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Fast Response tunable diode laser spectroscopy for trace gas flux measurements

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dc.contributor.author Wienhold, F.G.
dc.contributor.author Fischer, H.
dc.contributor.author Harris, G.W.
dc.date.accessioned 2010-06-11T14:50:02Z
dc.date.available 2010-06-11T14:50:02Z
dc.date.issued 1996
dc.identifier.citation Infrared Physics and Technol., 37, 67-74. en
dc.identifier.uri http://hdl.handle.net/10315/4205
dc.description.abstract A fast tunable diode laser spectrometer was applied for measurements of N2O emissions from a harvested wheat field located in Sealand, Denmark. The dual-channel instrument uses two tone frequency modulation and signal detection at 11 MHz in conjunction with rapid (1 ms) scanning of the laser. A dichroic beam combiner and a mechanical chopper allow time multiplexing. The absorption signals are recorded and analysed on-line. The combination of a software, current and temperature controlled line locking scheme results in high stability of the instrument. The time response (200 ms) of the spectrometer is limited by the measurement-cell gas exchange. For eddy correlation measurements, the trace gas mixing ratio and wind data were sampled synchronously at a rate of 10 Hz using an interrupt-driven algorithm. Mean N2O flux detection limits were 6 pptv m s−, corresponding to a deposition velocity of 2 × 10−5 m s− for a half hour measurement time. In addition, concentration gradients were determined from measurements at four different inlet heights at 0.1 ppbv precision in a shared integration time of 30 min. These measurements resulted in a flux detection limit of 7 pptv m s−1 ror the boundary layer mixing conditions encountered. en
dc.language.iso en en
dc.publisher Elsevier en
dc.title Fast Response tunable diode laser spectroscopy for trace gas flux measurements en
dc.type Article en
dc.rights.journal http://www.elsevier.com/wps/find/journaldescription.cws_home/525439/description#description en

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