Land Surface Temperature Extracts for Peri-Urban Heat and Rural Cool Troughs in Ghana

Divine Odame Appiah,Eric Kwabena Forkuo,John Tiah Bugri

doi:10.23953/cloud.ijarsg.274

Abstract

The objective of this paper is to analyze the land surface temperatures (LST) derived from three satellite images as a proxy for urban heat island potential, through a peri-urban heat troughs (PuHT) to rural cool troughs (RuCT) continuum, concepts largely overlooked in the literature, in the Bosomtwe district of the Ashanti region of Ghana. Four Landsat satellite images from 2002, 2008 Enhanced Thematic Mapper+ (ETM+) and 2014 Landsat 8 Operational Land Imager and Thermal Infrared Sensor (OLI/TIRS) were geo-referenced and processed for classification using the maximum likelihood classifier algorithm in ERDAS Imagine 13. Land Use and Land Cover (LULC) transition analysis was performed in ArcMap for ArcGIS 10.2. Results indicate that, in order of importance, recent fallows and grasslands along with built up/bare land and concrete surfaces have been increasing in terms of coverage. A corresponding surface reflectance translated into LST values ranging between a minimum of 24oC (297K) to a maximum of 53oC (326K). Changing LULC types correlated with the land surface temperature fluxes, creating the RuCT and PuHT. This result explains the relatively substantial peri-urban land use dynamics in the district. Future studies should develop threshold values for RuCT and PuHT temperatures.

Highlights

Land surface characteristics determine the amount of energy that is absorbed and emitted
This study proposes that, considering the relative rapidity with which rural landscapes are being converted into peri-urban land uses, with surface reflectance transforming into built-up and paved land uses, it is imperative to analyze the connections between Rural cool trough (RuCT) and the Peri-urban heat trough (PuHT) systems as potentially full-fledged heat island cell areas
The 2014 image shows that the Bosomtwe district had experienced appreciable levels of land cover changes in terms of increasing built-up/bare lands and concrete (BBC) surfaces (Tursilowati et al, 2012)

Summary

Introduction

Land surface characteristics determine the amount of energy that is absorbed and emitted. The reflectance and emission properties of land surface features determine the albedo that defines the percentage reflectance of solar energy from the earth surface (Ahrens, 2005). Land use and land cover (LULC) dynamics influence the ability of land surfaces to absorb or reflect solar radiation in varying proportions. In furtherance of handling LULC dynamics, previous studies have indicated that depending on the type of LULC obtained, it could be possible to extract surface moisture and temperature characteristics from LULC maps generated from Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER), Landsat, MODIS and others (Ahrens, 2005; Liu and Zhang, 2011 and Srivastava et al, 2010). The energy emitted by the LULC mosaic as indicated by its surface energy fluxes and atmospheric conditions, aids in determining the varying energy fluxes of land surfaces (Vlassova et al, 2014)

Objectives

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Results

Conclusion