Trend analysis of Humidex as a heat discomfort index using Mann-Kendall and Sen’s slope estimator statistical tests

Background: The aim of this research was to assess the Humidex (HD) trends as a thermal discomfort index by analyzing meteorological data during a ۳۰ year period of summertime in Iran. Methods: For this purpose, data regarding average temperature and relative humidity were collected daily from ۴۰ different synoptic meteorological stations during a ۳۰-year statistical period (۱۹۸۵-۲۰۱۴). The HD index was calculated based on temperature and relative humidity according to an equation introduced by Masterton and Richardson. The Mann-Kendall and Sen’s slope tests were performed to analyze the changing trend of the HD. Results: Based on the findings, in ۷۲% of the meteorological stations, the HD followed an upward trend, so that ۴۰% of them was statistically significant. The changing trends in temperature during summertime throughout the studied years fluctuated greatly but generally, in many regions such as the arid, semi-arid, and humid regions, this trend was mostly incremental. Also, the changing trends in relative humidity in all regions was decremental throughout the years under study. Conclusion: The changing trend of the HD, which is based on temperature and humidity, was incremental in arid and semi-arid regions and decremental in the Mediterranean and humid regions.

Keywords:

Humidity , Temperature , Meteorology , Data analysis , Iran