TEMPORAL ANALYSIS OF URBAN HEAT ISLAND IN IBADAN METROPOLIS

O. S. Durowoju, K. J. Samuel, B. W. Anibaba

Abstract



Considering the threat posed by the urbanization on health and wellbeing of the urban dwellers, this study analysed the temporal pattern of urban heat island (UHI) in Ibadan Metropolis. Data on minimum, maximum and mean monthly temperature were obtained from six weather stations for a period of twenty years (1999-2018). Hourly and daily data on these parameters were obtained from the online archives of ECMWF Re-Analysis (ERA Interim) and "World Weather Online" for a 40-day period to enable proper description of the diurnal characteristics of UHI intensity. On the average, a total of 40 average hourly and daily observations were collected and used to complement the data obtained from the ground TM stations. The entire study area was divided into 40 grid cells of 1 km x 1 km using the 'Fish-net' technique in the ArcGIS software. Results show that there are seasonal variations in temperature, with a higher trend during the dry season. It was also revealed that the UHI intensity was observed to be higher during night hours than afternoon hours (maximum up to 3.8˚C) and strongest during the dry season. There was a strong positive relationship between the mean annual UHI intensity and years considered and this was found to be statistically significant (r = 0.786; t 5.09, C =2.12, P ≤ 0.05) with 1999, 2013 value v and 2015 being the years of peak UHI values, indicating strong thermal contrast.UHI in the study area is increasing on various forms of temporal scales. UHI intensity tends to be weakest in wet season and strongest during the dry season with the average values of the magnitude of UHI slightly higher in the latter. This studytherefore recommends a massive control of migrants from the rural areas to the urban areas by improving the lots and quality of life of rural dwellers through the provision of basic social infrastructure and decentralization of nodal locations and commercial areas through the building of supermarkets, shopping malls and departmental stores in residential areas.

Keywords


Urban Heat Island (UHI), Temporal Pattern, Diurnal

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