Assessing the Impacts of Urban Green Areas on Mitigating Urban Heat Island Effect: The Case of Addis Ababa, Ethiopia

Lamma, Samson Warkaye (2016) Assessing the Impacts of Urban Green Areas on Mitigating Urban Heat Island Effect: The Case of Addis Ababa, Ethiopia. Masters thesis, Addis Ababa University.

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Abstract

Several studies have been conducted on analyzing the land surface temperature since 1970’s other than Ethiopia in detail. Urban Heat Island (UHI) is the variation in Land Surface Temperature (LST) between the urban realm and the surrounding rural areas. Urban areas are experiencing large population density, an increase surface temperature and expansion of built­up environment, which this intern affects the micro­climate of the city and develops UHI. With regard to surface temperature, different parameters and data’s were used to understand the situation, to examine its effect and for determining a solution to overcome the consequences. Input data’s such as Landsat TM (Thematic Mapper), ETM+ (Enhanced Thematic Mapper Plus) and Landsat 8 OLI – TIRS (Operational Land Imagery – Thermal Infrared Sensor) images, after conducting radiometric and geometric corrections, were used to produce results for analysis. For generating LST of the study area, using Landsat Satellite data, Single and Split Window Algorithms were applied. Measurement techniques, NDVI (Normalized Difference Vegetation Index), LST (Land Surface Temperature), NDBI (Normalized Difference Built­up Index) and Land­use/Land­cover were produced to examine the UHI effect and the positive influence of green areas. The result in correlating the LST and NDVI indicates that, more than 76% of the variability of the LST is due to the distribution of NDVI throughout the study area. Therefore, NDVI as indicator to LST is acceptable, because, it results in strong correlation. The maximum LST in the four base years (1985, 1995, 2006 and 2015), with slight decrease in 1995, it shows a gradual increment in the measured LST and area coverage. In 1985, the area under 17⁰C surface temperature covers 0.95km2, 17–21⁰C covers 22.94 km2 and 61.6% of the area received temperature between 27–31⁰C. The result also shows, the higher the value of the NDBI is the higher the LST. A dramatic land­use/land­cover change exhibited from 1985 to 2015. In 1985 the built­up covers 25.7%, in 1995 about 40.8, in 2006 was 48.31 and in 2015 become 59.64%. On the other hand, vegetation cover is decreasing from 16.6% to 9.54% for the year 1985 and 2015, respectively. Measured temperature in the selected public parks and surroundings, indicates that, there is a maximum of 5⁰C temperature increment. Urban Public Parks plays a major role in mitigating the Urban Heat Island Effect. Therefore, a proper planning should be considered by government and stakeholders for administering and developing green areas and individuals keep the surrounding green.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	NDVI, NDBI, LST, UHI, Land-use/Land-cover.
Subjects:	H Social Sciences > H Social Sciences (General) Q Science > QE Geology Q Science > QK Botany
Divisions:	Africana
Depositing User:	Selom Ghislain
Date Deposited:	06 Sep 2018 14:29
Last Modified:	06 Sep 2018 14:32
URI:	http://thesisbank.jhia.ac.ke/id/eprint/4958

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