No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
The Urban Heat Island Effect and City Contiguity
... Urban development has been identified as a primary contributor to elevated local extinction rates and human-induced habitat loss (McKinney 2006), with extensive associated environmental challenges, including air and water pollution (Bai et al. 2017), biotic homogenization (McKinney 2006), and habitat fragmentation (Wu et al. 2024). Furthermore, the phenomenon of light pollution (Seymoure et al. 2024), noise pollution (Barton et al. 2018), and the formation of urban microclimates, such as urban heat islands (UHIs) (Debbage andShepherd 2015, Herrera andCove 2020), are additional concerns that require attention. This is of particular significance in the context of urbanization, as temperature differences between urban and rural environments have been documented to reach up to 10°C (Wienert and Kuttler 2005). ...
... This is of particular significance in the context of urbanization, as temperature differences between urban and rural environments have been documented to reach up to 10°C (Wienert and Kuttler 2005). While high-density urban development, land clearances, and impervious surfaces can all contribute to the intensification of UHI effects (Debbage and Shepherd 2015), the presence of urban vegetation (green infrastructure) ) and waterbodies (blue infrastructure) can help mitigate the impact of these urban microclimates (Steeneveld et al. 2014). Despite calls for further research into the effects of microclimates on predation (Herrera and Cove 2020), there is a lack of studies that assess the extent to which urban microclimates impact trophic interactions. ...
Trophic interactions play a key role in maintaining ecological balance. In urban environments, avian predation has been demonstrated to be particularly important due to its effects on community structure, pest control, and nutrient cycling. As humanity relies upon ecosystem services for sustenance, and with 70% of the global population projected to reside in urban areas by 2050, understanding the impact of urbanization on avian predation is becoming increasingly important. This study investigates the impacts of urban microclimates, shaped by impervious surfaces and green/blue infrastructure, and human‐induced disturbances, on avian predation in urban areas, with the aim of testing the increased disturbance hypothesis. To assess the avian predation rate, plasticine caterpillars were placed in Quercus robur trees in the city of Amsterdam for a period of two months. The analyses evaluated the impact of artificial lighting at night, human population density, the urban heat island effect, impervious surfaces, vegetation, noise pollution, and water bodies on predation rates. The results indicated a substantial increase in predation during the second month, which was likely caused by an increase in naïve fledglings or elevated ambient temperatures. Noise pollution was identified as the most frequent and robust predictor of predation, consistently leading to a reduction in predation rates, possibly due to avoidance behavior. Other predictors exhibited substantial temporal and spatial variability. The variables related to urbanization increased predation in the initial month, suggesting that insectivorous birds prey on areas with higher illumination and temperature. However, the effect diminished in the subsequent month, potentially due to the increased daylight hours or a reduction in heating effects. During the second month, all predictors exhibited a negative effect on predation, thereby supporting the increasing disturbance hypothesis. These findings underscore the complex relationship between urban factors and avian predation, emphasizing the necessity for mitigation efforts in urban planning.
... Actions that maintain overall biodiversity in urban areas help protect species and habitats (Hall et al. 2017, Oliveira Hagen et al. 2017, Soanes and Lentini 2019 and confer benefits to humans that reside in urban areas via both physical and psychological ecosystem services. These ecosystem services may include pest reduction (Kunz et al. 2011, Aguiar et al. 2021, clean air and water (Chung et al. 2021), temperature regulation (Debbage and Shepherd 2015), aesthetic appeal (Tribot et al. 2018, Isik andVessel 2021), human health and safety (White et al. 2019), recreational opportunities (Shrestha et al. 2007), and community cohesion (Weinstein et al. 2015). Implicitly or explicitly, these values are often factored into urban planning, especially in communities that are sufficiently affluent to afford them (Park and Guldmann 2020), which often translates into a positive relationship between socioeconomic status and biodiversity, termed the "luxury effect" (Hope et al. 2003, Leong et al. 2018, Chamberlain et al. 2019. ...
... Consequently, areas with high probability of selection by S. varia could furnish broader conservation value through, for example, pest-reduction services provided by forest bats (Kunz et al. 2011), birds (Kellermann et al. 2008), and the owls themselves (Hindmarch and Elliott 2015). Importantly, areas preferred by S. varia may make good carbon sinks (Bastin et al. 2019) and reduce the island heat effect (Debbage and Shepherd 2015) because high preference was associated with features of mature forest. ...
We integrated GPS and accelerometer data to examine habitat selection and energy expenditure patterns across the diel cycle in Strix varia (Barred Owls), addressing a critical gap in wildlife research that often overlooks activity during the “inactive” phase. Owls in Baton Rouge, Louisiana, selected forests with tall canopies and open understories, particularly in affluent neighborhoods, supporting the “luxury effect” in urban biodiversity. Nocturnal home ranges were larger (31.8 ha) compared to diurnal home ranges (8.9 ha), indicating broader habitat use at night. The total area of preferred nocturnal habitat was 33% of the Baton Rouge study area, whereas preferred diurnal habitat comprised only 5%. Energy expenditure was inversely related to preference in nocturnal home ranges but increased with preference in diurnal home ranges. Our models were validated using independent data from Clemson, South Carolina, supporting the robustness of our analysis and revealing generalities in owl habitat selection across these regions. This research contributes to a deeper understanding of urban ecology, highlighting habitat components preferred by owls and possibly other forest-dwelling species. It emphasizes the difference in nocturnal and diurnal home range sizes, the scarcity of daytime refuges for S. varia in urban landscapes, and the variation in energy expenditure in preferred habitats. Our findings advocate for urban designs that accommodate wildlife activity throughout the day and night, and highlight the positive correlation between preferred owl habitat and affluent neighborhoods, underscoring the need for equitable distribution of green spaces to foster biodiversity across socioeconomic gradients. These insights will help develop strategies to enhance the ecological value of urban environments and the conservation of S. varia and associated forest-dwelling species in rapidly urbanizing areas.
... The polycentric form refers to the existence of multiple urban agglomerations with similar sizes at different levels of the urban hierarchy. There are no certain conclusions that polycentric urban spatial morphology has a better performance in decreasing LST than the monocentric form 27,45 . An investigation found that the polycentric form was beneficial for heat mitigation in China 44,46 . ...
... Some studies have inferred that the polycentric form may deteriorate the urban thermal environment 48 . Additionally, other scholars believe that the polycentric form has a limited influence on the SUHI 45,49 . Thus, it is necessary to further investigate the relationships between LST and monocentric/polycentric urban forms. ...
Urbanization combined with global climate change, exacerbates the urban thermal environment and hinders sustainable urban development. However, the complex relationships between land surface temperature (LST) and urban morphology are being further understood, particularly in relation to different urban development patterns, distinct topography, and 3D building morphology. Thus, this study conducted a comparative study in Chengdu and Chongqing, Southwest China. We explored the impact of comprehensive factors (including socio-economic factos, topography, land use composition, and building morphology) on LST by employing the methods of linear regression, geographical detector model, and the boosted regression trees. Our results suggest that (1) high LST was mainly observed in the central part of Chengdu but it presented multicenter aggregation trend in Chongqing; (2) Socio-economic factors were the dominant variables affecting LST in both cities; (3) land use composition and building morphology showed distinct contributions to LST among the two cities; and (4) 3D building management was more effective in Chengdu than in Chongqing. A better understanding of the impact of various influencing factors on LST will enable policy makers and planners to develop appropriate strategies for constructing climate-adaptive cities and mitigating urban heat.
... The urban heat island effect is a climatic phenomenon caused by the concentration of reflective surfaces and lack of vegetation, whereby cities store heat during the day and release it at night, thereby increasing the overall temperature (Guindon & Nirupama, 2015) (Fig. 1). Debbage and Shepherd (2015) reported that urban buildings are characterized by dense spreading. The highdensity layout can amplify the impact of the urban heat island effect (Debbage & Shepherd, 2015). ...
... Debbage and Shepherd (2015) reported that urban buildings are characterized by dense spreading. The highdensity layout can amplify the impact of the urban heat island effect (Debbage & Shepherd, 2015). The severe urban heat island effect can bring heat waves (Anderson & Bell, 2011), and a very destructive and extreme climate, to the city (Zhao et al., 2018). ...
In view of the energy shortage and climate warming that are caused by rapid urbanization, the energy structure that relies on traditional fossil fuels brings serious ecological problems, such as the urban heat island effect, acid rain, fog, and haze. To promote urban carbon emission reduction, energy saving, and quality improvement, it is urgent to change the energy structure and develop more new energies. This study provides a systematic review of domestic and international research on the urban heat island effect, its resulting hazards, and related research methods. The correlations between heat island effect and anthropogenic activities as well as energy structure were elucidated. Simultaneously, the deficiencies of the promotion trend of new energy in recent studies were put forward to the point. To promote the "double carbon" orientation based on the natural non-loss method, it provides a valuable reference for further alleviating a series of ecological problems caused by urbanization
... Urban areas, as major economic growth centers, attract almost 57% of the world's population, with 35% of that population being under 15 years old or over 65 years old [7]. In the future, cities are expected to remain highly attractive, with projections indicating that more than 67% of the population will reside in urban areas by 2050 [8]. Therefore, it is essential to explore the complex relationship between urban development and UHI effects, summarizing the various factors influencing the UHI effect and providing a quantitative basis for future urban planning and management. ...
