Abstract:
Abstract: Presently, the urban heat island (UHI) phenomenon, and its adverse impacts, are becoming
major research foci in various interrelated fields due to rapid changes in urban ecological
environments. Various cities have been investigated in previous studies, and most of the findings
have facilitated the introduction of proper mitigation measures to overcome the negative impact of
UHI. At present, most of the mountain cities of the world have undergone rapid urban development,
and this has resulted in the increasing surface UHI (SUHI) phenomenon. Hence, this study focuses on
quantifying SUHI in Kandy City, the world heritage tropical mountain city of Sri Lanka, using Landsat
data (1996 and 2017) based on the mean land surface temperature (LST), the difference between the
fraction of impervious surfaces (IS), and the fraction of green space (GS). Additionally, we examined
the relationship of LST to the green space/impervious surface fraction ratio (GS/IS fraction ratio)
and the magnitude of the GS/IS fraction ratio. The SUHI intensity (SUHII) was calculated based on
the temperature difference between main land use/cover categories and the temperature difference
between urban-rural zones. We demarcated the rural zone based on the fraction of IS recorded,
<10%, along with the urban-rural gradient zone. The result shows a SUHII increase from 3.9 ◦C in
1996 to 6.2 ◦C in 2017 along the urban-rural gradient between the urban and rural zones (10 < IS).
These results relate to the rapid urban expansion of the study areas from 1996 to 2017. Most of the
natural surfaces have changed to impervious surfaces, causing an increase of SUHI in Kandy City.
The mean LST has a positive relationship with the fraction of IS and a negative relationship with the
fraction of GS. Additionally, the GS/IS fraction ratio shows a rapid decline. Thus, the findings of this
study can be considered as a proxy indicator for introducing proper landscape and urban planning
for the World Heritage tropical mountain city of Kandy in Sri Lanka.
