scholarly journals Spatiotemporal Variation of Urban Heat Islands for Implementing Nature-Based Solutions: A Case Study of Kurunegala, Sri Lanka

2020 ◽  
Vol 9 (7) ◽  
pp. 461 ◽  
Author(s):  
Manjula Ranagalage ◽  
Sujith S. Ratnayake ◽  
DMSLB Dissanayake ◽  
Lalit Kumar ◽  
Hasula Wickremasinghe ◽  
...  
Keyword(s):  
Climate Change ◽  
Sri Lanka ◽  
Google Earth ◽  
Spatiotemporal Variation ◽  
Urban Systems ◽  
Positive Temperature ◽  
Impervious Surfaces ◽  
Mitigation And Adaptation ◽  
Urban Heat ◽  
The Mean

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.

scholarly journals Quantifying Surface Urban Heat Island Formation in the World Heritage Tropical Mountain City of Sri Lanka

2018 ◽  
Vol 7 (9) ◽  
pp. 341 ◽  
Author(s):  
Manjula Ranagalage ◽  
DMSLB Dissanayake ◽  
Yuji Murayama ◽  
Xinmin Zhang ◽  
Ronald C. Estoque ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Green Space ◽  
World Heritage ◽  
Heat Island ◽  
Impervious Surfaces ◽  
Tropical Mountain ◽  
The World ◽  
Urban Rural ◽  
Urban Heat ◽  
The Mean

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.

scholarly journals Comments about Urban Bioclimate Aspects for Consideration in Urban Climate and Planning Issues in the Era of Climate Change

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 546
Author(s):  
Andreas Matzarakis
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Urban Climate ◽  
Heat Island ◽  
Adaptation Measures ◽  
Mitigation And Adaptation ◽  
Urban Heat

In the era of climate change, before developing and establishing mitigation and adaptation measures that counteract urban heat island (UHI) effects [...]

The role of climate information for the urban transition towards sustainability

2020 ◽  
Author(s):  
Gaby Langendijk ◽  
Diana Rechid ◽  
Daniela Jacob
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Urban Systems ◽  
Heat Island ◽  
Climate Information ◽  
Urban Transition ◽  
Urban Heat

&lt;p&gt;Urban areas are prone to climate change impacts. A transition towards sustainable urban systems is relying heavily on useful, evidence-based climate information on urban scales.&amp;#160;&lt;/p&gt;&lt;p&gt;However, many of the urban climate models and regional climate models are currently either not scale compliant for cities, or do not cover essential parameters and/or urban-rural interactions under climate change conditions. Furthermore, although e.g. the urban heat island may be better understood, other phenomena, such as moisture change, are little researched. Our research shows the potential of regional climate models, within the EURO-CORDEX framework, to provide climate information on urban scales for 11km and 3km grid size. The city of Berlin is taken as a case-study. The results show that the regional climate models simulate a difference between Berlin and its surroundings for temperature and humidity related variables. There is an increasing urban dry island in Berlin towards the end of the century, as well as an increasing urban heat island. The study shows the potential of regional climate models to provide climate change information on urban scales.&lt;/p&gt;&lt;p&gt;For climate information to underpin the urban transition this information will need to be put in a decision-making context. As an example, the research aims to understand connections to the health sector on how to integrate the information in order to manage e.g. the dispersion of pollen in cities, assisting in mitigating pollen allergies. The research showcases an interdisciplinary way forward to firstly produce climate information on urban scales and secondly how to connect it to city sectors in a suitable manner to underpin the transition to sustainable urban systems.&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals CLIMATE CHANGE CHALLENGES FACING SRI LANKA: A LITERATURE REVIEW

2021 ◽  
Author(s):  
S.P.M. Dasandara ◽  
◽  
U. Kulatunga ◽  
M.J.B. Ingirige ◽  
T. Fernando ◽  
...  
Keyword(s):  
Climate Change ◽  
Sri Lanka ◽  
Literature Review ◽  
Climate Change Impacts ◽  
Future Research ◽  
Mitigation And Adaptation ◽  
Adverse Weather ◽  
Temperature Levels ◽  
Earth’S Climate ◽  
The Many

The earth’s climate has changed throughout history and climate change can be identified as an inevitable phenomenon which is being experienced by the whole world. When considering the Sri Lankan context, it is no different to the global context in that the country’s climate has already changed. Sri Lanka, being an island state, is vulnerable to many climate change impacts including high-temperature levels, adverse weather events, sea level rising, and changes in precipitation patterns. The many challenges that arise from these climate-related issues are projected to continue through this century and beyond. Thus, climate change mitigation and adaptation have become the most appropriate ways to restrain these climate change challenges in Sri Lanka. It is paramount to get a broad understanding of how disastrous these climate change challenges are, prior to implementing appropriate responses to overcome them. This urges the need for conducting an in-depth investigation of prevailing climate change challenges in Sri Lanka. Thus, this study presents the prevailing climate change challenges facing Sri Lanka through a conceptual framework, that has been developed based on the existing literature. The developed framework reveals how these prevailing climate changes can lead to a number of challenges. These challenges were identified under three main categories as economic, social, and environmental challenges. The knowledge generated through this literature review will be the focus of future research.

