UCATS
Summary: The Unmanned aircraft systems Chromatograph for Atmospheric Trace Species (UCATS) is comprised of a two channel gas chromatograph (GC) for trace gases including nitrous oxide (N2O), carbon monoxide (CO), sulfur hexafluoride (SF6), hydrogen (H2), and methane (CH4), an ultraviolet absorption photometer for ozone (O3), a dual pathlength tunable diode laser hygrometer for water vapor, and an exterior relative humidity and temperature probe. The gas chromatograph and ozone photometer of UCATS were previously operated on the NOAA Unmanned Aircraft Systems (UAS) demonstration using Altair in April-May and November 2005 (see http://uas.noaa.gov/altair/payload.html#ucats). One of the goals for the NASA Fire Mission is to observe emissions of trace gases that are chemically and climatically important in plumes from the forest fires.
More Details: One channel of the GC will measure atmospheric nitrous oxide and sulfur hexafluoride once every 70 seconds. The second channel of the GC will measure atmospheric hydrogen, methane, and carbon monoxide once every 140 seconds. Tropospheric ozone (0-200 ppb) or stratospheric ozone measurements (>200 ppb -10 ppm) are measured once every 10 seconds using a more precise 2B, Inc ozone photometer than that operated on the NOAA UAS Demo. The NOAA/UAV laser hygrometer (built by Maycomm Instruments, LLC) is designed to provide measurements of water vapor from an aircraft platform using near-infrared (1370 nm) laser absorption spectroscopy by second harmonic detection. It utilizes a fiber-coupled near-infrared diode laser split into two separate optical absorption paths within a single sample cell volume. A “short” optical path (13.4 cm) provides tropospheric measurements, and a “long” optical path (389 cm) provides stratospheric measurements from approximately 1000 ppmv down to approximately 1 ppmv. Ambient air temperature (-70 C to 40 C) to 0.1 C accuracy and relative humidity measurements (0-100%) are reported once every second using a Vaisala probe.
Goals: The scientific goals for UCATS during the NASA Fire Mission are the following:
- Test new temperature/relative humidity probe, new tunable diode laser spectrometer for water vapor, new H2, CH4, CO GC-ECD channel, and an upgraded ozone photometer.
- If plane operates in forest fire plumes, UCATS will measure biomass burning trace gases, including H2O, CO, H2, CH4, N2O, and the secondary product, O3.
- Observe troposphere-stratosphere exchange events if present.
- Observe emissions of man-made tropospheric pollution from cities (SF6, CO, and O3).
- Validate instruments on the NASA Aura satellite for H2O, O3, N2O, CH4, and N2O.
- Continue interagency cooperation with NASA and US Forest Service started with the 2005 NOAA UAS demonstration.
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