Vertical cavity laser hygrometer for the National Science Foundation Gulfstream-V aircraft

• Published in: Journal of Geophysical Research: Atmospheres Vol. 115; no. D20; pp. 1RR - n/a
• Main Authors: Zondlo, Mark A., Paige, Mark E., Massick, Steven M., Silver, Joel A.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 27.10.2010; American Geophysical Union
• Subjects: Aircraft; Atmospheric sciences; Earth sciences; Earth, ocean, space; Exact sciences and technology; Geophysics; hygrometer; Hygrometry; laser sensor; Scientific apparatus & instruments; Stratosphere; Troposphere; Water vapor; altitude; laser methods; detection limit; foundations; concentration; pressure; Real time system; Optical system; Absorption line; instruments; corrections; water vapor; temperature; performances; stratosphere
• ISSN: 0148-0227; 2169-897X; 2156-2202; 2169-8996
• DOI: 10.1029/2010JD014445

A vertical cavity diode laser hygrometer using two absorption lines near 1854 nm has been developed for the National Science Foundation Gulfstream‐V aircraft. This instrument operates from the surface to the lower stratosphere, measuring 6 orders of magnitude in water vapor concentration. The optical system consists of an open‐path multiple‐pass cell mounted on an aerodynamic pylon. The self‐operating hygrometer reports concentration in real time at 25 Hz and uses a novel approach for fitting the data with minimal correction terms for changes in ambient pressure and temperature. The instrument intercompares with existing research grade hygrometers in the 2%–10% range. A minimum detection limit of 3.6 × 1011 molecules/cm2 or 0.08 ppmv at 15 km altitude conditions is achieved. The design rationale, operation, and flight performance of the hygrometer are described in this work.