Quantification of Atmospheric Humidity Variability using Fourier Transform

Abstract

In this paper, the methodology of the TEVY index is used to quantify the variability of atmospheric relative humidity during a year. Like the TEVY index, the variability of humidity is quantified by calculating the deviations between the observed values and the values derived from harmonic Fourier analysis. Two meteorological stations with different climatic characteristics are used for this analysis, Florina station, which is located in the northern part of Greece, and Tympaki station, which is located in the southern part of Greece. The results show that there is an increasing trend in variability of relative humidity over time for both stations, with Florina showing a higher increase. Furthermore, the extreme values of relative humidity show that the number of days with a relative humidity of less than 40% increases sharply over the course of a year. On the other hand, the days with extremely high relative humidity values (over 90 %) show a decreasing trend over the course of a year, indicating that we are moving towards generally drier conditions.