Closed-path Laser Hygrometer

Status

Status
Operational
(Last flown in 2006; unchanged and still operational)
Operated By
PI
Replaced By
CLH2

The University of Colorado closed-path tunable diode laser hygrometer (CLH) is based on the water vapor hygrometers designed by R. D. May (Maycomm, Inc.). CLH is coupled to a heated, forward-facing inlet that enhances particulate water by anisokinetic sampling. Ice water content (IWC) is derived from the measurement of enhanced total water, with knowledge of the instrument sampling characteristics, particle size distributions and ambient water vapor.

In contrast to the open-path systems of similar heritage, the CLH, which was designed for operation in the troposphere on commercial aircraft, has a single-pass absorption cell (27.62 cm long). The light source is a room-temperature solid-state laser that puts out 3-5 mW of radiation at 1.37 mm (7306.752 cm-1).

Instrument Type
Laser absorption
Measurements
H2O (total)
Aircraft
Gulfstream V - NSF,
WB-57 - JSC,
DC-8- AFRC
Recent Missions
SOLVE
(DC-8- AFRC)
;
PUMA
(WB-57 - JSC)
;
MACPEX
(WB-57 - JSC)
;
TC4
(WB-57 - JSC)
;
MidCiX
(WB-57 - JSC)
;
CRYSTAL FACE
(WB-57 - JSC)
Point(s) of Contact
Linnea Avallone
(POC; PI),
Darin Toohey
(PI)
Range of Measurement
In situ
Measurement Sampling Rate
0.80 Hz
Data Delivery
Real time (preliminary); 6 months (final)
Weight
16.00 kg
Size
51.00 cm (L) x 25.00 cm (W) x 15.00 cm (H)
Power:
150.00 W
Has Pressurized Canisters? Yes
Location
Right wing pod of the WB-57 during MACPEX, CRYSTAL-FACE, MidCiX, and PUMA. Special inlet on DC-8 window plate for SOLVE.
Website
http://lasp.colorado.edu/~avallone/totalwater.html
Publications

 

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