... Figure 9 shows that the SUHII in the central area of the Guangzhou-Foshan metropolis is significantly higher than that in the surrounding areas, with the peak values of SUHII in 2013, 2018 and 2023 being 16.05 K, 15.20 K and 18.49 K, respectively. Similar to the research conducted in Wuhan, Nanjing, Changzhou, Chongqing, and Hefei, the LCZ types contributing the most to the SUHI effects were LCZ 2,3,4,5,8,and 10 [19,[77][78][79][80]. In the central part of the Guangzhou-Foshan metropolitan area, the SUHI effects were mainly driven by LCZ 2, 3, 4, and 5, which were primarily characterized by urban villages, residential areas, and old neighborhoods, such as the South Residential Block in Panyu District, old neighborhoods in Liwan District, and large urban villages in Yuexiu District. ...
Understanding the driving mechanisms behind surface urban heat island (SUHI) effects is essential for mitigating the degradation of urban thermal environments and enhancing urban livability. However, previous studies have primarily concentrated on central urban areas, lacking a comprehensive analysis of the entire metropolitan area over distinct time periods. Additionally, most studies have relied on regression analysis models such as ordinary least squares (OLS) or logistic regression, without adequately analyzing the spatial heterogeneity of factors influencing the surface urban heat island (SUHI) effects. Therefore, this study aims to explore the spatial heterogeneity and driving mechanisms of surface urban heat island (SUHI) effects in the Guangzhou-Foshan metropolitan area across different time periods. The Local Climate Zones (LCZs) method was employed to analyze the landscape characteristics and spatial structure of the Guangzhou-Foshan metropolis for the years 2013, 2018, and 2023. Furthermore, Geographically Weighted Regression (GWR), Multi-scale Geographically Weighted Regression (MGWR), and Geographical Detector (GD) models were utilized to investigate the interactions between influencing factors (land cover factors, urban environmental factors, socio-economic factors) and Surface Urban Heat Island Intensity (SUHII), maximizing the explanation of SUHII across all time periods. Three main findings emerged: First, the Local Climate Zones (LCZs) in the Guangzhou-Foshan metropolitan area exhibited significant spatial heterogeneity, with a non-linear relationship to SUHII. Second, the SUHI effects displayed a distinct core-periphery pattern, with Large lowrise (LCZ 8) and compact lowrise (LCZ 3) areas showing the highest SUHII levels in urban core zones. Third, land cover factors emerged as the most influential factors on SUHI effects in the Guangzhou-Foshan metropolis. These results indicate that SUHI effects exhibit notable spatial heterogeneity, and varying negative influencing factors can be leveraged to mitigate SUHI effects in different metropolitan locations. Such findings offer crucial insights for future urban policy-making.
... Each of these elements plays a critical role in the thermal dynamics of urban environments. The relationship between urban morphology, specifically building characteristics, and UHI proves intricate, as evidenced by studies acknowledging the nuanced interplay, such as Debbage and Shepherd (2015) proposing that increased urban spatial contiguity, shaped by building layout, amplifies the annual mean UHI, irrespective of whether the city is compact or sprawling. Building type and height play crucial roles in shading and wind flow patterns, which in turn affect local temperatures (Chun and Guldmann 2018;Erell, Pearlmutter, and Williamson 2012). ...
Buildings are among the dominant infrastructure in cities. playing critical roles in daily activities. This paper examines on the building structure factors that absorb and, in turn, emit heat into the urban microclimate, making cities urban heat islands that, in turn, contribute to global warming and climate change. Building materials are known for their heat absorption and emission properties. By identifying and minimising the heat absorption propensity of these materials, urban heat can be mitigated. This study focuses on identifying, ranking, and validating Building Structure Factors (BSFs) that influence heat absorption and emission, which contribute to the urban heat island effect, global warming, and climate change. This paper employed a hybrid methodology using the Fuzzy Delphi Method (FDM) and Confirmatory Factor Analysis (CFA) to identify key Building Structure Factors contributing to urban heat. The findings highlight four main criteria: building design and materials, energy efficiency and technologies, urban morphology, and vegetation and green features. The feasibility of the methods was demonstrated through the robust identification of actionable strategies for mitigating urban heat impacts. The findings offer valuable insights for urban planning and sustainable building practices, supporting efforts to reduce urban heat and enhance environmental resilience.
... emissions decreased [115,116]. While cities are critical contributors to climate change, they are simultaneously suffering from its consequences: enhanced anthropogenic emissions, lack of greenery, reduced wind velocities due to urban geometry, lower surface albedo and higher surface roughness as well as higher thermal storage leading to heat accumulation in cities and hence to a difference in ambient air temperature between urban and rural areas-the Urban Heat Island (UHI) effect [117][118][119][120]. Climate change as well as the increasing urban population will further foster the UHI effect, leading to intensified heat-related stress, increased mortality rates and morbidity in older people, and limited sleep recovery due to reduced night-time cooling [121]. ...
Climate protection and climate adaptation measures are essential to minimize global warming and to mitigate its effects. In cities however, available open space for these measures is scarce, while building envelopes provide large potentials for climate and energy activation through the use of photovoltaics and greenery. To date, these potentials have been largely untapped for two main reasons: First, negotiating solar and green strategies with redensification demands in an architecturally ambitious manner has only been partially addressed and no comprehensive solutions have been identified. Second, the use of photovoltaic modules as a new material for building envelopes raises the question of how these modules interact with the thermal microclimate. The interactions are diverse and to date they are not yet fully quantified.
The dissertation aims to address these research gaps through a multifaceted
methodological approach. First, a research by design process is used to negotiate building-integrated photovoltaics, building greenery and redensification measures. A subsequent systematic literature review provides an overview of the current state of research on the impact of photovoltaic installations on the surrounding thermal microclimate. Based on the findings of the literature review, the thermal impact of rooftop PV is quantified using a dual methodological approach with data provided by metrological investigations. The results are further complemented by simulation-based investigations that analyze the impact of photovoltaic facades on the surrounding thermal microclimate and human outdoor thermal comfort.
As a qualitative result of the research by design process, three design strategies with different emphases have been developed, providing urban planners with strategies for designing and negotiating the transformation of urban structures. The microthermal investigations lead to the following quantitative results: During the day, building-integrated PV moderately increase the surrounding ambient air temperature, the mean radiant temperature and the Universal Thermal Climate Index. At current PV system efficiencies, the conversion of solar radiation into electricity is not sufficient to offset the PV-induced increase in convective heat transfer. During the night, PV modules have a slight cooling effect on the thermal microclimate, due to their low heat storage capacity and the reduced heat dissipation of the surfaces beneath or behind the modules.
The results can contribute to negotiation processes in urban planning and hence promote a sustainable approach to architectural design with climate and energy active technologies, thus contributing to climate protection without neglecting human health.
... The purpose was to illustrate the mapping of estimated landscape pain, as a first step towards a more rigorously underpinned measuring of landscape pain emotions. The maps and the sources used are summarized in Table 3. Table 3. Mapping landscape pain and the sources used [106][107][108][109][110]. Fifth, the design phase of the research consisted of two parts. ...
In many conurbations, the pressure on the quality of living increases and affects the most vulnerable human and non-human populations the most. This article describes a proposal for the mapping and design investigation of how a green metropolis can be developed. The approach distinguishes between the landscape producing pain, the ways of healing, and the opportunities to create environments that people can love. This approach reveals concrete and widespread pain in the metropolis, such as impacts on natural landscapes (rivers and mountains), air pollution, ecological degradation, and hydrological disconnections. The strategy to remediate this pain is to uncover hidden and altered creeks and rivers, creating an abundant zone of ecological space around them before human activities and urbanization change the land uses. In addition to this, specific design principles have been developed for hydro-ecological corridors, water retention, green islands, and greenways. Designs for these places can be replicated to support a healing strategy in the Monterrey Metropolitan Area (MMA). Each place creates an environment that the urban residents will appreciate and preserve. The approach to analyzing landscape pain, designing healing strategies, and promoting local places of love can be applied to enhance the quality of life for many urban residents and non-human ecologies in metropolitan areas around the globe.
... This effect exerts negative impacts on the urban ecosystem. Studies have proved that the UHI effect results in air pollution and, hot wave phenomenon along with high energy consumption in urban areas (Debbage and Shepherd, 2015;Coseo and Larsen, 2014). Du et al. (2019) are of the view that mitigation of the UHI effect is a vital theme in both urban planning and landscape ecosystems. ...
... Enhancing relevant mitigation strategies at a macro level is therefore important. Reportedly, the spatial layout and connectivity optimisation of urban cool islands can significantly enhance the thermal environment (Debbage and Shepherd, 2015). Moreover, the establishment of a comprehensive and well-organised natural cooling network can effectively mitigate the adverse effects of intensive urban development and human activities (Peng et al., 2022). ...
