Closed-path Laser Hygrometer 2

Status

Status
Operational
(Maintained in good working order; operates autonomously and can be monitored in real time from MTS)
Operated By
PI
Replaces
Closed-path Laser Hygrometer

The University of Colorado Closed-path Laser Hygrometer, version 2 (CLH2) is an infrared absorption instrument designed to measure so-called “total water”, the sum of water vapor and particulate water. It is a second-generation sensor that derives from the original CLH and was developed for the NSF DC3 campaign in 2011 as an alternative to the NCAR CVI for measurements of cloudwater contents. It has flown on the NASA DC-8 and the NSF/NCAR G-V and C-130. The most recent campaign was NSF SOCRATES in 2018. CLH-2 uses a fiber-coupled tunable diode laser at 1.37 μm to measure by absorption the water vapor resulting from the evaporation of cloud particles. The spectrometer will be housed in a modified PMS canister and coupled to a heated forward-facing inlet. Sampling of particles is deliberately sub-isokinetic, which results in enhancements of particle mass relative to ambient by factors ranging between 30 and 70. Therefore, condensed water even in very thin clouds can be measured with high precision and accuracy.

Instrument Type
Laser absorption,
Spectrometer (in situ)
Measurements
H2O (total)
Aircraft
Gulfstream V - NSF,
C-230 - NSF,
DC-8- AFRC
Point(s) of Contact
Linnea Avallone
(PI),
Darin Toohey
(POC; PI)
Range of Measurement
In situ
Measurement Sampling Rate
45.00 Hz
Data Delivery
Real time (preliminary); 6 months (final)
Power:
150.00 W
(maximum
300.00 W
)
Location
Standard PMS wing canister
Mission-Specific Writeups
Publications

 

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