科学家应用LGR氨气分析仪快速原位机载测量空气中氨气的含量
Fast in situ Airborne Measurement of Ammonia
Using a Mid-Infrared Off-Axis ICOS Spectrometer
科学家应用LGR氨气分析仪快速原位机载测量空气中氨气的含量，这可以帮助我们更好的分析大气的成分和气溶胶的组成，具有深远的意义。
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.