Climate change has intensified urban heat risks through extreme heat and heat island effects. Using Fuzhou as a case study, we conducted assessments of heat risk and cool island quality to identify core heat risk sources (CHRSs) and core cold sources (CCSs). Based on the degree of resistance to surface heat transfer, we constructed a comprehensive resistance surface. This was followed by the construction of a composite cooling network using the minimal cumulative resistance and circuit theory models, along with the identification of key nodes to enhance the protection of cool island resources and ensure network stability. Our findings revealed that the central urban area had the highest heat risk, followed by the eastern coastal areas, showing a trend of further expansion towards the southeastern coast. Relatively high-quality cool island resources were distributed in the western mountainous area. We identified 21 CHRSs and 32 CCSs. The composite cooling network included 94 heat transport corridors and 96 cool island synergy corridors, with 148 cooling nodes and 78 barrier nodes. The average land surface temperature of transport and synergy corridors was 27.89°C and 25.34°C, respectively, significantly lower than the high-risk areas (31.14°C). Transport corridors enable heat transfer from CHRSs to CCSs, while synergy corridors can achieve further cooling by enhancing the synergy among cool islands.
... Sarah et al. assessed the UHI phenomenon in two Canadian cities, proposing an integrated approach to mitigation strategies and land use planning [27]. Debbage et al. employed gridded minimum temperature datasets and spatial indicators to quantify urban morphology in relation to the UHI effect [28]. Wang et al. conducted temperature distribution measurements along representative routes in Chongqing, utilizing isotherm analysis to study the city's UHI characteristics [29]. ...
In recent years, the intensification of the urban heat island (UHI) effect has become a significant concern as urbanization accelerates. This survey comprehensively explores the current status of surface UHI research, emphasizing the role of land use and land cover changes (LULC) in urban environments. We conducted a systematic review of 8260 journal articles from the Web of Science database, employing bibliometric analysis and keyword co-occurrence analysis using CiteSpace to identify research hotspots and trends. Our investigation reveals that vegetation cover and land use types are the two most critical factors influencing UHI intensity. We analyze various computational intelligence techniques, including machine learning algorithms, cellular automata, and artificial neural networks, used for simulating urban expansion and predicting UHI effects. The study also examines numerical modeling methods, including the Weather Research and Forecasting (WRF) model, while examining the application of Computational Fluid Dynamics (CFD) in urban microclimate research. Furthermore, we evaluate potential mitigation strategies, considering urban planning approaches, green infrastructure solutions, and the use of high-albedo materials. This comprehensive survey not only highlights the critical relationship between land use dynamics and UHIs but also provides a direction for future research in computational intelligence-driven urban climate studies. Keywords: urban heat island effect; land use; vegetation index; computational intelligence; urban expansion simulation; heat island effect prediction
... Urban planning must consider the factors affecting PCI when designing green spaces. Spatial arrangements, such as expansive and compact constructions, affect UHI intensity and PCI performance [121]. UHI increases temperatures, disrupts body regulation, causes heat strokes, dehydration, cardiovascular issues, and deteriorates air quality [122]. ...
Urbanization has significantly impacted the environment and urban life, with urban green spaces playing a crucial role in enhancing sustainability and public health. Urban Green Spaces (UGS) offer benefits such as temperature regulation, ecological services, and improved thermal comfort, while providing entertainment, culture, disaster avoidance, and ecological services. This study evaluates the cooling effects of UGS in mitigating the Urban Heat Islands (UHIs) phenomenon in Delhi, India, using satellite imagery to assess the Land Surface Temperature (LST) of 24 parks. We calculated the Park Cooling Intensity (PCI) by applying the mono-window algorithm. We found that parks larger than 1.55 hectares with dense vegetation and water bodies significantly reduced surrounding temperatures by up to 8.28 °C. The PCI effect was significantly influenced by park size, vegetation density, and the presence of water bodies, with larger parks and denser vegetation and water bodies demonstrating enhanced cooling capacity. These findings highlight the importance of integrating green spaces into urban planning as vital infrastructure for enhancing urban resilience, reducing heat-related health risks, and ensuring equitable access to public health benefits. The study also highlights the importance of addressing socio-economic disparities in park accessibility, which have significant implications for equitable urban development. This study emphasized the importance of formulating a strategic urban planning approach that focuses on green spaces' growth, conservation, and equitable allocation, thereby fostering eco-friendly, habitable, and robust urban environments.
... The urban 'heat island effect' (Debbage and Shepherd 2015) can strongly influence interactions between trees and pathogens (van Dijk et al. 2022), and facilitate the establishment of more thermophilic invasive species. While the latter process has mostly been shown for thermophilic insects (Branco et al. 2019) many bacterial forest pathogens including certain subspecies of X. fastidiosa are thermophilic as well, and might not only benefit from climate change, but also from the urban heat island effect. ...
Bacterial tree diseases have been mainly studied in agriculture and horticulture. For forest trees, damage due to bacterial diseases is understudied. Moreover, bacterial tree diseases often appear in the context of so-called complex diseases, which are dependent on other factors, such as multiple microorganisms, insects or abiotic factors which weaken the host. In recent years, outbreaks of bacterial tree diseases, such as Xylella fastidiosa in the Mediterranean region or acute oak decline (AOD) in the United Kingdom, raised the awareness of bacterial diseases on forest trees. In this review, we aim to summarise the current issues and available knowledge about bacterial diseases of forest trees in Central Europe. Furthermore, we identify potential bacterial pathogens that could gain importance in the future for central European forests. The methods used were a systematic literature search and the analysis of the data collected over the last 10 years on bacterial diseases by the Swiss forest protection service. We conclude that, on one side, complex bacterial diseases could increase in importance, especially considering ongoing climate change. Therefore, the bacterial community of diseased trees (the pathobiome) needs to be studied more in depth to understand the emergence of complex bacterial diseases. On the other side, host ranges of highly pathogenic invasive genera and species, such as Xylella, need to be investigated experimentally for common central European tree species and varieties, to implement proactive risk management strategies against bacterial diseases in forest trees. Finally, urban trees and green spaces should be monitored more closely, as they could serve as starting points for bacterial disease outbreaks in forests, similarly to other emerging diseases and pathogens.
... The Meteorological Observatory is based on the outskirts of Debrecen in an open field. In the city, the external temperature can be higher due to the urban heat island effect [20]; this can influence the number of summer, hot, and torrid days. Table 3 presents the external maximum air temperature frequency in the investigated period. ...
Energy consumption in buildings with large, glazed facades rises markedly in the summer, driven by cooling demands that vary with structural characteristics and external climate conditions. This study is unique in examining daily cooling needs in lightweight and heavyweight constructions, utilizing meteorological data from 782 summer days in Debrecen, Hungary. Unlike standard approaches, which often overlook localized meteorological variables, this analysis focuses on actual “clear sky” scenarios across distinct summer day types: normal, hot, and torrid. The findings indicate that orientation and construction type significantly affect cooling demands, with east-facing rooms demanding up to 14.2% more cooling in lightweight structures and up to 35.8% in heavyweight structures during peak hours (8 a.m. to 4 p.m.). This study reveals that for west-facing facades, extending use beyond 4 p.m. markedly increases energy loads. Furthermore, the cooling demand peak for heavyweight buildings occurs later in the day, driven by their higher thermal capacity. These insights underscore the importance of aligning HVAC system design with operational schedules and building orientation, offering data-driven strategies to enhance energy efficiency in buildings with diverse thermal and solar exposure profiles.
... In order to combat the SUHII while also controlling the expansion of large built-up areas, a balance must be struck between SUHII mitigation and economic growth through the development of satellite cities and new towns. Finally, it is advisable to diversify surface cover types and decrease the proximity of similar surfaces by incorporating parks, urban ventilation corridors, and other measures to break the spatial continuity of the city [107][108][109]. Additionally, adjustments to the industrial structure and optimization of population distribution are essential. ...
In the context of sustainable urban development, elucidating urban heat island (UHI) dynamics in arid regions is crucial. By thoroughly examining the characteristics of UHI variations and potential driving factors, cities can implement effective strategies to reduce their impacts on the environment and public health. However, the driving factors of a UHI in arid regions remain unclear. This study analyzed seasonal and diurnal variations in a surface UHI (SUHI) and the potential driving factors using Pearson’s correlation analysis and an Optimal Parameters-Based Geographic Detector (OPGD) model in 22 cities in Xinjiang, northwest China. The findings reveal that the average annual surface urban heat island intensity (SUHII) values in Xinjiang’s cities were 1.37 ± 0.86 °C, with the SUHII being most pronounced in summer (2.44 °C), followed by winter (2.15 °C), spring (0.47 °C), and autumn (0.40 °C). Moreover, the annual mean SUHII was stronger at nighttime (1.90 °C) compared to during the daytime (0.84 °C), with variations observed across seasons. The seasonal disparity of SUHII in Xinjiang was more significant during the daytime (3.91 °C) compared to nighttime (0.39 °C), with daytime and nighttime SUHIIs decreasing from summer to winter. The study also highlights that the city size, elevation, vegetation cover, urban form, and socio-economic factors (GDP and population density) emerged as key drivers, with the GDP exerting the strongest influence on SUHIIs in cities across Xinjiang. To mitigate the UHI effects, measures like urban environment enhancement by improving surface conditions, blue–green space development, landscape optimization, and economic strategy adjustments are recommended.
