Ayansina Ayanlade

Assessing wetland degradation and loss of ecosystem services in the Niger Delta, Nigeria

The Niger Delta, being the most extensive freshwater wetland and aquatic ecosystem in West Africa, provides numerous services both to local people and to the West African economy. Ongoing environmental pressure exerted by large-scale oil extraction and illegal timber logging, however, are suspected to have had a substantial impact on the Delta’s ecosystems over the last decades. Knowledge on impact of these activities on the region’s wetlands now or in the past is scarce and patchy. To address this lack of knowledge, this study assesses spatiotemporal changes in two wetlands in the region by using satellite data from 1984 to 2011 and GIS methods. The results show that both wetlands have experienced substantial degradation, particularly with respect to the area of forest lost. Although comprehensive environmental protection laws were introduced in 1988, ecosystem services of up to US

Seasonality in the daytime and night-time intensity of land surface temperature in a tropical city area

65 million in value were lost over the study period. The introduction of new legislation in 2007, however, is potentially a first step towards a more ‘wise use’ of wetlands in Nigeria.

Evaluation of the intensity of the daytime surface urban heat island: how can remote sensing help?

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<1.0) 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)>0.90), 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.

Geospatial data infrastructure for sustainable development in sub-Saharan countries

This study aimed at using remote sensing methodology to assess the daytime surface urban heat island (SUHI) in Lagos metropolis. Several studies have examined the SUHI, using point data from meteorological stations. However, it has been shown in the literature recently that it is practically impossible to accurately value the intensity of SUHI from ground meteorological measurement due to heterogeneity and complexity of surface temperature over land. Therefore a time series of Landsat data, from 1984 to 2012, were used in the present study to assess spatial and temporal variability in the contribution of source and sink landscape to daytime SUHI in Lagos. This study uses remote sensing methods because Lagos has a strong heterogeneity of land surface characteristics; with several drainage, vegetation, built-up and soil between the coast and mainland, thus the land surface temperature (LST) changes rapidly in space and time. The results from this study show differences in the contribution of source and sink landscape to SUHI. The main findings from the results show that source landscape contributes positively to the intensity of SUHI in Lagos metropolis. The results show a general increase in mean LST during the periods of study from 1984 to 2012. The north-west (NW) zone of Lagos has highest LST compared to other zones. In 1984, the mean LST of NW zone was 300.53 K, but increased to 301.85 K in 2000 and 302.85 K in 2012. Although contributions from the landscapes differ by zones and time, much more intensified LST was noted in the NW zone of the city. The study find out that change in landcover has been the most important driver of intensified SUHI in Lagos metropolis. NW zone recorded the highest increased in built-up area throughout the years: 320.32 km2 in 1984, 535.28 km2 in 2000 and 630.70 km2 in 2012. This study demonstrates therefore that it is possible to assess spatial distribution and long-term temporal evolution of the LST in urban area, using remote sensing data. Also the results shows that remote sensing methods offer possibility for measuring LST over complete spatially averaged rather than point values. The results from this study further our understanding that not only the SUHI is frequent to cities in developed countries, but the effects are also obvious in several urban settlements in tropical countries.

Seasonal Variation of Malaria Parasite Density in Paediatric Population of North Eastern Nigeria

Abstract People are now using geoinformation for many different purposes and consequently one can confidently say that the need for geospatial data infrastructure (GDI) cannot be overstated in sub-Saharan Africa. Geospatial information (GI) is essential to socio-economic planning and development of sub-Sahara African countries. This paper therefore examines: GI during the last centuries in sub-Sahara Africa; recent paradigms in GDI in sub-Sahara Africa; the benefit of GDI to the African economy and the future of GDI in sub-Sahara Africa. This study discovered that most countries in sub-Saharan Africa did not have timely access to accurate geospatial data throughout the last centuries. This significantly hindered meaningful social and economic development. Development of GDI nonetheless, will enhance search and retrieval of geospatial data in Africa. This is one of the benefits that can be derived from implementing GDI in sub-Sahara Africa. Therefore, it is necessary to review cadastral survey laws and regulations so as to incorporate the use of recent geospatial equipment.

Utilization of Satellite Imaging and Information Communication Technology in Agricultural Information Dissemination in Nigeria

Malaria is a major cause of morbidity and mortality in children and adults in the Sudano Sahel of Northeastern Nigeria with the highest prevalence of malaria in pregnancy of 64.5 in Nigeria recorded in this region. This study was carried out in 2003 and 2004 to provide parasitological baseline data for the development of Malaria Early Warning System (MEWS) for the surveillance of type I epidemic caused by meteorological conditions and to provide data for timing malaria key vector control measures such as Indoor Residual Spraying (IRS) for maximum effect. Clinical information about malaria cases were used in this study. In all 692 children aged 6 to 96 months were screened for Plasmodium infection and used for the analysis. The results showed that the majority of infected children (68.06%) were aged 12-60 months and their asexual parasite density (ap/ u1) was between 100-500 ap/u1 of the whole blood. The month of September recorded the highest Geometric Mean Asexual-Densities (GMPD) of 13,655 while the lowest parasite densities were observed at the peak of the dry season, especially during the months of March and April. Significance difference (p<0.05) was observed between the sexes in infection rate. It is obvious that male children have higher infection rate (about 67.5%), than while female children (32.5%) regardless of climate seasonality. Designing a malaria early warning system and providing baseline parasitological data for timing of spraying cycles for key malaria vector control measures such as Indoor Residual Spraying (IRS) should be encouraged to complement other effective malaria control strategies. Hence the need for this investigation.

