Department of Geography-Journal Articles

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Journal Articles (Geography)

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    Assessment of surface water quality of inland valleys for cropping in SW Nigeria
    (Appl Water Sci, 2015-07) Aboyeji, Olatunji Sunday; Ogunkoya, Olayinka
    Inland valley agro-ecosystems which are a category of wetlands have potential for sustainable crop production relative to uplands. A major challenge to their utilisation in the study area is their heterogeneity in hydrology, morphology, soil types and agro-economy. The study assessed the surface water quality of three typologies of the agro-ecosystems—amphitheatre-like valley-heads (Am), valley-side (VS), and low depression (LD)—for cropping. Surface water of six sites were sampled during the wet and dry seasons. The physicochemical properties and metal concentrations of the samples were analysed. Descriptive statistics and water quality indices were used to assess the suitability of the waters of the agro-ecosystems for cropping. Results showed that the valleys have neutral to slightly alkaline waters. Values of physicochemical parameters are generally within the acceptable range for cropping. The concentration of major cations varied across the inland valley types, but exhibited similar characteristics within each valley. The dominance of the major cations is in the order of Na [Ca [K[Mg. ANOVA results indicated that there is no significant difference in the concentration of heavy metals across the valleys (F=2.044, p=0.138, a=0.05). Generally, most of the physicochemical parameters and trace metals have low concentrations and are non-toxic to plants. Values of water quality indices (sodium adsorption ratio, soluble sodium percentage, total dissolved solids and permeability index) indicated that the concentrations of minerals in waters across the valley typologies are generally within permis- sible limits for cropping.
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    Assessing conflict impacts on urban physical infrastructure:
    (International Journal of the Physical Sciences, 2011-12) Ayanlade, Sina; Orimoogunje, Oluwagbenga O. I.
    This paper used geographic information systems (GIS) technique to assess the impact of conflict on land use in Ile-Ife and Modakeke in Nigeria. There has been limited systematic research work in terms of mapping the impacts of the communal crisis on the land use pattern using GIS. Therefore, the major aim of this paper is to map the impact of communal conflict on land use with the aid of GIS. Global positioning system (GPS) was used to take the co-ordinates of the affected area. The GIS map produced more than six years after the last clash between both communities. The research team counted 53 houses that were totally destroyed and remained to be re-built or rehabilitated.
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    A GIS-Based Procedure for Downscaling Climate Data for West Africa
    (Blackwell Publishing Ltd, 2008-10) Akinyemi, Felicia; Adejuwon, James Oladipo
    Local studies aimed at assessing the impact of climate variability on crop yield at the individual farm level require the use of weather and climate data. These are often collected at points known as meteorological stations. In West Africa, meteorological stations are sparsely distributed and as a result, are often unable to satisfy the data requirements for such studies. One major problem arising from this is how to estimate values for locations where primary data is not available. General Circulation Models (GCMs) have recently been deployed for weather forecasting and climate change projections but the resolution of their outputs is low requiring downscaling. This article describes a GIS-based procedure for downscaling GCMs’ outputs for use in studies assessing the impacts of climate variability on crop yield at the farm level. The procedure is implemented with the Hadley Centre's GCM (HadCM2) data, although any other GCM can be used. Results in this study show that the model works best when representing drier months as compared to wet months in all three domains tested. For example, it estimated the rainfall for January (the driest month) better than that of July which is the peak of the rainy season in West Africa. There is also a north-south pattern influencing the accuracy of estimated rainfall distribution, with stations in the south better represented than those in the north. For the greater part of West Africa where similar climatic conditions persist as in Nigeria, this procedure can be considered suitable for interpolation and downscaling
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    A multi-perspective view of the effects of a pipeline explosion in Nigeria
    (International Journal of Disaster Risk Reduction, 2013-11) Makinde, E. O.; Eludoyin, Adebayo O; Salami, Ayobami T
    Vandalisation of petroleum pipelines is a major cause of pipeline fire disasters. However, except the number of deaths recorded, little information of the effects of such disasters on the environment is often reported in developing countries, and post-disaster remediation process is thus usually unmonitored or ineffective. This study investigated the effect of a major pipeline disaster in a rural environment in Nigeria from multi-date satellite imageries (orthophoto map, Landsat Enhanced Thematic Mapper Plus, ETM þand IKONOS), social and ecological surveys. Results showed that some of the affected settlements were within the pipeline corridor before the disaster, and pipeline vandalisa- tion was encouraged by one or more cases of faulty and exposed pipeline, deficient pipeline monitoring system, sabotage and readily available markets for siphoned oil. Ecological effects include loss of about 200 ha of vegetation resulting into significantly lower woody and herbaceous plant species in the affected regions than the adjacent plots. Significant proportion of the survivors also reported lower quality of groundwater (well water), air and streams, health problems (mainly abdominal pain) after they drank the well water and destruction of their crops and farmlands. The study concluded on the need for enforcement of the right-of-way laws on pipelines in Nigeria.
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    Seasonality in the daytime and night-time intensity of land surface temperature in a tropical city area
    (International journal of Science of The Total Environment, 2016-12) Ayanlade, Sina
    Variations in urban land surface temperature (LST) links to the surrounding rural areas result to urban heat island (UHI), which is a global problem challenging both cities in develop and developing countries. Satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS), covering the period between 2002 and 2013 were analysed to examine seasonal variability in the daytime and night-time intensity of urban heat island (UHI), using Lagos metropolitan city of Nigeria as a case study. Contribution index (CI) and landscape index (LI) were used to estimate the LST contributions from non-urban and urban areas to UHI and assess the relationship between the Normalized Difference Vegetation Index (NDVI) and LST. The LI showed that both non-urban and urban areas contribute greatly to strengthen the intensity of LST during the daytime (with LI b1.0) and much more during the daytime in the dry seasons (LI = 0.13 in the year 2013). The correlation analysis showed seasonal variation in the relationship (R 2 ) between NDVI and the LST for both day and night times. The highest R 2 values were recorded for daytime, especially during the wet season (R 2 N0.90), while R 2 were very low in the night-time especially during dry season. The study indicates that reduction in vegetal cover in Lagos urban areas altered the terrestrial thermal and aerodynamic processes hence resulted in an intensification of UHI in the metropolitan city.