... In terms of optimizing the territorial spatial structure, we can implement measures that mitigate the thermal environment, such as increasing vegetation coverage and enhancing the water body index. Meanwhile, factors that exacerbate the intensity of the heat island, such as surface roughness, road density, and impervious surface ratio, should be minimized [37][38][39][40][41]. Additionally, altering the three-dimensional form of the city, such as adding urban ventilation corridors, can also be considered. ...
With the acceleration of urbanization, the rapid expansion of urban land use has led to an intensification and expansion of the urban heat island effect. This study focuses on the Changsha-Zhuzhou-Xiangtan region as the study area. Through geographical detectors, it analyzes the contribution intensity of land cover type data, DEM, GDP, and population density to the urban heat island. Using the CA-Markov model, it conducts a predictive analysis of land use conditions in the Changsha-Zhuzhou-Xiangtan region in 2025. Furthermore, based on the ANN-CA model, it predicts the intensity of the urban heat island in the Changsha-Zhuzhou-Xiangtan region for both 2025 and 2040. The results indicate that the proportion of construction land area, GDP, and DEM are the most influential factors contributing to the urban heat island. The prediction accuracy of the ANN-CA model for the urban heat island in 2015 and 2020, starting from 2000 and 2005, reached 86.12% and 94.8%, respectively, demonstrating the reliability of the ANN-CA model in predicting the urban heat island. Compared to 2020, the combined area proportion of strong and hot urban heat island regions in the Changsha-Zhuzhou-Xiangtan region increased by 1.04% in 2025 and 1.02% in 2040. During the period from 2020 to 2040, the heat island effect in the Changsha-Zhuzhou-Xiangtan region showed a slow increase, indicating that the heat island effect will be controlled to some extent overall.
... Mapping landscape pain and used sources[114][115][116][117][118]. ...
In many conurbations, the pressure on the quality of living increases and affects the most vulnerable, human, and non-human populations the most. In this article we describe a mapping and designing investigation how a green metropolis can be developed. The approach used is to make a distinction between the landscape pain, the ways of healing and the opportunities to create environments that people can love. We found that this approach reveals concrete and widespread pain in the metropolis, such as interventions in natural landscapes (rivers and mountains), air pollution, ecological degradation, and hydrological disconnections. The strategy to heal this pain is to uncover the currently hidden and invisible creeks and rivers, then create an abundant zone of ecological space around it before integrating human activities and urban uses. In addition to this, specific design principles have been developed for hydro-ecological corridors, water retention, green islands, and greenways. These places can be replicated to support the healing strategy. These places create an environment that the urban residents love. The analysis of landscape pain, the healing strategies, and the local places to love, can be applied to enhance the quality of life for many urban residents and non-human ecologies in metropolitan areas around the globe.
... In an increasingly urbanized world, understanding urban patterns of biodiversity takes on growing importance. Urban areas have more impervious cover, higher temperatures, and drier, more basic soils than non-urban areas (Oke 1982;Debbage and Shepherd 2015;Yang and Zhang 2015). These distinct abiotic conditions lead to corresponding differences in species diversity. ...
There are well documented differences in species diversity along urban-rural gradients, but the effects of urbanization on diversity within species are less well known. Nevertheless, intraspecific diversity is an important element of biodiversity that allows for adaptation and can affect community and ecosystem function. The amount of intraspecific diversity may differ along an urbanization gradient if urban areas filter for a very narrow range of traits or, alternatively, if selection is weaker or more spatially variable in urban areas and allows for a broader range of traits. To test the relationship between urbanization, trait means and intraspecific diversity in forested environments, we measured two traits in eight herbaceous understory plant species from nine populations across an urbanization gradient in Baltimore, Maryland, USA. We found that while impervious cover, soil moisture and soil pH were associated with changes in mean trait values of plants in different locations, there was little consistent effect of these abiotic conditions on the amount of intraspecific diversity in traits. This suggests that while urban environments may select for different trait values than non-urban areas, the strength of environmental filtering is similar across the urbanization gradient.
... Research indicates that the impact of these hot and arid air masses is responsible for extremely high temperatures, severe droughts and HWs (Clinton and Gong 2013;Debbage and Shepherd 2015;Hassan, Nayak, and Lyngwa 2021). These extreme weather events can further contribute to the occurrence or intensification of natural disasters such as forest fires and infectious disease epidemics (Melkonyan 2015). ...
Increasing temperatures cause the weather to become more severe. Studying how heatwaves (HWs) impact individual heat exposure and susceptibility is vital for building climate change mitigation and adaptation measures. So, this study explores the impact of HWs on individual heat exposure and susceptibility. The assessment was based on the highly complex topographic region contribution to HWs in the Republic of Armenia (RA) using data from 16 meteorological stations for the extended warm season (May–September). We developed a regional HW catchment program to estimate the HW indices' responses to climatic change and to present them in terms of topography changes. The Mann–Kendall (MK) test was used to determine the statistical significance of the trends for 10 distinct HW indicators using linear and exponential trends along with graphical interpretations. This study reveals a large‐scale, significant increasing trend in annual maximum temperatures (T max) and observed HWs over the period 1955–2019. The rising temperature is accompanied by an increase in HW indices, particularly at low altitudes up to 1250 m above sea level (ASL), where the main population centres and national crop production are concentrated. According to our classification, the above‐mentioned areas have faced extreme and severe increases in HW intensity, covering more than 60% of the country's territory. Moreover, not only the intensity and frequency have been identified but the HW period extension as well. This extreme increase has been found in the low‐lying highly populated and intensively cultivated areas, such as in the Ararat valley. These results have implications for future climate assessments, adaptation strategies, agriculture and public health in Armenia. The development of targeted mitigation measures and adaptation strategies informed by these findings is essential for addressing the escalating challenges posed by HWs in the region.
... A significant portion of the research in this field focuses on urban areas, where growing populations and urban sprawl intensify the effects of the "Urban Heat Island" (UHI) phenomenon [17][18][19][20]. This poses not only an ecological challenge but also a public health concern, as Central Europe, among other regions, experienced yet another summer of heatwaves [21]. ...
Agricultural intensification through simplification and specialisation has homogenised diverse landscapes, reducing their heterogeneity and complexity. While the negative impact of large, simplified fields on biodiversity is well-documented, the role of landscape structure in mitigating and stabilising climate is becoming increasingly important. Despite considerable knowledge of landscape cover types, the understanding of how landscape structure influences climatic characteristics remains limited. To explore this further, we studied an area along the Czech-Austrian border, where socio-political factors have created stark contrasts in landscape structure, despite similar topography. Using Land Parcel Information System (LPIS) data, we analysed the landscape structure on both sides, and processed eight Landsat 8 and 9 OLI/TIRS scenes from the 2022 vegetation season to calculate vegetation indices (NDVI, NDMI) and microclimatic features (surface temperature, albedo, and energy fluxes). Our findings reveal significant differences between the two regions. Czech fields, with their larger, simpler structure and lower edge density, experience more extreme temperatures and fluctuating energy fluxes, while Austrian fields exhibit greater stability. These patterns are consistent across landscape classes, with Austria’s finer landscape structure providing higher stability throughout the vegetation season. In light of climate change and biodiversity conservation, these results emphasise the need to protect and restore landscape complexity to enhance resilience and environmental stability.
... In general, lower UHI intensity has been observed in cities with more complex configurations of built-up areas due to the planting of vegetation (Yue et al. 2019). Creating more discontinuous and fractal built-up areas (Debbage and Shepherd 2015;Kamarianakis et al. 2019) and more aggregated and connected green spaces (Kim et al. 2022;Lin et al. 2023) could be an effective strategy to help cities adapt to excessive heat and to mitigate its negative consequences in the urban environment (Reckien et al. 2018). ...
Urban populations are increasingly exposed to excessive heat. Heat distribution in the urban environment can be affected by several factors, including the spatial arrangement of land use/land cover (LULC) that is specific to a given city. This study applies a climate model with urban canopy parameterisation to downscale future climate projections and simulate the spatio‐temporal pattern of heat in the urban environment to better understand the effect of LULC structure on its distribution. Heat conditions are characterised by climate indices that are well representative in two mid‐sized Central European cities of Brno and Ostrava (Czech Republic). Our results show that the annual number of hot days (HOT), summer days (SUD), tropical nights (TRN) and warm nights (WAN) will increase significantly (p < 0.01) in the 21st century in both cities. The model also simulates a more intensive increase and a higher spatio‐temporal variability in all indices in Brno compared to Ostrava. In Brno, the annual number of HOT and TRN is projected to be more than 500% of the 1981–2010 reference period's value by the end of the 21st century under the RCP 8.5 scenario. To determine the causes of the differences in heat distribution, we applied LULC configuration metrics and correlation analysis using various geographical factors. The higher risk of urban heat in Brno compared to Ostrava can be attributed to a more homogenised and less fragmented LULC structure and to the more substantial role of altitude in the complex terrain of Brno. Other factors, such as the presence of impervious surfaces and vegetation, have a similar effect on the variability of the studied indices in both cities. Urban planners should consider the role of the LULC structure and the changes that can be made in a city when designing adaptation measures to mitigate the effects of urban heat.
