Harvard Lyman-α Photofragment Fluorescence Hygrometer

Status

Status
Operational
Operated By
PI

The Harvard Water Vapor (HWV) instrument combines two independent measurement methods for the simultaneous in situ detection of ambient water vapor mixing ratios in a single duct. This dual axis instrument combines the heritage of the Harvard Lyman-α photo-fragment fluorescence instrument (LyA) with the newly designed tunable diode laser direct absorption instrument (HHH). The Lyman-α detection axis functions as a benchmark measurement, and provides a requisite link to the long measurement history of Harvard Lyman-α aboard NASA’s WB-57 and ER-2 aircraft [Weinstock et al., 1994; Hintsa et al., 1999; Weinstock et al., 2009]. The inclusion of HHH provides a second high precision measurement that is more robust than LyA to changes in its measurement sensitivity [Smith et al., in preparation]. The simultaneous utilization of radically different measurement techniques facilitates the identification, diagnosis, and constraint of systematic errors both in the laboratory and in flight. As such, it constitutes a significant step toward resolving the controversy surrounding water vapor measurements in the upper troposphere and lower stratosphere.

Instrument Type
Measurements
Recent Missions
(ER-2 - AFRC)
;
(ER-2 - AFRC)
;
(ER-2 - AFRC)
;
(WB-57 - JSC)
;
(WB-57 - JSC)
;
(WB-57 - JSC)
Point(s) of Contact
(Prev PI),
(POC; PI),
Range of Measurement
In situ
Measurement Sampling Rate
1.00 Hz
Weight
63.50 kg
Power:
1000.00 W
Location
The instrument package is designed to mount in a spearpod forebody for use with NASA’s ER-2 or WB-57 aircraft.

 

Disclaimer: This material is being kept online for historical purposes. Though accurate at the time of publication, it is no longer being updated. The page may contain broken links or outdated information, and parts may not function in current web browsers. Visit https://espo.nasa.gov for information about our current projects.