CAFE: a new, improved nonresonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde

St. Clair, Jason M.; Swanson, Andrew K.; Bailey, Steven A.; Hanisco, Thomas F.

NASA Compact Airborne Formaldehyde Experiment (CAFE) is a nonresonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde (HCHO). The instrument is described here with highlighted improvements from the predecessor instrument, COmpact Formaldehyde FluorescencE Experiment (COFFEE). CAFE uses a 480 mW, 80 kHz laser at 355 nm to excite HCHO and detects the resulting fluorescence in the 420–550 nm range. The fluorescence is acquired at 5 ns resolution for 500 ns and the unique time profile of the HCHO fluorescence provides measurement selectivity. CAFE achieves a 1σ precision of 160 pptv (1 s) and 90 pptv (10 s) for [HCHO] = 0 pptv. The accuracy of CAFE, using its curve-fitting data processing, is estimated as ±20 % of [HCHO] + 100 pptv. CAFE has successfully flown on multiple aircraft platforms and is particularly well-suited to high-altitude research aircraft or small air quality research aircraft where high sensitivity is required but operator interaction and instrument payload is limited.

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St. Clair, Jason M. / Swanson, Andrew K. / Bailey, Steven A. / et al: CAFE: a new, improved nonresonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde. 2019. Copernicus Publications.

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Rechteinhaber: Jason M. St. Clair et al.

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