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Title: Cryogenic Frostpoint Hygrometer (CFH) Instrument Handbook

Abstract

The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Cryogenic Frostpoint Hygrometer (CFH) is a small, balloon-borne instrument that provides highly accurate measurements of water vapor in the atmosphere. The CFH, although highly modified, is based upon the National Oceanic and Atmospheric Administration (NOAA)/Climate Monitoring and Diagnostic Laboratory (CMDL) frostpoint hygrometer (FPH) that has been flown in Boulder, Colorado, since 1980. The CFH has a significantly greater sensitivity to water vapor than standard radiosondes, as it can measure the frostpoint or dewpoint temperatures at an accuracy better than 0.2 K corresponding to water volume mixing ratios accuracies of only a few parts per million. The main instrument part is a small mirror, which is cooled by a cryogen in order to be covered with a thin layer of water vapor condensate. A pair of photodiodes detects the condensation on the temperature-controlled mirror. The phase of the condensate is controlled by a force-freezing algorithm, allowing for clear interpretation of the dew point versus frostpoint. The replacement of analog electronics with a microprocessor, a feedback controller, and thermistor calibration have led to improved accuracy and performance of the CFH over its predecessors. Further characteristics like reduced power consumptionmore » and low instrument weight made the CFH a successful instrument to perform in situ balloon-borne measurements of water vapor in the upper troposphere and lower stratosphere. CFH measurements are now used worldwide to validate radiosonde, satellite, and ground-based profiler measurements.« less

Authors:
 [1];  [1]
  1. University of Alaska, Fairbanks (United States)
Publication Date:
Research Org.:
DOE Office of Science Atmospheric Radiation Measurement (ARM) Program (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
Contributing Org.:
University of Alaska, Fairbanks (United States)
OSTI Identifier:
1427705
Report Number(s):
DOE/SC-ARM-TR-210
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 47 OTHER INSTRUMENTATION; Southern Great Plains; dewpoint; radiosonde; water vapor

Citation Formats

Stuefer, Martin, and Gordon, Telayna. Cryogenic Frostpoint Hygrometer (CFH) Instrument Handbook. United States: N. p., 2018. Web. doi:10.2172/1427705.
Stuefer, Martin, & Gordon, Telayna. Cryogenic Frostpoint Hygrometer (CFH) Instrument Handbook. United States. https://doi.org/10.2172/1427705
Stuefer, Martin, and Gordon, Telayna. 2018. "Cryogenic Frostpoint Hygrometer (CFH) Instrument Handbook". United States. https://doi.org/10.2172/1427705. https://www.osti.gov/servlets/purl/1427705.
@article{osti_1427705,
title = {Cryogenic Frostpoint Hygrometer (CFH) Instrument Handbook},
author = {Stuefer, Martin and Gordon, Telayna},
abstractNote = {The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Cryogenic Frostpoint Hygrometer (CFH) is a small, balloon-borne instrument that provides highly accurate measurements of water vapor in the atmosphere. The CFH, although highly modified, is based upon the National Oceanic and Atmospheric Administration (NOAA)/Climate Monitoring and Diagnostic Laboratory (CMDL) frostpoint hygrometer (FPH) that has been flown in Boulder, Colorado, since 1980. The CFH has a significantly greater sensitivity to water vapor than standard radiosondes, as it can measure the frostpoint or dewpoint temperatures at an accuracy better than 0.2 K corresponding to water volume mixing ratios accuracies of only a few parts per million. The main instrument part is a small mirror, which is cooled by a cryogen in order to be covered with a thin layer of water vapor condensate. A pair of photodiodes detects the condensation on the temperature-controlled mirror. The phase of the condensate is controlled by a force-freezing algorithm, allowing for clear interpretation of the dew point versus frostpoint. The replacement of analog electronics with a microprocessor, a feedback controller, and thermistor calibration have led to improved accuracy and performance of the CFH over its predecessors. Further characteristics like reduced power consumption and low instrument weight made the CFH a successful instrument to perform in situ balloon-borne measurements of water vapor in the upper troposphere and lower stratosphere. CFH measurements are now used worldwide to validate radiosonde, satellite, and ground-based profiler measurements.},
doi = {10.2172/1427705},
url = {https://www.osti.gov/biblio/1427705}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {3}
}