Assessing theValue ofUrbanGreen Spaces inMitigatingMulti-SeasonalUrban Heat usingMODISLand SurfaceTemperature (LST) andLandsat 8 data

Document Type: Original Research Paper

Authors

School ofAgricultural, Earth and Environmental Sciences, University ofKwaZulu-Natal, P. Bag X01, Scottsville, 3209 Pietermaritzburg, SouthAfrica

Abstract

Urban growth and associated landscape transformation has been a major driver of local, regional
and global environmental change. The conversion of urban greenery to impervious landscapes has been identified
as a key factor influencing the distinctive urban heat and associated consequences. Due to the often high
demand for space in urban areas, creation and preservation of urban greenery as heat sinks is commonly
perceived as “a waste of space”. Consequently, there is an increasing need for creation and preservation of
such spaces. This study sought to quantify multi-seasonal heat contribution of major Land-Use-Land-Cover
(LULC) within the Ethekwini Municipal Area (EMA) using the recently launched Landsat 8 and MODIS -
Land Surface and Temperature (LST) data-sets. To determine the contribution of urban greenery as possible
remedy to Urban Heat Island (UHI), major LULCs were grouped into four functional zones and Contribution
Index (CI) used to determine multi-seasonal heat contribution to EMA. Results show that impervious surfaces
were the major heat source while the green spaces were the major heat sinks. Furthermore, the built-up/green
spaces transition zones accounted for significantly lower heat contribution to the entire landscape. The latter
finding indicates the value of developing greenery mosaics within the often densely built-up urban areas. In
addition to determining extents of EMA’s valuable greenery, this study demonstrates the value of remotely
sensed data-sets in understanding the implication of LULC types on the urban micro-climate. The study is
particularly valuable for designing sustainable urban socio-economic and environmental strategies at local,
regional and global climate change

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