Fast-Response Humidity Measurements with the Psychrometric Method

Abstract

A simple method for correcting the time series of a wet temperature sensor characterized by slow response is presented in this paper. A first-order linear approximation of the heat transfer equation is used for correcting the wet temperature measurements. The sensor cutoff frequency is found by an easy experimental method using the phase spectrum between the wet temperature sensor and a much faster platinum thermometer under low wind speeds (up to 3 m s?1) and relatively dry atmosphere (relative humidity 20%?40%). If such a correction is applied, the wet sensor output along with the computed vapor pressure time series using the psychrometric equation are considerably recovered.