A new airborne laser-induced fluorescence instrument for in situ detection of...

Cazorla, M., G. M. Wolfe, S. A. Bailey, A. Swanson, H. Arkinson, and T. F. Hanisco (2015), A new airborne laser-induced fluorescence instrument for in situ detection of formaldehyde throughout the troposphere and lower stratosphere, Atmos. Meas. Tech., 8, 541-552, doi:10.5194/amt-8-541-2015.

The NASA In Situ Airborne Formaldehyde (ISAF) instrument is a high-performance laser-based detector for gas-phase formaldehyde (HCHO). ISAF uses rotational-state specific laser excitation at 353 nm for laserinduced fluorescence (LIF) detection of HCHO. A number of features make ISAF ideal for airborne deployment, including (1) a compact, low-maintenance fiber laser, (2) a single-pass design for stable signal response, (3) a straightforward inlet design, and (4) a stand-alone data acquisition system. A full description of the instrument design is given, along with detailed performance characteristics. The accuracy of reported mixing ratios is ±10 % based on calibration against IR and UV absorption of a primary HCHO standard. Precision at 1 Hz is typically better than 20 % above 100 pptv, with uncertainty in the signal background contributing most to variability at low mixing ratios. The 1 Hz detection limit for a signal / noise ratio of 2 is 36 pptv for 10 mW of laser power, and the e fold time response at typical sample flow rates is 0.19 s. ISAF has already flown on several field missions and platforms with excellent results.

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Upper Atmosphere Research Program (UARP)