scholarly journals Characterization of the urban microclimate by the modelling of urban planning policies in France

2021 ◽  
Vol 2042 (1) ◽  
pp. 012065
Author(s):  
Magalie Técher ◽  
Hassan Ait Haddou ◽  
Rahim Aguejdad
Keyword(s):  
Urban Planning ◽  
Urban Heat Island ◽  
Urban Form ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Urban Microclimate ◽  
Heat Islands ◽  
Urban Heat ◽  
The Impact ◽  
Planning Policies

Abstract With the increase of Urban Heat Islands (UHI) and the effects of global warming, cities will face challenges in anticipating these phenomena. However, the complexity of urban development within the framework of urban planning policies, makes difficult for urban decision-makers to anticipate the Urban Heat Islands within their territory. In this paper, we propose a methodology to assess the impact of urban planning policies on Urban Heat Island. Thanks to a coupling of 2D urban growth model, 3D constructability model and urban microclimate simulation, this tool will make it possible to visualize the impact of urban planning decisions on urban form and on Urban Heat Island.

Synergistic Interactions between Urban Heat Islands and Heat Waves: The Impact in Cities Is Larger than the Sum of Its Parts

2013 ◽  
Vol 52 (9) ◽  
pp. 2051-2064 ◽  
Author(s):  
Dan Li ◽  
Elie Bou-Zeid
Keyword(s):  
Urban Heat Island ◽  
Rural Areas ◽  
Urban Areas ◽  
Heat Waves ◽  
Mitigation Strategies ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Heat Islands ◽  
Urban Heat ◽  
The Impact

AbstractCities are well known to be hotter than the rural areas that surround them; this phenomenon is called the urban heat island. Heat waves are excessively hot periods during which the air temperatures of both urban and rural areas increase significantly. However, whether urban and rural temperatures respond in the same way to heat waves remains a critical unanswered question. In this study, a combination of observational and modeling analyses indicates synergies between urban heat islands and heat waves. That is, not only do heat waves increase the ambient temperatures, but they also intensify the difference between urban and rural temperatures. As a result, the added heat stress in cities will be even higher than the sum of the background urban heat island effect and the heat wave effect. Results presented here also attribute this added impact of heat waves on urban areas to the lack of surface moisture in urban areas and the low wind speed associated with heat waves. Given that heat waves are projected to become more frequent and that urban populations are substantially increasing, these findings underline the serious heat-related health risks facing urban residents in the twenty-first century. Adaptation and mitigation strategies will require joint efforts to reinvent the city, allowing for more green spaces and lesser disruption of the natural water cycle.

scholarly journals Comparative Analysis of Urban Heat Island Intensities in Chinese, Russian, and DPRK Regions across the Transnational Urban Agglomeration of the Tumen River in Northeast Asia

2018 ◽  
Vol 10 (8) ◽  
pp. 2637 ◽  
Author(s):  
Bing Li ◽  
Zhifeng Liu ◽  
Ying Nan ◽  
Shengnan Li ◽  
Yanmin Yang
Keyword(s):  
Urban Heat Island ◽  
Urban Agglomeration ◽  
Urban Heat Islands ◽  
City Size ◽  
Vegetation Coverage ◽  
Heat Island ◽  
Tumen River ◽  
Heat Islands ◽  
Urban Heat ◽  
The Impact

Quantification of the spatial pattern of urban heat island intensities across the transnational urban agglomeration of the Tumen River is important for the promotion of sustainable regional development. This study employed Landsat images and MODIS LST data obtained in 2016 to determine the intensity of urban heat islands in this region, enabling direct comparison of data from the sub-regions of China, Democratic People’s Republic of Korea (DPRK), and Russia. The average urban heat island intensity for the region was found to be 1.0 °C, with the highest intensity of 3.0 °C occurring during the summer time. The intensity of urban heat islands on the Chinese side was higher than on the other two sides, with city size, socio-economic development levels and vegetation coverage significantly affect their intensity. Urban heat island effects in Chinese cities in the region contribute increases in maximum summer temperatures and the number of high-temperature days that pose a threat to the health of their residents. The factors that influence urban heat island intensities in these cities and the impacts of urban heat island effects on the quality of life and health of residents are discussed. Therefore, it is desirable to reduce the impact of urban heat island effects on cities in the region by increasing the area of green spaces they contain, as well as controlling their size and population.

scholarly journals Effect of Land Cover Fractions on Changes in Surface Urban Heat Islands Using Landsat Time-Series Images

2019 ◽  
Vol 16 (6) ◽  
pp. 971 ◽  
Author(s):  
Tao Chen ◽  
Anchang Sun ◽  
Ruiqing Niu
Keyword(s):  
Land Cover ◽  
Urban Heat Island ◽  
Land Surface ◽  
Urban Heat Islands ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Impervious Surfaces ◽  
Heat Islands ◽  
Urban Heat ◽  
Surface Urban Heat Island

