科學(xué)家應(yīng)用LGR氨氣分析儀快速原位機(jī)載測量空氣中氨氣的含量
Fast in situ Airborne Measurement of Ammonia
Using a Mid-Infrared Off-Axis ICOS Spectrometer
科學(xué)家應(yīng)用LGR氨氣分析儀快速原位機(jī)載測量空氣中氨氣的含量，這可以幫助我們更好的分析大氣的成分和氣溶膠的組成，具有深遠(yuǎn)的意義。
J. Brian Leen,?,* Xiao-Ying Yu,?,* Manish Gupta,? Douglas S. Baer,? John M. Hubbe,? Celine D.Kluzek, ? Jason M. Tomlinson,? and Mike R. Hubbell II?
?Los Gatos Research Inc., 67 E. Evelyn Ave, Suite 3, Mountain View, CA 94041
?Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352
ABSTRACT:
A new ammonia (NH3) analyzer was developed based on off-axis integrated cavity output?spectroscopy. Its feasibility was demonstrated by making tropospheric measurements in flights?aboard the Department of Energy Gulfstream-1 aircraft. The ammonia analyzer consists of an?optical cell, quantum-cascade laser, gas sampling system, control and data acquisition?electronics, and analysis software. The NH3 mixing ratio is determined from high-resolution?absorption spectra obtained by tuning the laser wavelength over the NH3 fundamental vibration?band near 9.67 μm. Excellent linearity is obtained over a wide dynamic range (0 - 101 ppbv) with?a response rate (1/e) of 2 Hz and a precision of ±90 pptv (1σ in 1 s). Two research flights were?conducted over the Yakima Valley in Washington State. In the first flight, the ammonia analyzer?was used to identify signatures of livestock from local dairy farms with high vertical and spatial?resolution under low wind and calm atmospheric conditions. In the second flight, the analyzer?captured livestock emission signals under windy conditions. Our results demonstrate that this?new ammonia spectrometer is capable of providing fast, precise, and accurate in situ?observations of ammonia aboard airborne platforms to advance our understanding of?atmospheric compositions and aerosol formation.