Collection of quantitative chemical release field data

Demirgian, J.C.; Macha, Susan

doi:10.1002/(sici)1520-6521(1999)3:2<95::aid-fact4>3.0.co;2-g

Cited by 2 publications

(2 citation statements)

References 4 publications

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“…These systems have been deployed in the field at pathlengths of hundreds of meters for CH 4 emission measurements from agricultural facilities (Childers et al 2001). Although OP/FTIR instruments are commonly calibrated in the field with calibration spectra or calibration cells, these techniques do not necessarily account for drift within the entire pathintegrated sampling volume (Demirgian and Macha 1999;Bacsik et al 2005). OP/FTIR calibration approaches have not been field tested to evaluate their capabilities for maintaining long-term measurement stability, especially in open-path systems with kilometer-scale pathlengths where sampling volume conditions may be rapidly changing (Demirgian and Macha 1999;Bacsik et al 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Although OP/FTIR instruments are commonly calibrated in the field with calibration spectra or calibration cells, these techniques do not necessarily account for drift within the entire pathintegrated sampling volume (Demirgian and Macha 1999;Bacsik et al 2005). OP/FTIR calibration approaches have not been field tested to evaluate their capabilities for maintaining long-term measurement stability, especially in open-path systems with kilometer-scale pathlengths where sampling volume conditions may be rapidly changing (Demirgian and Macha 1999;Bacsik et al 2005). Tunable diode laser absorption spectroscopy (TDLAS) CH 4 sensors with near-infrared sources have also been developed for laser scanning applications to detect natural gas leakage (Gibson et al 2006;Xia et al 2008) and to measure fugitive emission fluxes (Thoma et al 2005).…”

Section: Introductionmentioning

confidence: 99%

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Long-Path Quantum Cascade Laser–Based Sensor for Methane Measurements

Michel

Miller

Sun

et al. 2016

Journal of Atmospheric and Oceanic Technology

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A long-path methane (CH 4 ) sensor was developed and field deployed using an 8-mm quantum cascade laser. The high optical power (40 mW) of the laser allowed for path-integrated measurements of ambient CH 4 at total pathlengths from 100 to 1200 m with the use of a retroreflector. Wavelength modulation spectroscopy was used to make high-precision measurements of atmospheric pressure-broadened CH 4 absorption over these long distances. An in-line reference cell with higher harmonic detection provided metrics of system stability in rapidly changing and harsh environments. The system consumed less than 100 W of power and required no consumables. The measurements intercompared favorably (typically less than 5% difference) with a commercial in situ methane sensor when accounting for the different spatiotemporal scales of the measurements. The sensor was field deployed for 2 weeks at an arctic lake to examine the robustness of the approach in harsh field environments. Shortterm precision over a 458-m pathlength was 10 ppbv at 1 Hz, equivalent to a signal from a methane enhancement above background of 5 ppmv in a 1-m length. The sensor performed well in a range of harsh environmental conditions, including snow, rain, wind, and changing temperatures. These field measurements demonstrate the capabilities of the approach for use in detecting large but highly variable emissions in arctic environments.

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