scholarly journals Urbanization, Climate Change and Environmental Resilience: Experiences in Sri Lanka

2021 ◽  
Vol 4 (1) ◽  
pp. p46
Author(s):  
Mangala De Zoysa
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Sri Lanka ◽  
Urban Heat Island ◽  
Urban Forestry ◽  
Extreme Weather ◽  
Heat Island ◽  
Sustainable Urbanization ◽  
Urban Heat ◽  
Policy Setting

Urbanization in conjunction with climatic change affecting urban life and pose challenges to cities worldwide creating urban residents increasingly vulnerable to extreme weather and other natural disasters. Improvement of urban ecosystems provide cost-effective solution against negative impacts of climate change accelerated with high population pressure and promote resilience of urban dwellers. The cities in Sri Lanka are focused on improving land use planning and management of urban forest ecosystems for adaptation to and mitigation of climate change impacts with the rapid urbanization. This study attempts to ascertain the effects of urbanization, analyze the impacts of urbanization and climate change, and examine the environmental resilience with urban forests in Sri Lanka, reviewing the relevant literature. This paper explore the effects of urbanization in terms of increase population, land use change, rising greenhouse gas emissions and intensity of urban heat island. The impacts of urbanization and climate change are revealed as change of annual rainfall, urban warming, extreme weather events, and urban health hazards. Disaster resilient cities, sustainable urbanization, greening the cities, other environmental resilience strategies as well as institutional and policy setting are discussed for environmental resilience to urbanization and changing climate. Limiting CO2 emission, reducing land surface temperature, and controlling urban heat island effect are discussed under the other environmental resilience strategies. Institutional and policy setting is explained through popularizing urban forestry and developing policy support. Urban forestry strategies incorporating urban planning should be manifested in urban development policy in order to counteract the negative effects of climate change in the process of environmental resilience and sustainable urbanization.

scholarly journals Landscape Changes and their Impacts on Land Surface Temperature in Tropical Hill Stations in South Asia: A Case Study of Nuwara Eliya, Sri Lanka

2019 ◽  
Author(s):  
Manjula Ranagalage ◽  
Yuji Murayama ◽  
DMSLB Dissanayake ◽  
Matamyo Simwanda
Keyword(s):  
Land Use ◽  
Sri Lanka ◽  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Google Earth ◽  
Rural Zone ◽  
Urban Rural ◽  
The Mean ◽  
Grid Based

Although urbanization has contributed to improving living conditions, it has had negative impacts on the natural environment in the urbanized areas. Urbanization has changed the urban landscape and resulted in increasing land surface temperature (LST). Thus, studies related to LST in various urban environments have become a popular research topic. However, few LST studies focusing on the mountain landscapes (i.e. hill stations) have been carried out. The primary objective of this study is to investigate changes in the landscape and their impacts on LST intensity (LSTI) in the tropical mountain city of Nuwara Eliya, Sri Lanka. The study utilized annual median temperatures extracted from Landsat data collected from 1996 to 2017 based on the Google Earth Engine (GEE) interface. The fractions of built-up (BL), forest (FL), and agricultural (AL) land were calculated using land use and cover maps based on the urban-rural zone (URZ) analysis. The urban-rural margin was demarcated based on the fraction of BL (&lt;10%) and LSTI was measured using the mean LST difference in the urban-rural zone. In addition, the mixture of land use types was calculated using the AL/FL and BL/FL fraction ratios, and grid-based density analysis. The result shows that the BL in all URZ rapidly developed, while AL decreased during the period 1996 to 2017. There was minimal change in the forest area of the Nuwara Eliya owing to the government forest preservation policies. The fraction of the BL increased from 32.4% in 1996 to 58.7% in 2017 in the city center zone (URZ1) resulting in increased mean LST by 4.7 &deg;C. Furthermore, the increase of the BL/FL fraction ratio and the decrease of the AL/FL fraction ratio were positively correlated with the mean LST. Grid-based analysis showed an increasing positive relationship between mean LST and density of BL. This indicated that BL density has been a crucial element in increasing LST in the study area. The results of this study will be a useful indicator to introduce improved landscape and urban planning in the future to minimize the negative impact of LST on urban sustainability.

scholarly journals The Impact of Climate Change on Urban Thermal Environment Dynamics

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1159
Author(s):  
Igor Žiberna ◽  
Nataša Pipenbaher ◽  
Daša Donša ◽  
Sonja Škornik ◽  
Mitja Kaligarič ◽  
...  
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Heat Waves ◽  
Thermal Environment ◽  
Urban Systems ◽  
Climate Change Scenarios ◽  
Heat Island ◽  
Urban Heat ◽  
Urban Thermal Environment ◽  
The Impact

