A new airborne laser-induced fluorescence instrument for in situ detection of formaldehyde throughout the troposphere and lower stratosphere

M. Cazorla, G. M. Wolfe, S. A. Bailey, A. K. Swanson, H. L. Arkinson, T. F. Hanisco
2015 Atmospheric Measurement Techniques  
<p><strong>Abstract.</strong> 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 laser-induced 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
more » ... 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 <i>e</i> 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.</p>
doi:10.5194/amt-8-541-2015 fatcat:3qua4aga2vewrdpbtd7r3gkq3y