Geo-Political Patterns of Health Care Facilities in Kogi State, Nigeria

This study appraised the level of usage of satellite imaging and selected Information Communication Technology (ICT) tools by agricultural extension workers (EWs) in the North Central Zone of Nigeria. Specifically, information on usage of satellite imaging, personal skill ratings, and constraints faced by respondents in the usage of ICT equipment were gathered. Findings revealed that a majority of the respondents (97%) perceived themselves as incompetent in reading and interpreting satellite imaging for agricultural information dissemination. The study posited that government at various levels should assist in training EWs on digital compatibility.

Seasonal rainfall variability in Guinea Savanna part of Nigeria: a GIS approach

This study is about the distribution of health care facilities in Kogi State within the context of the geography and politics of the state. Hence, the study analyses the spatial patterns of health care facilities among the three senatorial districts (which corresponds to the division along major ethnic lines) in the state. Also, the ownership structure of facilities and the relationship between population and distribution of health care facilities in the state are analysed. The list of health care facilities and ownership in Nigeria obtained from the Department of Health Planning and Research, Federal Ministry of Health served as database for the analysis of the spatial patterns of distribution and ownership of health care facilities in Kogi State. Also, the National Population Commissions census figures provided information on the population of the State. Kogi State was stratified into the three existing senatorial districts - Kogi Central, Kogi East, and Kogi West. The total number of health care facilities and their ownership in each stratum were determined and used for the analyses. Data show that there exist inequalities in the distribution of HCFs among the various senatorial districts in the state. Kogi east senatorial district recorded the highest concentration of HCFs having 66.3% of all HCFs in the state, followed by Kogi west (19.6%) and Kogi central (14.1%). It is observed that the facility-population ratios for both PHC and SHC (1:2575 and 1:29024 respectively) are high. These proportions vary among the various senatorial districts; for example PHC-population ratios were 1:6850, 1:2746 and 1:1689 for Kogi central, west and east respectively; the ratios for SHC were 1:41,859, 1:27804 and 1:23736 for Kogi central, west and east respectively. Although, the government dominates the ownership of health care facilities in the state, her impact is heaviest in Kogi east where she owns 93% of HCFs as opposed to 70% in Kogi central where the impact is least. Kogi east which has produced the civilian Chief Executives of the state since its creation in 1991 ranks far ahead of the two other districts in the distribution of HCFs. Appropriate authorities should endeavour to achieve a more equitable distribution of health care facilities in the state, so as to engender equity and social justice.

Remote sensing approaches for land use and land surface temperature assessment: a review of methods

Purpose – This paper aims to use geographical information systems kriging interpolation technique to examine and map the spatiotemporal variation in rainfall in Guinea Savanna of Nigeria.Design/methodology/approach – Rainfall data, for the periods between 1970 and 2000, are collected from the archives of the Nigerian Meteorological Services, Oshodi Lagos. In this paper, rainfall is considered as the primary and input for crop yield. It is observed that the most important climatic element is rainfall; particularly inter‐annual variation and the spatiotemporal distribution of rainfall. Three spatial interpolation methods are chosen for this research work: inverse distance weighting method and the spline (completely regularized) as the determinist methods; and ordinary kriging as the stochastic methods. In order to analyze the interpolation quality, an evaluation by cross validation has been carried out. Ordinary kriging method was discovered suitable for this paper because it allows the sharpest interpolati...

Environmental impacts of oil production in the Niger Delta: remote sensing and social survey examination

ABSTRACT Selection of appropriate data and methods for environmental change assessment is highly central in any remote sensing research project. This study assessed various land use/land cover change (LUCC) methods and tested the accuracy of prominent classification methods and their implications on land surface temperature (LST) change estimation. Niger Delta of Nigeria was used as a case study. The study concluded that, though no single method can be applied to all cases and regions, there are some factors that determine the remote sensing methods to be used in both LST and LUCC change analysis. Such factors include the spatial, temporal, spectral and radiometric resolutions of satellite image and environmental factors. Therefore, this paper evaluated methods used in earlier studies to assess, monitor and model LUCC impacts on LST. The paper concludes by proposing the use of two or more methods in any LUCC–LST research project. This is because, all remote sensing methods are not totally right, but some are useful, thus, the methods should be viewed as complementary.