Determination of Heat Stress in the Tropical Urban Area of Ibadan, Southwest Nigeria

Abstract

Diurnal Temperature Humidity Index (THI) and Wind Chill Index (WCI) in Ibadan (7.38⁰N, 3.93⁰E), an urban tropical station are presented. Diurnal variation of THI was shown to be a mirror image of WCI. Morning and evening THI mostly bring about comfortable sensation, with the exception of months with high temperature. People are mostly uncomfortable during the afternoon due to the afternoon THI values, except during July-August- September (middle of the wet season) when people feel partly comfortable in the afternoon. A series of the average afternoon values of THI for the period January to December 1998 and 2000 were also shown. The following annual cycles were found significant in the average afternoon THI variations: 360 days, 182, 120, 60-90 days, 25-40 and 11-13 days, using Fourier analysis. The year 1997 had the highest THI values, the other years in order of decreasing THI values were 1998, 2001, 1999 and 2000. No cold episode was recorded throughout the period of investigation.

Keywords: Temperature, humidity, wind chill index, comfortable, Fourier analysis, cold episode

International Journal of Natural and Applied Sciences, 5(3): 235-243, 2009