Man-made materials now cover a dominant proportion of urban areas, and such conditions not only change the absorption of solar radiation, but also the allocation of the solar radiation and cause the surface urban heat island effect, which is considered a serious problem associated with the deterioration of urban environments. Although numerous studies have been performed on surface urban heat islands, only a few have focused on the effect of land cover changes on surface urban heat islands over a long time period. Using six Landsat image scenes of the Metropolitan Development Area of Wuhan, our experiment (1) applied a mapping method for normalized land surface temperatures with three land cover fractions, which were impervious surfaces, non-chlorophyllous vegetation and soil and vegetation fractions, and (2) performed a fitting analysis of fierce change areas in the surface urban heat island intensity based on a time trajectory. Thematic thermal maps were drawn to analyze the distribution of and variations in the surface urban heat island in the study area. A Multiple Endmember Spectral Mixture Analysis was used to extract the land cover fraction information. Then, six ternary triangle contour graphics were drawn based on the land surface temperature and land cover fraction information. A time trajectory was created to summarize the changing characteristics of the surface urban heat island intensity. A fitting analysis was conducted for areas showing fierce changes in the urban heat intensity. Our results revealed that impervious surfaces had the largest impacts on surface urban heat island intensity, followed by the non-chlorophyllous vegetation and soil fraction. Moreover, the results indicated that the vegetation fraction can alleviate the occurrence of surface urban heat islands. These results reveal the impact of the land cover fractions on surface urban heat islands. Urban expansion generates impervious artificial objects that replace pervious natural objects, which causes an increase in land surface temperature and results in a surface urban heat island.

Emergence of opposite trends in daytime and night-time urban heat island intensities in England

2020 ◽  
Author(s):  
Eunice Lo ◽  
Dann Mitchell ◽  
Sylvia Bohnenstengel ◽  
Mat Collins ◽  
Ed Hawkins ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Urban Areas ◽  
Urban Land Use ◽  
Urban Heat Islands ◽  
Urban Heat Island Effect ◽  
Heat Island ◽  
Night Time ◽  
Heat Islands ◽  
Island Effect ◽  
Urban Heat

<p>Urban environments are known to be warmer than their sub-urban or rural surroundings, particularly at night. In summer, urban heat islands exacerbate the occurrence of extreme heat events, posing health risks to urban residents. In the UK where 90% of the population is projected to live in urban areas by 2050, projecting changes in urban heat islands in a warming climate is essential to adaptation and urban planning.</p><p>With the use of the new UK Climate Projections (UKCP18) in which urban land use is constant, I will show that both summer urban and sub-urban temperatures are projected to increase in the 10 most populous built-up areas in England between 1980 and 2080. However, differential warming rates in urban and sub-urban areas, and during day and at night suggest a trend towards a reduced daytime urban heat island effect but an enhanced night-time urban heat island effect. These changes in urban heat islands have implications on thermal comfort and local atmospheric circulations that impact the dispersion of air pollutants. I will further demonstrate that the opposite trends in daytime and night-time urban heat island effects are projected to emerge from current variability in more than half of the studied cities below a global mean warming of 3°C above pre-industrial levels.</p>

Urban Informal Housing and Surface Urban Heat Island Intensity

2018 ◽  
Vol 9 (2) ◽  
pp. 158-177 ◽  
Author(s):  
Surabhi Mehrotra ◽  
Ronita Bardhan ◽  
Krithi Ramamritham
Keyword(s):  
Heat Stress ◽  
Spatial Analysis ◽  
Urban Heat Island ◽  
Urban Form ◽  
Spatial Association ◽  
Heat Island ◽  
Urban Heat ◽  
Surface Urban Heat Island ◽  
The Impact ◽  
Slum Housing

Urbanization leads to the densification of built-up areas, and thereby increases surface heat island intensity which is one of the growing concerns in the rapidly urbanizing cities. Another notable aspect of cities like Mumbai is the uncontrolled growth of informal slum housing clusters, which have emerged as a significant urban built form in the landscape of cities. This study presents a case of Mumbai that aims to explore the linkages between slum housing—here referred as ‘slum urban form’ (SUF)—and surface urban heat island (SUHI) supported by spatial-statistical analysis. The magnitude of the impact of urban form on SUHI, measured by land surface temperature (LST), is examined using Cohen’s d index, which measures the effect size for two groups—SUF and ‘formal’ housing—on LST. The results confirm a ‘large’ effect indicating a significant difference in mean LST between the two groups. The spatial analysis reveals a statistically significant spatial clustering of LST and SUF ( p-value < 0.05), and bivariate local indicator of spatial association (LISA) confirms that the spatial association of SUF is surrounded by ‘high’ LST (Moran I: 0.49). The exploratory spatial analysis indicates that the contribution of SUF in elevating SUHI intensity is more than the formal housing areas and has increased vulnerability to heat stress. The results were validated on the ground using environmental sensors, which confirms the susceptibility of SUF to heat stress.

