EN-SCI Cryogenic Frost
Point Hygrometer

A sonde that accurately and precisely measures water vapor at elevations from the earth’s surface to the mid-stratosphere.


Applications
  • To study the upper and lower troposhpere.
  • Measure the amount of water vapor inside ice clouds
  • Dehydration studies (particularly in the tropical upper troposphere)
  • Validation of satellite measurements and radiosonde humidity sensors

Advantages
  • Measure water vapor at the parts-per-million level
  • Avoid the costs associated with aircraft-mounted instruments
  • Simple operation
  • Lightweight design with minimal power requirements
  • Can be launched with small balloons
  • Perform accurate measurements during ascent as well as descent
  • Software included for easy monitoring of the CFH unit
  • Compatible with EN-SCI ECC Ozonesondes

How it Works

The CFH operates by maintaining a small mirror at the precise temperature necessary to generate a thin, constant layer of condensate on the mirror. When this layer exists, the mirror temperature is the same as the ambient frost or dew point temperature. An LED emits light that is reflected off the mirror, and a photodetector senses this reflected light, which varies with the amount of frost present. The photodetector signal is then used to adjust the mirror temperature. The mirror is heated with a heater coil and/or cooled with a cryogenic liquid. These mechanisms allow the mirror to be heated and cooled quickly so that its temperature reflects the current frost or dew point.

Product Details

Product Details

Specifications

ParameterSpecification
Measured ParametersAmbient Frost Point
Derived ParametersRelative Humidity, Mixing Ration
TechniqueTemperature-controlled chilled mirror
Uncertainty Measurement4% in tropical lower troposphere,
10% in middle stratosphere,
9% in tropopause
Altitude Range0 - 25 km (all climates)
Weight< 400 g (without coolant)
Instrument Dimensions7.6 cm x 7.6 cm x 13.3 cm
Dimensions (in Flight Box)~12" W x 12" D x 12" H (~39cm x 39cm x 39cm)
*Product information is subject to change without notice.

Included Items

  • EN-SCI CFH Sonde 
  • Polystyrene Foam Flight Box
  • Lithium Metal Batteries
  • Inlet Tubes
  • Technical Support

Warranty

EN-SCI warrants this product to be free of defects in material and workmanship for up to one year from the shipped date or first flight, whichever comes first. For support assistance please email us at info@en-sci.com.

Preparation Equipment

( Sold Separately ) 

Published  Articles 

Published  Articles

Absolute accuracy of water vapor measurements from six operational radiosonde types launched during AWEX‐G and implications for AIRS validation

Miloshevich, L. M., H. Vömel, D. N. Whiteman, B. M. Lesht, and F. J. Schmidlin (2006). “Absolute accuracy of water vapor measurements from six operational radiosonde types launched during AWEX and implications for AIRS validation,” Journal of Geophysical Research, 111, D09S10, doi:10.1029/2005JD006083.

Increase in lower-stratospheric water vapor at a mid-latitude Northern Hemisphere site from 1981 to 1994

Oltmans, S. J., and D. J. Hofmann (1995), “Increase in lower-stratospheric water vapour at a mid-latitude Northern Hemisphere site from 1981 to 1994,” Nature, 374, 146– 149.

Tropical cirrus clouds near cold point tropopause under ice supersaturated conditions observed by lidar and balloon-borne cryogenic frost point hygrometer

Shibata, T., H. Vömel, S. Hamdi, S. Kaloka, F. Hasebe, M. Fujiwara, and M. Shiotani (2007), “Tropical cirrus clouds near cold point tropopause under ice supersaturated conditions observed by lidar and balloon-borne cryogenic frost point hygrometer,” Journal of Geophysical Research, 112, D03210, doi:10.1029/2006JD007361.

Accuracy of tropospheric and stratospheric water vapor measurements by the cryogenic frost point hygrometer: Instrument Details and Observations

Vömel, H., D. E. David and K. Smith (2007). “Accuracy of tropospheric and stratospheric water vapor measurements by the cryogenic frost point hygrometer: Instrument Details and Observations.” Journal of American Geophysical Research, Vol. 12, D08305, doi:10.1029/2006JD007224.

Intercomparisons of stratospheric water vapor sensors: FLASH-B and NOAA/CMDL frost point hygrometer

Vömel, H., V. Yushkov, S. Khaykin, L. Korshunov, E. Kyrö , and R. Kivi (2007). “Intercomparisons of stratospheric water vapor sensors: FLASH-B and NOAA/CMDL frost point hygrometer.” J. Atmos. Ocean. Technol, Vol. 24, doi: 10.1175/JTECH2007.1.

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member of HMEI

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JH Acquisitions LLC d.b.a. EN-SCI © 2018 | Website created by Rumsey Design

JH Acquisitions LLC d.b.a. EN-SCI © 2018
Website created by Rumsey Design

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