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.
CAFE: a new, improved nonresonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde
St. Clair, J.M., A.K. Swanson, S.A. Bailey, and T.F. Hanisco (2019), CAFE: a new, improved nonresonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde, Atmos. Meas. Tech., 12, 4581-4590, doi:10.5194/amt-12-4581-2019.
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Tropospheric Composition Program (TCP)
Upper Atmosphere Research Program (UARP)
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