scholarly journals Changes in Urban Heat Island Effect with the Development of Newtowns

2021 ◽  
Author(s):  
Kyungil Lee ◽  
Yoonji Kim ◽  
Hyun Chan Sung ◽  
Seung Hee Kim ◽  
Seong Woo Jeon
Keyword(s):  
Urban Planning ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Heat Islands ◽  
Island Effect ◽  
Time Period ◽  
Before And After ◽  
Urban Heat ◽  
Planning Strategies ◽  
Short Time

Abstract Newtown is a planned city built over a short time period. It is suitable for climate and thermal research, particularly formulating urban planning strategies to analyse problems such as urban heat islands (UHIs). Herein, a comprehensive approach was demonstrated for determining changes in UHI distribution during 1989–2048 in two Newtowns with different urban planning. A significant increase in built-up areas was observed from 1989 (< 5%) to 2018 (> 40%) in both Newtowns. However, this increase significantly varied (approximately 12.25%) with urban planning in the areas where UHIs occurred before and after development. Moreover, without effective mitigation, the built-up area in each Newtown is estimated to increase to approximately 60%, and the surface UHI intensity in most areas to increase by 4 °C in 2048. Thus, these results combined with architectural assessment models can improve the understanding of thermal environmental impacts of urbanisation and help mitigate heat island hazards.

Evolutionary Consequences of the Urban Heat Island

2020 ◽  
pp. 91-110 ◽  
Author(s):  
Sarah E. Diamond ◽  
Ryan A. Martin
Keyword(s):  
Urban Heat Island ◽  
Urban Areas ◽  
Climatic Conditions ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Heat Islands ◽  
Physiological Tolerance ◽  
Downstream Effects ◽  
Urban Heat ◽  
Evolutionary Consequences

As humans continue to modify the climatic conditions organisms encounter, downstream effects on the phenotypes of organisms are likely to arise. In particular, the worldwide proliferation of human settlements rapidly generates pockets of localized warming across the landscape. These urban heat island effects are frequently intense, especially for moderate to larger sized cities, where urban centres can be several degrees Celsius warmer compared with nearby non-urban areas. Although organisms likely ameliorate the effects of warming through phenotypic plasticity, the evolution of thermally sensitive traits may be an important yet underappreciated means of survival. Recent work suggests the potential for contemporary evolutionary change in association with urban heat islands across a diverse suite of traits from morphology to physiological tolerance, growth rate, and metabolism. This chapter reviews and synthesizes this work. It first develops a comprehensive set of predictions for adaptive evolutionary changes in morphology, physiology, and life-history traits driven by urban heat islands. It then evaluates these predictions with regard to the burgeoning literature on urban evolution of thermally sensitive traits.

scholarly journals Analysis of the urban heat island in representative points of the city of Bayeux / PB

2018 ◽  
Vol 7 (6) ◽  
pp. 345
Author(s):  
Amanda Mayara Paulino Da Silva
Keyword(s):  
Land Use ◽  
Urban Heat Island ◽  
Thermal Field ◽  
Urban Climate ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Thermal Discomfort ◽  
Heat Islands ◽  
Urban Heat ◽  
The City

Abstrat Urban growth has generated several socio-environmental problems and has altered the quality of life of people living in these environments. Due to the disorderly growth of cities and the various forms of urban land use and occupation, changes in the thermal field of these areas have occurred and caused the formation of urban heat islands and thermal discomfort in urban environments. Thus, the need to understand the formation of heat islands in these areas and the study of their causes and consequences grows. Given this context, the present work intends to study the urban climate of the city of Bayeux / PB, specifically the urban thermal field, and the formation of heat islands. For the accomplishment of the research, initially a bibliographical survey of the subject in question was made. Subsequently experimental points of meteorological data collection (temperature and relative air humidity) were defined in the metropolitan area of the city of João Pessoa, specifically in the municipality of Bayeux / PB. These points were defined based on the different types of land use and cover in the study area. The following experimental points were defined: a point in the center of the city of Bayeux / PB, another point on the banks of the BR230 direction Bayeux, and a reference point in a remnant of Atlantic forest. To obtain the urban heat island the reference point was used as a parameter of the climatic conditions of a natural environment. The data of temperature and relative humidity were collected through thermometers (HOBO U-10), which were placed on steel tripods (1.5 meters high) and monitored at uninterrupted intervals of 1 and 1 hour during the dry period and rainy region. The analysis of the data points to the formation of urban heat islands in the two periods evaluated in the city of Bayeux / PB, being the center of the city, the most critical area with the most intense heat islands. The vegetative cover played a predominant role in the climatic mitigation of the experimental samples as well as the presence of precipitation. The areas with impermeable soil cover presented the largest heat islands and contributed to the thermal discomfort of the study area. Keywords: Urban Climate, Thermodynamic Field, Urban Heat Island.

