ICOS). This novel instrument measures methane with high sensitivity, accuracy (<2 ppbv at 1 Hz), and specificity in real time (no cross interferences). The instrument combines inexpensive, robust telecommunications-grade room-temperature diode laser operating at 1.65 microns with Off-Axis ICOS to yield an instrument capable of continuously recording data in the field with high precision (better than 0.2% uncertainty at a 10-Hz rate). We will discuss the measurement strategy in detail and present recent results demonstrating real-time measurements without the need for any user intervention. Ongoing efforts to demonstrate the instrument's capabilities to record measurements with high precision and accuracy without calibration over extended periods as well as testing of the instrument at field sites in the AmeriFlux and FLUXNET networks, and NOAA/CMDL will also be discussed. By significantly increasing the accuracy and precision of methane flux measurements, the Off-Axis ICOS instrument will enhance local, regional and global studies of global warming and facilitate controlled multi-year studies and comparisons between field sites. These studies, which could involve using the instruments aboard airplanes to enable coverage over large distances and to correlate with satellite images, will help track and quantify the global carbon cycle on small and large spatial scales, and enable atmospheric chemists to generate more reliable models of climate change and determine environmental impact.
UR: http://www.LGRinc.com
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0322 Constituent sources and sinks
DE: 0330 Geochemical cycles
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
DE: 0394 Instruments and techniques
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting