Spatial pattern of Land Surface Temperature over Umuahia North and Bende LGA, Abia State, Nigeria

U I Uchendu,K C Kanu,C Kanu,C I Mpamah

doi:10.36263/nijest.2019.02.0138

Abstract

This study evaluated the Spatial pattern of Land Surface Temperature (LST) over Umuahia North (Urban Area) and Bende LGA (Rural Area), Abia State, Southeast Nigeria. LANDSAT Imagery spanning Row 056 and Path 188, with 30m spatial resolution was captured on the 17th of May, 2018. Temperature and relative humidity were measured using a thermometer and multi-purpose Hydro-20 - 100 % model. Eight measurements were taken for each parameter at an interval of 8 hours at an elevation of 1.5m above the ground. Coordinates and elevation of the points were captured using a Garmin Handheld GPS. Data obtained were imported in compatible formats with ArcGIS 10.5 and the values for the un-sampled locations within the study area was determined through the interpolation of the collected data. A subset covering the study area was extracted for bands 1,2,3,4 and 5. Bands 1, 2 and 3 which are visible bands were used in generating a true colour composite image of the study area; the bands 4 and 5 which are not visible bands were used for the NDVI (Normalized Differential Vegetation Index). Result showed that Bende LGA had a vegetal cover of 45,741.26hectares out of a total of 60,152.76 hectares while Umuahia North had 19,689.09 hectares of vegetal cover out of a total of 24,459.75 hectares. Umuahia North had an average daily temperature of 31.309̊ C while Bende had 27.405̊ C. The average relative humidity in Bende LGA was 82.37% while Umuahia North was 67.274%. In conclusion, the study showed the existence of heat islands in the urban areas in Umuahia North LGA which was characterized by higher temperature but lower relative humidity. The heat island could be attributed to the gradual loss of vegetation cover and the increase in built-up environments in Umuahia North LGA.

Highlights

Urban population is increasing and the infrastructural development required often leads to higher building density, resulting in a lack of green spaces (Abdollah, 2012)
Analysis of the data showed higher temperature in Umuahia North LGA an urban area compared with Bende LGA a rural Area (Table 1)
Higher values were recorded in the morning and evening in Umuahia North LGA when compared to Bende LGA

Summary

Introduction

Urban population is increasing and the infrastructural development required often leads to higher building density, resulting in a lack of green spaces (Abdollah, 2012). In comparison with rural areas, urban areas are more prone to the risks of lack of green space. One of the effects of urbanization is the urban heat island effect (UHI) (Kleerekoper et al, 2012). Urban heat island is an urban area whose ambient temperature is higher than the surrounding rural areas due to human activities which increasingly use asphalt and modify land surfaces while decreasing the green spaces and evaporation surfaces (Mobaraki et al, 2012). Increased surface temperature from UHI effects impacts on air quality and environmental conditions. Higher temperature increases ozone production at ground level from volatile organic compounds emitted from the combustion of fossil fuels. Ground level ozone and elevated temperatures are hazardous to public health because it can cause respiratory and cardiovascular problems (Quattrochi and Lo, 2003)

Objectives

Methods

Results

Conclusion