... Research on LST highlights the significant roles of both landscape patterns [15,16], which operate at a more macro level, and vegetation characteristic indices [17], which provide a more micro-level perspective, in mitigating the adverse effects of LST. A pronounced nonlinear correlation between UHI effects and landscape morphological indices has been observed in both intra-urban and extra-urban configurations [18]. ...
Greenscaping, a key sustainable practice, helps cities combat rising temperatures and climate change. Urban parks, a pivotal greenscaping element, mitigate the urban heat island (UHI) effect. In this study, we utilized high-resolution remote sensing imagery (GF-2 and Landsat 8, 9) and in situ measurements to analyze the seasonal thermal regulation of different park types in Zhengzhou, China. We calculated vegetation characteristic indices (VCIs) and landscape patterns (LMs) and employed boosted regression tree models to explore their relative contributions to land surface temperature (LST) across different seasons. Our findings revealed that urban parks lowered temperatures by 0.65 °C, 1.41 °C, and 2.84 °C in spring, summer, and autumn, respectively, but raised them by 1.92 °C in winter. Amusement parks, comprehensive parks, large parks, and water-themed parks had significantly lower LSTs. The VCI significantly influenced LST in autumn, with trees having a stronger cooling effect than shrubs. LMs showed a more prominent effect than VCIs on LST during spring, summer, and winter. Parks with longer perimeters, larger and more dispersed green patches, higher plant species richness, higher vegetation heights, and larger canopies were associated with more efficient thermal reduction in an urban setting. The novelty of this study lies in its detailed analysis of the seasonal thermal regulation effects of different types of urban parks, providing new insights for more effective urban greenspace planning and management. Our findings assist urban managers in mitigating the urban surface heat effect through more effective urban greenspace planning, vegetation community design, and maintenance, thereby enhancing cities’ potential resilience to climate change.
... Systemic racism and historical residential segregation have led to Black communities often residing in neighborhoods with fewer resources to combat extreme heat, such as air conditioning, cooling centers, and shaded areas [35]. Additionally, Black communities frequently live in urban areas with high population density, pollution, heat-generating industries, and limited green spaces-all factors contributing to the urban heat island effect [36,37]. This phenomenon exacerbates heat exposure, which is likely to worsen, especially during heat waves. ...
Background
Climate change has led to an increase in the frequency and intensity of extreme heat events, a trend expected to continue. This poses significant health risks, particularly for vulnerable populations like children. While previous research has largely concentrated on the physical health impacts of extreme heat, less attention has been given to behavioral outcomes, such as delinquency.
Objectives
This study investigates the association between extreme heat exposure and delinquency among children, utilizing data from the Adolescent Brain Cognitive Development (ABCD) study. It also explores the potential mediating roles of neighborhood socioeconomic status (SES; measured by median home value), puberty, peer deviance, and financial difficulties.
Methods
Data from the national ABCD study were analyzed to assess the relationship between extreme heat exposure (exposure) and delinquency (outcome). Covariates included race/ethnicity, sex, and age. Mediators examined were neighborhood SES, puberty, peer deviance, and financial difficulties. Structural equation modeling (SEM) was employed for data analysis.
Results
Overall, 11,878 children entered our analysis. The analysis revealed a significant association between extreme heat exposure and higher levels of delinquency among children. Children more exposed to extreme heat were more likely to be Black, reside in lower SES neighborhoods, experience greater financial difficulties, and have more advanced puberty status. The group facing the highest heat exposure was also economically disadvantaged.
Conclusions
The findings suggest that children already disadvantaged by socio-economic factors are disproportionately affected by extreme heat, leading to increased delinquency. This highlights the need for targeted interventions to protect these vulnerable populations and address the mediators of extreme heat exposure. Future research should focus on longitudinal studies and evaluate the effectiveness of various mitigation strategies to address these disparities.
Background
Rapid urbanization has led to a series of “urban diseases” that have garnered significant social attention. Among these, the urban heat island effect has emerged as one of the most pronounced environmental concerns, presenting formidable challenges for urban planning in terms of sustainable development and environmental livability. In this process, the construction of urban parks is particularly susceptible to discrepancies between supply and demand.
Methods
In this study, urban parks with an area of more than 3hm ² in the main urban area of Wuhan were selected as research objects. Utilizing remote sensing data and urban vector data, this study applied kernel density analysis and Thiessen polygons development to assess the supply capacity of parks’ cold islands from a supply perspective, and the residents’ cold island demand level index from a demand perspective.
Results
The findings revealed that ① The spatial distribution of cold island supply and demand exhibited significant heterogeneity. High-supply units were strongly correlated with water body distribution, while high-demand units aligned closely with population density and POI density centers, displaying a “scattered overall, locally concentrated” pattern. ② A significant supply–demand mismatch in cold island effects was observed, with 19 units (accounting for approximately 40%) exhibiting insufficient supply relative to demand. These units were predominantly concentrated in areas with complex building environments, high population density, low vegetation coverage, and poor landscape connectivity.
Discussion and conclusions
Drawing on these results, the study established an interplay between supply and demand perspectives by applying the theory of locational entropy and proposed optimization strategy for urban parks in Wuhan, aiming to achieve “a match between supply and demand in cold islands” across varying equilibrium stages of the research units. Specific measures include: optimizing the scale and layout of existing parks, reserving green spaces for ecological restoration, strengthening the protection of blue-green ecological foundations, and establishing a blue-green cold island corridor network to enhance ecological connectivity. Our work extends the understanding of the cold island effect of urban parks, assisting urban planners in proposing more targeted and effective management strategy and measures to improve the urban thermal environment, thereby contributing to the creation of healthy, equitable, and sustainable cities.
Urban development driven by population growth and technological advancements has intensified urban heat islands (UHIs), contributing to environmental damage and health risks. This study explores the potential of cool pavements as a critical strategy for mitigating UHIs, focusing on reflective, evaporative, and energy-storing technologies. Over 400 reputable scientific articles were reviewed to analyze UHI causes; measurement methods, including remote sensing and laboratory techniques; and the effectiveness of various pavement solutions. Reflective pavements demonstrated a capacity to lower surface temperatures by 5–20 °C depending on reflectivity changes, while evaporative pavements reduced temperatures by 5–35 °C based on type and design. Advanced energy-storing pavements not only achieved a 3–5 °C temperature reduction but also generated renewable energy. This research provides a comprehensive classification of pavement cooling systems and evaluates their quantitative and qualitative benefits, emphasizing the transformative role of cool pavements in enhancing urban sustainability and reducing UHI effects.
There is considerable uncertainty regarding the impact of irrigation on heat stress, partly stemming from the choice of heat stress index. Moreover, existing simulations are at scales that cannot appropriately resolve population centres or clouds and thus the potential for human impacts. Using multi-year convection-permitting and urban-resolving regional climate simulations, we demonstrate that irrigation alleviates summertime heat stress across more than 1,600 urban clusters in North America. This holds true for most physiologically relevant heat stress indices. The impact of irrigation varies by climate zone, with more notable irrigation signals seen for arid urban clusters that are situated near heavily irrigated fields. Through a component attribution framework, we show that irrigation-induced changes in wet-bulb temperature, often used as a moist heat stress proxy in the geosciences, exhibit an opposite sign to the corresponding changes in wet bulb globe temperature—a more complete index for assessing both indoor and outdoor heat risk—across climate zones. In contrast, the local changes in both wet-bulb and wet bulb globe temperature due to urbanization have the same sign. Our results demonstrate a complex relationship between irrigation and heat stress, highlighting the importance of using appropriate heat stress indices when assessing the potential for population-scale human impacts.
It is well established that urban heat island UHI has a negative impact on the health and quality of life of city dwellers, particularly during heat waves. Such as a reduction in thermal comfort, an increase in heat-related illnesses and deaths, and deterioration in air quality .Outdoor public spaces play an important role in the overall quality of life. In the northeastern of Algeria, particularly in Souk-Ahras city, the majority of the population spends most of their time outdoors, in very hot conditions. The aim of this research is to assess the outdoor thermal comfort (OTC) in two public spaces in souk ahars city and to examine the role of urban trees in regulating the urban microclimate and optimizing OTC. A questionnaire survey on the sensation of thermal comfort was carried out simultaneously with in situ measurements of the following microclimatic parameters: air temperature Ta, relative humidity RH and wind speed Va during July 2022 in the two public spaces at a total of six measurement points; to calculate and compare the physiological equivalent temperature (the PET index), the mean radiant temperature Tmrt and the sky view factor SVF using Rayman 1.2 software. The results show that air temperature (Ta) is one of the most important factors influencing a person outdoor thermal comfort in the warmer seasons. Evapotranspiration and trees shading modify the thermal perceptions of humans outdoors by affecting the outdoor thermal environment through a lowering of air temperature and an increase in relative humidity.
