Abstract:
The Colombo is the main commercial
metropolitan city in Sri Lanka with having highest population
and building density, making the city is more ideal place to form
Urban Heat Islands. This study was conducted to ecologically
evaluate the Urban Heat Island effect in Colombo city using
Landsat 8 satellite data. The temperature variation of the city
was acquired by Land Surface Temperature, a parameter
derived from Landsat 8, band10 (Thermal Infrared band),
band4 (Red band) and band5 (Near Infrared) using Radiative
Transfer Method. Evaluation of ecological condition was
assessed using Urban Thermal Field Variance Index, a
quantitative measurement of the urban ecological quality of life
with respect to Urban Heat Island effect. The model verification
was obtained by theoretical relationships between Surface
Temperature, Normalized Difference Built-up Index and
Normalized Difference Vegetation Index. Temperature
distribution in Colombo city revealed that, majority of the
environmentally critical areas were located near the harbor,
central business area along the main transport system and
coastal belt. According to above index, the city experiences two
extremes as areas of optimal micro-climate and areas with heat
stresses indicating the requirement of strong Urban Heat Island
mitigation measures in future landscape development and
urban planning of the city.
