Assessment Of The Effect Of Urbanization On The Thermal Comfort Over Some Parts Of Tanzania

Abstract

The study assessed the effect of urbanization on the thermal comfort over Dar es Salaam, Zanzibar and Tanga. The monthly mean dry bulb temperature, dew point temperature and wind speed for the period of 1980 - 2010 at 0600Z and 1200Z were collected from Tanzania Meteorological Agency (TMA) while the population data was obtained from National Bureau of Statistics. The thermal comfort index was calculated by using Wind Chill Index and Kawamura‘s Discomfort Index. The temporal and spatial variation of thermal comfort index was determined. The possible association between thermal comfort index and population was also discussed. Result from the study showed that thermal comfort index observed to be high and people feel uncomfortable most of the year except in June, July and August (JJA). The study revealed that thermal comfort index was highest over Tanga and lowest over Dar es Salaam during the month of February at 0600Z while observed to be highest over Zanzibar and lowest over Tanga at 1200Z. In the month of July the highest thermal comfort index was observed over Zanzibar and the lowest indicated over Dar es Salaam at 0600Z while at 1200Z the highest values was observed over Dar es Salaam and lowest over Tanga. The difference in the index values can be attributed to the different bioclimatic condition and topography of the three cities. Population data was correlated with thermal comfort index and was indicated that, weak positive relationship between thermal comfort index and population at morning (0600Z) and weak negative relationship at afternoon (1200Z). However, the study showed no significant relationship in population data and thermal comfort index. The growth of thermal discomfort index in three cites is driven highly by the continuous increase of buildings, paved roads, buses as well as the decrease of cultivated land rather than population.