Kentsel ısı adası etkisi (KIA), kentsel alanlardaki sıcaklıkların kırsal çevrelere göre artışıyla karakterize edilen ve çevresel kalite, insan sağlığı ve kentsel sürdürülebilirlik üzerinde önemli etkileri olan bir olgudur. Bu sistematik literatür incelemesi, dünya genelindeki farklı şehirlerde kentsel ısı adası etkisinin mekânsal ve zamansal değişimleri üzerine yapılan çalışmaları incelemeyi amaçlamaktadır. 2024 yılı içerisinde konu ile ilgili güncel ve yüksek atıf almış çalışmaların yanı sıra Temmuz 2024'e kadar Science Direct, Taylor&Francis, MDPI ve SpringerLink gibi farklı veri tabanlarında arama yapılarak çalışmalar incelenmiştir. Araştırma veri tabanları üzerinden “KIA, kentsel ısı adası, yüzey kentsel ısı adası, YKIA” anahtar kelimeleri kullanılarak mekânsal ve zamansal değişimler üzerine yapılan çalışmalar taranmıştır. Tam metinler, atıflar ve özetler değerlendirme için kullanılmıştır. Çalışmada hakemli çalışmalar incelenerek, kentsel ısı adası yoğunluğunu etkileyen ana faktörler belirlenmiştir. Ayrıca, kentsel ısı adası araştırmalarında kullanılan yöntemler, uzaktan algılama tekniklerinden saha ölçümleri ve modelleme yaklaşımlarına kadar ele alınmıştır. Bulgular, kentsel ısı adası etkilerini azaltılmasında bütüncül kentsel planlama ve yeşil altyapı uygulamalarının önemini vurgulamaktadır. Hazırlanan tabloda kaynak/referans, amaç ve hedefler, metodoloji ve son olarak çalışmaların bulgularına yer verilmiştir. Bu kapsamlı kentsel ısı adası araştırma sentezi, sürdürülebilir ve dirençli kentsel çevreler geliştirmeyi hedefleyen şehir plancıları, politika yapıcılar ve araştırmacılar için değerli bilgiler sunmaktadır.
Agricultural intensification through simplification and specialization has homogenized diverse landscapes, reducing their heterogeneity and complexity. While the negative impact of large, simplified fields on biodiversity has been well-documented, the role of landscape structure in mitigating climatic extremes and stabilizing climate is becoming increasingly important. Despite considerable knowledge of landscape cover types, understanding of how landscape structure influences climatic characteristics remains limited. To explore this further, we studied an area along the Czech–Austrian border, where socio-political factors have created stark contrasts in landscape structure, despite a similar topography. Using Land Parcel Information System (LPIS) data, we analyzed the landscape structure on both sides and processed eight Landsat 8 and 9 OLI/TIRS scenes from the 2022 vegetation season to calculate spectral indices (NDVI, NDMI) and microclimatic features (surface temperature, albedo, and energy fluxes). Our findings revealed significant differences between the two regions. Czech fields, with their larger, simpler structure and lower edge density, can amplify local climatic extremes. In contrast, the distribution of values on the Austrian side was more even, likely due to the greater diversity of cultivated crops, a more spatially diverse landscape, and a balanced spread of agricultural activities over time. In light of climate change and biodiversity conservation, these results emphasize the need to protect and restore landscape complexity to enhance resilience and environmental stability.
Residentials, commercials, and industries are urbanization indicators in many areas. Focusing on urban geometry (H/W ratio), this research was conducted. Cilacap urbanized area was chosen as the focus of the study since it became a newly developed city in southern central Java island. Not only is Cilacap the main city that connects big cities between West Java province and Yogyakarta Special Region province, but it also has national industrial objects that create a high intensity of urban development that might influence urban heating. This study investigates the urban heating in Cilacap City using urban geometry approaches in the Geographic Information System (GIS) by calculating average building height, street width, and surface towards sustainable urban planning. As expected, this study supports the urban planner in managing the urban building configuration to reduce the heat effect. There were ten street corridors to investigate. The result shows that corridor 1, corridor 2, and corridor 3 have higher UHI intensity and H/W ratio than others, corresponding to the actual street orientation.
Cities are home to more than half of the world’s population, and this figure is set to continue to rise amidst ongoing global urbanization trends. Against this backdrop, urban development is increasingly confronted with multifaceted challenges. These range from public health emergencies, exemplified by the COVID-19 global pandemic, to the environmental hazards driven by climate change, including extreme heat waves and more frequent severe storms. Confronted with these substantial risks, the urgency of devising and implementing strategies for sustainable and resilient urban development has become paramount. Given this context, the work presented in this thesis aims to advance understanding of some critical urban sustainability challenges, and to develop models, tools, and sensing systems that can support progress towards a more sustainable and resilient urban future.
Urban form significantly affects air quality, which in turn affects public health. In this study, the effects of urban form on PM 2.5 concentration levels in the central city of Urumqi in 2000, 2010 and 2020 were analyzed by using high-resolution remote sensing data through a geographically weighted regression (GWR) model that integrates four urban form indicators and four control variables. The study shows that the PM 2.5 concentration in the central urban area of Urumqi has not only declined in the last two decades, but also the distribution range is gradually narrowing, and the relative high values are mainly concentrated in Midong District, New Urban District, and Toutunhe District; Agglomeration Index (AI), Largest Patch Index (LPI), and Road Density (RD) have significant effects on PM 2.5 concentration, (Average Minimum Neighborhood Distance) ENN_MN, Population density, GDP and precipitation have all changed from negative to positive correlation with PM 2.5 concentration in the last two decades, while temperature is always positively correlated with PM 2.5 concentration. It is shown that reducing the fragmentation of the urban landscape and the complexity of the urban shape in Urumqi as well as lowering the density of the road network can help to mitigate the concentration of PM 2.5 . The results of this study are of great significance for better understanding the relationship between urban form and PM 2.5 concentration, and for more scientific urban spatial planning.
Under global warming, surface urban heat islands (SUHI) threaten human health and urban ecosystems. However, scant research focused on exploring the complex associations between urban form factors and SUHI at the county scale, compared with rich studies at the city scale. Therefore, this study simultaneously examined the nonlinear and spatial non-stationary association between SUHI and urban form factors (e.g., landscape structure, built environment, and industrial pattern) across 2321 Chinese counties. An explainable spatial machine learning method, combining the Geographically Weighted Regression, Random Forest, and Shapley Additive Explanation model, was employed to deal with nonlinearity, spatial non-stationary, and interpretability of modeling. The results indicate the remarkable spatial disparities in the relationship between urban form factors and SUHI. Landscape structure contributes the most in southern counties, while the built environment is more important in northeastern counties. The impact of building density and building height increases with the county size and becomes the main driver of urban heat in mega counties. Most urban form factors exhibit nonlinear impacts on SUHI. For example, urban contiguity significantly affects SUHI beyond a threshold of 0.93, while building density does so at 0.17. By comparison, the influence of shape complexity remains stable above a value of 7. Factors such as industrial density and diversity have a varied influence on SUHI between daytime and nighttime. The results of local explanations and nonlinear effects provide targeted regional mitigation strategies for urban heat.
This book offers a deep exploration of architectural and urban heritage, using interdisciplinary and intercultural approaches to assess how historical, social, economic and political factors have impacted heritage development and its sustainability. It sheds light on the stakes of heritage conservation, management and maintenance in today’s globalised world.
Through detailed studies of historic cities, the book explores both the tangible aspects of their built heritage (urban fabric, housing design, construction methods and materials for thermal comfort) and the intangible components of local communities (including identities, cultures, religions, values and ways of life) in diverse case studies in Egypt, France, India, Iran, Jordan, Morocco, Syria and Tunisia.
By addressing not only urban and architectural heritage but also socio-cultural, environmental and political issues—including economic challenges and climatic concerns—this book is an essential resource for scholars and researchers across fields, including architecture, civil engineering, urban planning, sociology and philosophical anthropology.
This book offers a deep exploration of architectural and urban heritage, using interdisciplinary and intercultural approaches to assess how historical, social, economic and political factors have impacted heritage development and its sustainability. It sheds light on the stakes of heritage conservation, management and maintenance in today’s globalised world.
Through detailed studies of historic cities, the book explores both the tangible aspects of their built heritage (urban fabric, housing design, construction methods and materials for thermal comfort) and the intangible components of local communities (including identities, cultures, religions, values and ways of life) in diverse case studies in Egypt, France, India, Iran, Jordan, Morocco, Syria and Tunisia.
By addressing not only urban and architectural heritage but also socio-cultural, environmental and political issues—including economic challenges and climatic concerns—this book is an essential resource for scholars and researchers across fields, including architecture, civil engineering, urban planning, sociology and philosophical anthropology.
Release of NLCD 2006 provides the first wall-to-wall land-cover change database for the conterminous United States from Landsat Thematic Mapper (TM) data. Accuracy assessment of NLCD 2006 focused on four primary products: 2001 land cover, 2006 land cover, land-cover change between 2001 and 2006, and impervious surface change between 2001 and 2006. The accuracy assessment was conducted by selecting a stratified random sample of pixels with the reference classification interpreted from multi-temporal high resolution digital imagery. The NLCD Level II (16 classes) overall accuracies for the 2001 and 2006 land cover were 79% and 78%, respectively, with Level II user's accuracies exceeding 80% for water, high density urban, all upland forest classes, shrubland, and cropland for both dates. Level I (8 classes) accuracies were 85% for NLCD 2001 and 84% for NLCD 2006. The high overall and user's accuracies for the individual dates translated into high user's accuracies for the 2001-2006 change reporting themes water gain and loss, forest loss, urban gain, and the no-change reporting themes for water, urban, forest and agriculture. The main factor limiting higher accuracies for the change reporting themes appeared to be difficulty in distinguishing the context of grass. We discuss the need for more research on land-cover change accuracy assessment Published by Elsevier Inc.
