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COmpact Formaldehyde FluorescencE Experiment

The NASA GSFC COmpact Formaldehyde FluorescencE Experiment (COFFEE) instrument measures formaldehyde (CH2O) using a nonresonant laser induced fluorescence (LIF) technique.  Originally designed to fly in the unpressurized pod of the Alpha Jet, COFFEE is capable of operation on both pressurized and unpressurized (high-altitude) aircraft.  COFFEE possesses the high sensitivity, fast time response, and dynamic range needed to observe CH2O throughout the troposphere and lower stratosphere.

Formaldehyde is produced via the oxidation of hydrocarbons, notably methane (a ubiquitous greenhouse gas) and isoprene (the primary hydrocarbon emitted by vegetation). Observations of CH2O can thus provide information on many atmospheric processes, including:
 - Convective transport of air from the surface to the upper troposphere
 - Emissions of reactive hydrocarbons from cities, forests, and fires
 - Atmospheric oxidizing capacity, which relates to formation of ozone and destruction of methane
In situ observations of CH2O are also crucial for validating retrievals from satellite instruments, such as OMI, TROPOMI, and TEMPO.

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COFFEE instrument in shipping crate

A new non-resonant laser-induced fluorescence instrument for the airborne in situ measurement of formaldehyde

Photochemical model evaluation of 2013 California wild fire air quality impacts using surface, aircraft, and satellite data

Baker, K. R., et al. (2018), Photochemical model evaluation of 2013 California wild fire air quality impacts using surface, aircraft, and satellite data, Science of the Total Environment, 637–638, 1137-1149, doi:10.1016/j.scitotenv.2018.05.048.

AJAX - Alpha Jet 01/30/18 Science Report

AJAX Flight 217 (2018 January 30) - Two Wing Pods
 
Aim: To collect two sequential over-land vertical profiles of GHG, HCHO, and MMS from FL 270/280 to lowest possible altitude, for comparison with TROPOMI instrument on Sentinel 5P satellite.
 
First Target centerpoint:    39° 6' 00" N,  122° 21' 18"  W ,
                                          elev. 920 ft with local terrain to 1500 ft
Second Target centerpoint:   39° 33' 00" N, 121° 52' 00" W,            elev. ~100 ft

ARC Picarro

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NOAA Picarro

The Picarro G2401m is a commerical instrument that measures CO2, CH4, CO, and H2O. The analyzer is based on Wavelength-Scanned Cavity Ring Down Spectroscopy (WS-CRDS), a time-based measurement utilizing a near-infrared laser to measure a spectral signature of the molecule. Gas is circulated in an optical measurement cavity with an effective path length of up to 20 kilometers. A patented, high-precision wavelength monitor makes certain that only the spectral feature of interest is being monitored, greatly reducing the analyzer’s sensitivity to interfering gas species, and enabling ultra-trace gas concentration measurements even if there are other gases present. As a result, the analyzer maintains high linearity, precision, and accuracy over changing environmental conditions with minimal calibration required.

The measurement software of the NOAA Picarro has been modified to have a shorter measurement interval (~1.2 seconds instead of ~2.4 seconds) by reducing the number of scans of the CO spectroscopic peak and therefore yielding a less-precise CO measurement (1σ on 1-2 second measurements is ~9 ppb instead of ~4 ppb). The instrument was also modified to have a lower cell pressure set point (80 torr instead of 140 torr) to allow it to operate across the full pressure altitude range of the DC8 without requiring upstream pressurization of the sample stream.

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AJAX Team mounting pod onto Alpha Jet

AJAX Team mounting pod onto Alpha Jet

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