Abstract:
Abstract: Changes in the urban landscape resulting from rapid urbanisation and climate change have
the potential to increase land surface temperature (LST) and the incidence of the urban heat island
(UHI). An increase in urban heat directly affects urban livelihoods and systems. This study investigated
the spatiotemporal variation of the UHI in the Kurunegala urban area (KUA) of North-Western
Province, Sri Lanka. The KUA is one of the most intensively developing economic and administrative
capitals in Sri Lanka with an urban system that is facing climate vulnerabilities and challenges of
extreme heat conditions. We examined the UHI formation for the period 1996–2019 and its impact
on the urban-systems by exploring nature-based solutions (NBS). This study used annual median
temperatures based on Landsat data from 1996 to 2019 using the Google Earth Engine (GEE). Various
geospatial approaches, including spectral index-based land use/cover mapping (1996, 2009 and 2019),
urban-rural gradient zones, UHI profile, statistics and grid-based analysis, were used to analyse the
data. The results revealed that the mean LST increased by 5.5 ◦C between 1996 and 2019 mainly
associated with the expansion pattern of impervious surfaces. The mean LST had a positive correlation
with impervious surfaces and a negative correlation with the green spaces in all the three time-points.
Impacts due to climate change, including positive temperature and negative rainfall anomalies,
contributed to the increase in LST. The study recommends interactively applying NBS to addressing
the UHI impacts with effective mitigation and adaptation measures for urban sustainability.
