GCOS Reference Upper-Air Network


Field Measurements for Passive Environmental Remote Sensing, Chapter 3 - Frost point hygrometers


Dale F. Hurst, Masatomo Fujiwara, Samuel Oltmans,


by Elsevier at 2022


Water vapor measurements by frost point hygrometers (FPHs) carried aboard aircraft during the mid-1940s revealed the ubiquitous dryness of the stratosphere. It was not until the 1960s that a lightweight and compact FPH was developed for use on meteorological balloons, allowing water vapor vertical profiles to be measured in situ from the very wet surface layer to the extremely dry stratosphere. Though modern balloon-borne FPHs are very technologically advanced compared to the early instruments, the actual measurement principle has remained unchanged. Today, balloon-borne FPHs are routinely launched from a number of sites to detect water vapor changes in the upper troposphere and stratosphere. The vertical profiles of water vapor provided by balloon-borne FPHs have proven extremely useful in the evaluation of stratospheric water vapor measurements by satellite-based instruments, especially in refining the algorithms used to retrieve water vapor profile information from satellite radiance data. Two such examples are provided here.


Dale F. Hurst, Masatomo Fujiwara, Samuel Oltmans,
Chapter 3 - Frost point hygrometers,
Editor(s): Nicholas R. Nalli,
Field Measurements for Passive Environmental Remote Sensing,
Pages 37-55,
ISBN 9780128239537,