Problem: Remotely sensed land surface temperatures help exploring the surface urban heat island. Measures to mitigate the urban heat island include increasing green urban areas and altering the form of cities. Research is needed to explore the impacts of urban form on the surface urban heat island. Research strategy: Data on land surface temperatures for summer 2001 and land cover are combined with meteorological, demographic, and topographic data for European urban regions, delineated as larger urban zones. To ensure a comprehensive view, three ways of quantifying surface urban heat island are calculated and stratified for morning and evening, and climate zones. Linear models reveal the relative influence of the four factors: (1) composition (e.g., share of different land covers in the urban region), (2) configuration (e.g., spatial arrangement), (3) location (e.g., distance to coast or elevation), and (4) population. Findings: The explanatory power (i.e., adj. R-sq) of the models varies strongly among the different ways to quantify the surface urban heat island and time of day. Rather specific combinations of explanatory variables were found to be relevant in explaining the variation in the different ways of quantifying surface urban heat islands. Compact urban form increases the surface urban heat island measured in one way, but was not a significant predictor for other ways of quantification. Increasing the share of built-up area and forest both increase the surface urban heat island. More built-up areas increased the mean temperature in the region, whereas more forest unsurprisingly decreased the overall temperature. The three ways of quantifying the surface urban heat island were correlated at r<0.5, and their variation was explained by different variables implying that they carry different information about the surface urban heat island effect. Takeaway for practice: Considerable attention needs to be paid to the aims of spatial planning, because mitigating the surface urban heat island might lead to measures that are actually increasing mean temperatures.
Multi-Resolution Land Characterization 2001 (MRLC 2001) is a second-generation Federal consortium designed to create an updated pool of nation-wide Landsat 5 and 7 imagery and derive a second-generation National Land Cover Database (NLCD 2001). The objectives of this multi-layer, multi-source database are two fold: first, to provide consistent land cover for all 50 States, and second, to provide a data framework which allows flexibility in developing and applying each independent data component to a wide variety of other applications. Components in the database include the following: (1) normalized imagery for three time periods per path/row, (2) ancillary data, including a 30 m Digital Elevation Model (DEM) derived into slope, aspect and slope position, (3) perpixel estimates of percent imperviousness and percent tree canopy, (4) 29 classes of land cover data derived from the imagery, ancillary data, and derivatives, (5) classification rules, confidence estimates, and metadata from the land cover classification. This database is now being developed using a Mapping Zone approach, with 66 Zones in the continental United States and 23 Zones in Alaska. Results from three initial mapping Zones show single-pixel land cover accuracies ranging from 73 to 77 percent, imperviousness accuracies ranging from 83 to 91 percent, tree canopy accuracies ranging from 78 to 93 percent, and an estimated 50 percent increase in mapping efficiency over previous methods. The database has now entered the production phase and is being created using extensive partnering in the Federal government with planned completion by 2006.
This study examined the relationship between urban form and carbon dioxide (CO2) emissions from urban area in fifty cities in Japan. The digital maps of administrative boundary were used to clip urban regions from scenes of the satellite images. The clipped images were classified into a binary class: urban built-up and others. The sectoral data for the CO2 emissions at the municipality level in 2005 were obtained from published sources. We used two types of approaches to quantify urban forms. The first method involved landscape metrics which describe compactness and complexity of settlement patches. Second method, which we developed, quantifies the reduction rate of urban area from the city center by applying ring-shaped buffers. The results indicated that there were correlations beteen spatial indices of urban form and sectoral CO2 emissions for the residential and passenger transport sectors. The inverse relationship between the compactness index and CO2 emissions in our study suggest that less fragmented and compact cities emit less CO2 from the passenger transportation sector than the sprawled cities. Our study indicates that less complex cities lower residential per capita CO2 emissions but too dense settlements in mono-centric form may lead to greater per capita CO2 emissions. Complexity seems to have less significant for CO2 emissions in general. Our research also favors a high income, smaller population size and denser city for lower CO2 emissions.
Previous analysis of Oklahoma City (OKC), Oklahoma, temperature data indicated that urban heat islands (UHIs) frequently formed at night and the observed UHI intensity was variable (1 degrees-4 degrees C). The current study focuses on identifying meteorological phenomena that contributed to the variability of nocturnal UHI intensity in OKC during July 2003. Two episodes, one with a strong UHI signature and one with a weak signature, were studied in detail using observations along with simulations with the Weather Research and Forecasting model. Mechanical mixing associated with low-level jets (LLJs) played a critical role in moderating the nocturnal UHI intensity. During nights with weak LLJs or in the absence of LLJs, vertical mixing weakened at night and strong temperature inversions developed in the rural surface layer as a result of radiative cooling. The shallow stable boundary layer (SBL < 200 m) observed under such conditions was strongly altered inside the city because rougher and warmer surface characteristics caused vertical mixing that eroded the near-surface inversion. Accordingly, temperatures measured within the urban canopy layer at night were consistently higher than at nearby rural sites of comparable height (by similar to 3 degrees-4 degrees C). During nights with strong LLJs, however, the jets facilitated enhanced turbulent mixing in the nocturnal boundary layer. As a consequence, atmospheric stability was much weaker and urban effects played a much less prominent role in altering the SBL structure; therefore, UHI intensities were smaller (<1 degrees C) during strong LLJs. The finding that rural inversion strength can serve as an indicator for UHI intensity highlights that the structure of the nocturnal boundary layer is important for UHI assessments.
Multi-Resolution Land Characterization 2001 (MRLC 2001) is a second-generation Federal consortium designed to create an updated pool of nation-wide Landsat 5 and 7 imagery and derive a second-generation National Land Cover Database(NLCD 2001). The objectives of this multi-layer, multi-source database are two fold: first, to provide consistent land cover for all 50 States, and second, to provide a data framework which allows flexibility in developing and applying each independent data component to a wide variety of other applications. Components in the database include the following: (1) normalized imagery for three time periods per path/row, (2) ancillary data, including a 30 m Digital Elevation Model(DEM) derived into slope, aspect and slope position, (3) per-pixel estimates of percent imperviousness and percent tree canopy, (4) 29 classes of land cover data derived from the imagery, ancillary data, and derivatives, (5) classification rules,
confidence estimates, and metadata from the land cover classification. This database is now being developed using a Mapping Zone approach, with 66 Zones in the continental United States and 23 Zones in Alaska. Results from three initial mapping Zones show single-pixel land cover accuracies ranging from 73 to 77 percent, imperviousness accuracies ranging from 83 to 91 percent, tree canopy accuracies ranging from 78 to 93 percent, and an estimated 50 percent increase in mapping efficiency over previous methods. The database has now entered the production phase and is being created using extensive partnering in the Federal government with planned completion by 2006.
The study aims to find the effects of population density on the intensity of the urban heat island through a case study done on the city of Kuala Lumpur, Malaysia. Two methodologies combined to study the urban heat island of the city; Weather Station Networks Method and Traverses Survey Method. The study used the Geographic Information System (GIS) technology to establish the colored contour maps of the urban heat island of the city for seven different days of a week, from the 20th of December 2004 to the 26th of the same month. The study shows that, there is an increase in the intensity of the urban heat island of the city of Kuala Lumpur since last similar studies done in 1985(Sham Sani 1990/1991). Accordingly, the increase in the intensity of the urban heat island of the city is 1.5 o C. On the other hand, there is a remarkable increase in the population density of the city since 1980 to 2004. The population density of the city has increased from 671 person/km2 in 1980 to 6429 person/ km2 in 2004. The study shows that, the intensity of the urban heat island of the city is proportional to population density of the city. Therefore the study concludes that, as the population density of the city increases, the intensity of the urban heat island of the city increases.
The structure of urban environments is known to alter local climate, in part due to changes in land cover. A growing subset of research focuses specifically on the UHI in terms of land surface temperature by using data from remote sensing platforms. Past research has established a clear relationship between land surface temperature and the proportional area of land covers, but less research has specifically examined the effects of the spatial patterns of these covers. This research considers the rapidly growing City of Phoenix, Arizona in the United States. To better understand how landscape structure affects local climate, we explored the relationship between land surface temperature and spatial pattern for three different land uses: mesic residential, xeric residential, and industrial/commercial. We used high-resolution (2.4 m) land cover data and an ASTER temperature product to examine 90 randomly selected sample sites of 240 square-meters. We (1) quantify several landscape-level and class-level landscape metrics for the sample sites, (2) measure the Pearson correlation coefficients between land surface temperature and each landscape metric, (3) conduct an analysis of variance among the three land uses, and (4) model the determinants of land surface temperature using ordinary least squares linear regression. The Pearson’s correlation coefficients reveal significant relationships between several measures of spatial configuration and LST, but these relationships differ among the land uses. The ANOVA confirmed that mean land surface temperature and spatial patterns differed among the three land uses. Although a relationship was apparent between surface temperatures and spatial pattern, the results of the linear regression indicate that proportional land cover of grass and impervious surfaces alone best explains temperature in mesic residential areas. In contrast, temperatures in industrial/commercial areas are explained by changes in the configuration of grass and impervious surfaces.
