A humidity climatology for Halley, Antarctica, based on frost-point hygrometer measurements

Measurements of humidity at a height of 4 m were made at Halley Research Station between 1995 and 1997 using a frost point hygrometer. Relative humidities were usually close to ice saturation, particularly during the winter, but ice supersaturations of up to 20% were frequently measured. Supersatura...

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Bibliographic Details
Published in:Antarctic Science
Main Authors: King, J.C., Anderson, P.S.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 1999
Subjects:
Online Access:http://dx.doi.org/10.1017/s0954102099000139
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102099000139
Description
Summary:Measurements of humidity at a height of 4 m were made at Halley Research Station between 1995 and 1997 using a frost point hygrometer. Relative humidities were usually close to ice saturation, particularly during the winter, but ice supersaturations of up to 20% were frequently measured. Supersaturation with respect to liquid water was rarely observed. During the summer, diurnal variation in temperature drove a daily cycle in relative humidity, although corresponding variations in mixing ratio were comparatively small. It is suggested that the high frequency of ice supersaturations and almost total absence of water supersaturation results from the high abundance of condensation nuclei relative to ice nuclei.