The human population is increasing. The ongoing urbanization process, in conjunction with climate change, is causing larger environmental footprints. Consequently, quality of life in urban systems worldwide is under immense pressure. Here, the seasonal characteristics of Maribor’s urban thermal environment were studied from the perspectives of surface urban heat island (SUHI) and urban heat island (UHI) A remote sensing thermal imagery time series and in-situ measurements (stationary and mobile) were combined with select geospatial predictor variables to model this atmospheric phenomenon in its most intensive season (summer). Finally, CMIP6 climate change scenarios and models were considered, to predict future UHI intensity. Results indicate that Maribor’s UHI intensity maximum shifted from winter to spring and summer. The implemented generalized additive model (GAM) underestimates UHI intensity in some built-up parts of the study area and overestimates UHI intensity in green vegetated areas. However, by the end of the century, UHI magnitude could increase by more than 60% in the southern industrial part of the city. Such studies are of particular concern, in regards to the increasing frequency of heat waves due to climate change, which further increases the (already present) heat stress in cities across the globe.

How to assess ecodistrict resilience to urban heat stress under future heatwaves? A case study for the city of Paris

2020 ◽  
pp. 11-24
Author(s):  
Anaïs Machard ◽  
Simon Martinez ◽  
Emmanuel Bozonnet ◽  
Eleonora Lacedra ◽  
Christian Inard
Keyword(s):  
Climate Change ◽  
Heat Stress ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Mitigation Strategies ◽  
Anthropogenic Sources ◽  
New Paradigm ◽  
Mitigation And Adaptation ◽  
Urban Heat

It is now well-known that the frequency, intensity and duration of heatwaves will strongly increase along the XXIth century, which introduces the urban built environment resilience as a new paradigm. In Paris, the intense 2003 heatwave demonstrated that warm urban temperatures could result in serious adverse health issues. Temperatures were particularly elevated during nighttime, due to the urban heat island effect. Since air-conditioning has not penetrated yet in residential French buildings, studying the potential of combined mitigation strategies at the district and building scale to increase the neighbourhood and buildings resilience in strong urbanized areas under future heatwaves is a key subject matter. The climate change aspect is integrated through a future heatwave weather file, re-assembled from dynamically downscaled multi-year regional climate change projections from the EURO-CORDEX project. The new ecodistrict Clichy-Batignolles in central Paris is chosen as a case study, recognized as innovative for low-energy and environmental solutions. It is composed of high-rise residential and commercial buildings, large green areas, cool surfaces, and reduced anthropogenic sources. We used an Urban Canyon Model (Urban Weather Generator) to model the neighbourhood and different design configurations (building height and density, green and cool surfaces). The designs and measures were evaluated through a sensitivity analysis to analyse their potential to mitigate the urban local microclimate air temperature during the heatwaves. We quantified the neighbourhood resilience and found that the ecodistrict is exposed to a strong urban heat stress under the future intense heatwave. These results highlight how outdoor overheating assessment can be used to evaluate the district mitigation and adaptation strategies. This approach can be used for urban planning, while the modelled future urban heatwaves can be used as an input for building simulations and evaluate the resilience of the buildings to urban heat stress.

scholarly journals Climate Change Policy Evaluation and Its Impact on Island Nations: Case Of Singapore And Sri Lanka

2019 ◽  
Vol 6 (2) ◽  
pp. 23-37
Author(s):  
Osada Vishvajith Peiris
Keyword(s):  
Climate Change ◽  
Sri Lanka ◽  
Policy Evaluation ◽  
Action Plan ◽  
Climate Change Policy ◽  
Negative Influence ◽  
Economic Sectors ◽  
Mitigation And Adaptation ◽  
Change Policy ◽  
Policy Measures

Climate Change (CC) is universally recognized as a major global threat due to its nature of impacts. Island nations are known to be the most vulnerable to CC impacts where many countries have initiated mitigation and adaptation actions through sector-based policy measures. Singapore and Sri Lanka are two Asian island nations with CC induced threats. Two countries are different in terms of economic development, but similar developing countries in the CC agenda. In this context, both the countries have initiated mitigation and adaptation actions through policy measures. This study compares the key climate driven performance indicators with historical data to evaluate the performance of climate change policy of each country. Generally, policy evaluation has been conducted by adopting scientific and non-scientific tools, but it is seldom see that the relation of climate driven indicators along with CC policy. Also the policy research was mostly based on European case studies and Asian island nations were not easy to find in this context. The comparison of two countries in terms of CC policy is to determine the key vulnerable sectors where intervention is necessary for island nations. Mitigation policies are evaluated in Singapore and Sri Lanka using GHG emission pathways under twelve (12) indicators and adaptation policies are measured under the national expenditure of key sectors of the economy under seven (07) indicators. The analysis further elaborated by comparing both countries with key economic sectors that has positive and negative influence on CC impacts. Finally, the analysis outcome is used for lessons to learn from each other in improving the CC policy of Singapore and Sri Lanka. As every country has a unique set of strategies to minimize contributions to CC impacts, unique features that are common to both countries are chosen as variables for the comparison. Policy recommendations are provided to implement solid action plan for post 2020. The study expects to assist island countries to strengthen the CC policy as a national priority to manage unforeseen impacts posed by CC phenomena

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