Micro-Climate and Human Thermal Comfort at Maiduguri and Yola in North-Eastern Nigeria

Abstract

Heat index describes the combined effects of Temperature and Relative Humidity on the body. The Heat Index provides an apparent temperature felt by human body that cools slower at higher values of relative humidity due to reduction in the rate of evaporation. This paper examines the Thermal Comfort Index of Maiduguri and Yola using two (2) different models; namely Temperature-Humidity Index and Humidex.  Thirty years (1988 to 2018) temperature and relative humidity data obtained from the archives of the Nigerian Meteorological Agency were used for the study. These were subjected to some descriptive and inferential statistical analyses. Values for the two models (Temperature Humidity Index and Humidex) were also computed for each station. The temporal (monthly, seasonal and annual) variation of the thermal indices and meteorological variables were also assessed. The result indicated a peak for Temperature-Humidity Index at Maiduguri in May, while that of Yola occurred in April. On the other hand, Humidex had its maximum value in May for both Maiduguri and Yola. Furthermore, both the Temperature Humidity Index as well as Humidex have their lowest heat index values in January at the two study locations. Additionally, inter-annual characteristics of the two heat comfort models for both Maiduguri and Yola showed an upward trend during the study period (1998 – 2018). So also, the temperature anomaly manifested an impression of continuous and regular increase in temperature across the study areas and this was determined due the straight line obtained from the simple regression. Hence, it can be stated categorically that in evaluating the impact of heat index on outdoor comfort, it must be emphasized that changes in surface air temperature is not the only reason but instead changes in humidity also play a significant role.