scholarly journals Identification of Urban Heat Islands &Its Relationship withVegetation Cover: A Case Study of Colombo & Gampaha Districts in Sri Lanka

2019 ◽  
Vol 8 (2) ◽  
Author(s):  
G.M.T.S. Fernando
Keyword(s):  
High Temperature ◽  
Surface Temperature ◽  
Urban Heat Island ◽  
Land Surface Temperature ◽  
Vegetation Cover ◽  
Land Surface ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Heat Islands ◽  
Urban Heat

Global Warming is a major environmental problem that all kind of organisms has been affected at present. Urban Heat Island (UHI) is one of primary impacts of Global Warming. UHI is a phenomenon that the temperature of urban area is higher than surrounding rural areas or suburban areas. This increasing trend of temperature in urban areas affects many environmental entities such as air quality, water resources, habitats behaviors and climate changes. The most remarkable incident that relate with UHI is the difference of thermal properties of the surfaces. Many countries experience the consequences of Urban Heat Islands in many aspects such as economic, health, social and environmental affects. Thus to mitigate such impacts of UHI, it is very important to identify the main reasons behind this. In this paper UHIs in Colombo, Gampaha Districts and the relationship between UHI and vegetation cover were analyzed based on Landsat 8, 30m resolution data. Land Surface Temperature was derived from Landsat thermal Infrared band through several equations of United State Geological Survay (USGS) guidelines using Arc GIS 10. Conversion of Digital Number (DN) values to Top of Atmosphere (TOA) Radiance, Conversion of TOA Radiance to Satellite Brightness temperature and final calculation of Land Surface Temperature considering land surface emissivity are the steps that had been done for the analysis. Vegetation cover was derived by using vegetation index with the Red and Near Infra Red bands. The result shows that the land high surface temperature directly relates with the urbanized regions where vegetation cover is very less. High temperature difference could be identified that cause to arise the urban heat island effects in Colombo & Gampaha districts. There is a strong linearly negative correlation with correlation coefficient value of -0.742 between land surface temperature and vegetation cover. 78.8 km2 (including water) of total area had been identified as NDVI value less than 0.1. And extent of high temperature area was 74.12 km2 where temperature more than 27oC at 10.22am. The area in temperature range of 25-27 was 464.95km2 and area in NDVI value range 0.1-0.2 was 333.04 km2. 1471.1 km2 was identified as NDVI value between 0.3-0.4 and the area at low temperature was 1529 km2where temperature less than 25oC. According to this results, high temperature at non-vegetated areas and low temperature at vegetated areas could be noted very clearly. This is probably due to the ecological function of vegetation that lay down the surface temperature from high evapotranspiration. Vegetated areas are mostly sensed with surface temperature.Thus research output can be useful for policy-makers and planners of development projects such as Western province Megapolis project as well as for general public to understand the urban heat island effects and importance of vegetation cover to mitigate such impacts.

Estimating and mapping urban heat islands of the UK by interpolation from the UK Met Office observing network

2020 ◽  
Vol 41 (5) ◽  
pp. 521-543 ◽  
Author(s):  
K Chowienczyk ◽  
MP McCarthy ◽  
D Hollis ◽  
E Dyson ◽  
M Lee ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Climate Data ◽  
Geographical Differences ◽  
Heat Islands ◽  
Urban Rural ◽  
Urban Heat ◽  
Temperature Observations ◽  
The Uk

In this paper, we estimate the climatological impact of urbanisation in the UK as derived from the present and historical set of temperature observations from the UK network of meteorological observing stations. A well-established method for interpolation of in-situ temperature observations is used to make an estimate of temperatures at urban weather station locations based on rural climate data. This method avoids reliance on simple pairing of urban–rural stations commonly used for station-based analysis, and explicitly accounts for other topographic features such as elevation and coastal effects that will introduce geographical differences in temperature. The method is then applied to select a network of ‘rural’ weather stations deemed to be largely free from the direct influence of urban micro-climate effects. Comparison of the temperature grids derived from the ‘urban’ and ‘rural only’ station sets enables quantification of climatological urban heat island intensity across the UK and the influence on temperature in the UK national observational network observations from urban stations. Practical application: This new method allows the estimation of the urban heat island for towns and cities of any size. Researchers will find it useful when making predictions of the urban heat island and of climate change in the urban environment, and when investigating morbidity and mortality due to overheating in buildings.

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