In this paper we investigate the regional variations in the fragmentation of urban landcover among 86 metropolitan areas and 19 megapolitan areas in the United States. Urban fragmentation was evaluated using nine spatial metrics that collectively quantified the continuity and shape complexity of urban landcover. Spatial metrics were calculated for each metropolitan and megapolitan area using a high urban threshold containing the urban core and surrounding suburbs, and a low urban threshold that further encompassed the outer exurban fringe. A principal component analysis was used to collapse the nine spatial metrics into two components of urban form: “shape complexity,” which describes the porosity of the urban fabric, and urban “continuity,” which represents the aggregation of urban patches or pixels. Urban “continuity,” and seven of nine spatial metrics, varied significantly by U.S. census region. A hot-spot analysis further revealed a high degree of spatial autocorrelation, with metropolitan areas in the Northeast and South regions generally exhibiting a more fragmented urban landscape than those in the Midwest or West regions. Relative to metropolitan areas, megapolitan areas exhibited more complex and fragmented patterns of urban land cover, presumably due to the high level of inter- and intra-urban polycentricism at this broader scale.
In this article we explore the relationships between urban form and air pollution among 86 U.S. metropolitan areas. Urban form was quantified using preexisting sprawl indexes and spatial metrics applied to remotely sensed land cover data. Air pollution data included the nonpoint source emission of the ozone (O3) precursors nitrogen oxides (NOx) and volatile organic compounds (VOCs), the concentration of O3, the concentration and nonpoint source emission of fine particulate matter (PM2.5), and the emission of carbon dioxide (CO2) from on-road sources. Metropolitan areas that exhibited higher levels of urban sprawl, or sprawl-like urban morphologies, generally exhibited higher concentrations and emissions of air pollution and CO2 when controlling for population, land area, and climate.
This paper reports on the canopy layer urban heat island (UHI) and human comfort in a range of small to large cities and villages in the Netherlands. To date, this subject has not been substantially studied in the Netherlands, since it has a relatively mild oceanic (Cfb) climate and impact was assumed to be minor. To fill this knowledge gap, this paper reports on observations of a selected network of reliable hobby meteorologists, including several in The Hague and Rotterdam. A number of alternative measures were also used to quantify UHI, i.e., the generalized extreme value distribution and return periods of UHI and adverse human comfort; its uncertainties were estimated by the statistical method of bootstrapping. It appeared essential to distinguish observations made at roof level from those made within the urban canyon, since the latter related more closely to exposure at pedestrian level and to urban canyon properties in their close neighborhood. The results show that most Dutch cities experience a substantial UHI, i.e., a mean daily maximum UHI of 2.3 K and a 95 percentile of 5.3 K, and that all cities experience a shadow effect in the morning when cities remain cooler than the rural surroundings. Also, an evident relation between the median of the daily maximum UHI and its 95 percentile was discovered. Furthermore, the 95 percentile of the UHI appears well correlated with population density. In addition, we find a significant decrease of UHI and the percentage of surface area covered by green vegetation, but the relation with open water remains unclear.
Using a micro-scale urban simulation program, we examined the sensitivity of air temperature and mean radiant temperature (MRT) of built-up urban cores to urban-area geometry (the density of buildings), thermal properties of human-made surfaces (albedo) and green cover (street trees), in 2 warm-climate cities: Pettah, Colombo (Sri Lanka) and downtown Phoenix, Arizona (USA). Air temperature and MRT are indicative of human thermal comfort, and their rural/urban gradients signify the urban heat island (UHI) effect. Although high albedo values lead to low daytime temperatures in both cities, the best thermal comfort, quantified by both the air temperature and MRT, was found in high-density development. Thus, density enhancement is a viable UHI mitigation option in built-up areas of warm climate cities. Manipulation of thermal properties is an alternative strategy, but the practical utility of high albedo surfaces is questionable. Additionally, some UHI mitigation options are more likely to bring improvements in MRT than in air temperature. Urban designers should use mitigation options that are based on human comfort, which is determined by both MRT and air temperature, rather than simply attempting to control air temperature alone.
Two Long-Term Ecological Research (LTER) sites now include urban areas (Baltimore, Maryland and Phoenix, Arizona). A goal of LTER in these cities is to blend physical and social science investigations to better understand urban ecological change. Research monitoring programs are underway to investigate the effects of urbanization on ecosystems. Climate changes in these urban areas reflect the expanding population and associated land surface modifications. Long-term urban climate effects are detectable from an analysis of the GHCN (Global Historical Climate Network) database and a comparison of urban versus rural temperature changes with decadal population data. The relation of the urban versus rural minimum temperatures (Delta Tmin(u-r)) to population changes is pronounced and non-linear over time for both cities. The Delta Tmax(u-r) data show no well-defined temporal trends.
The paper demonstrates the relationship existing between the size of a village, town or city (as measured by its population), and the magnitude of the urban heat island it produces. This is accomplished by analyzing data gathered by automobile traverses in 10 settlements on the St. Lawrence Lowland, whose populations range from 1000 to 2 million inhabitants. The locations of these settlements effectively eliminate all non-urban climatic influences. The results are compared with previously published data.The analysis shows the heat island intensity under cloudless skies to be related to the inverse of the regional windspeed, and the logarithm of the population. A simple model is derived which incorporates these controls. In agreement with an extension of Summers' model the heat island appears to be approximately proportional to the fourth root of the population. With calm and clear conditions the relation is shown to hold remarkably well for North American settlements, and in a slightly modified form, for European towns and cities.
Cities 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.
The literature on urban sprawl confuses causes, consequences, and conditions. This article presents a conceptual definition of sprawl based on eight distinct dimensions of land use patterns: density, continuity, concentration, clustering, centrality, nuclearity, mixed uses, and proximity. Sprawl is defined as a condition of land use that is repre- sented by low values on one or more of these dimensions. Each dimension is operationally defined and tested in 13 urbanized areas. Results for six dimensions are reported for each area, and an initial comparison of the extent of sprawl in the 13 areas is provided. The test confirms the utility of the approach and suggests that a clearer conceptual and operational definition can facilitate research on the causes and consequences of sprawl.
A new index of calculating the intensity of urban heat island effects (UHI) for a city using satellite skin temperature and land cover observations is recommended. UHI, the temperature difference between urban and rural regions, is traditionally identified from the 2-m surface air temperatures (i.e., the screen-level temperature T 2m) measured at a pair of weather stations sited in urban and rural locations. However, such screen-level UHI is affected by the location, distance, and geographic conditions of the pair of weather stations. For example, choosing a different pair of rural and city sites leads to a different UHI intensity for the same city, due to the high heterogeneity of the urban surface temperature. To avoid such uncertainty, satellite-observed surface skin temperature measurements (i.e., skin level temperature T skin) is recommended to re-cord UHI, known as skin-level UHI or UHI skin . This new index has advantages of high spatial resolution and aerial coverage to better record UHI intensity than T 2m . An assessment of skin-level UHI from 10 yr of the National Aeronautics and Space Administration (NASA)'s Moderate Resolution Imaging Spectroradi-ometer (MODIS) observations reveals that skin-level UHI has a strong UHI signal during the day and at night. In addition, there are significant diurnal and seasonal variations in skin-level UHI. Furthermore, the skin-level UHI is stronger during the day and summer (July) than during nighttime and winter. This new index is important for more uniformly assessing UHIs over cities around the globe. Nevertheless, whether the seasonality and diurnal variations revealed in this work using skin-level UHI index are valid over desert cities, such as Phoenix, Arizona, need to be examined.
This article explores the use of nighttime satellite imagery for mapping urban and peri-urban areas of Australia. A population-weighted measure of urban sprawl is used to characterize relative levels of sprawl for Australia's urban areas. In addition, the expansive areas of low light surrounding most major metropolitan areas are used to map the urban–bush interface of exurban land use. Our findings suggest that 82 percent of the Australian population lives in urban areas, 15 percent live in peri-urban or exurban areas, and 3 percent live in rural areas. This represents a significantly more concentrated human settlement pattern than presently exists in the United States. Este artículo explora el uso de imágenes de satélite de la noche para cartografiar áreas urbanas y peri-urbanas de Australia. Se usó una medida del desparramado urbano con peso poblacional para caracterizar los niveles relativos del desparramado en las áreas urbanas de Australia. Adicionalmente, las áreas expansivas de luz mortecina que rodean la mayoría de las principales áreas metropolitanas se usan para cartografiar la interfaz ciudad-monte, como una de las partes del uso exurbano de la tierra. Nuestros descubrimientos sugieren que el 82 por ciento de la población australiana vive en áreas urbanas, 15 por ciento vive en áreas peri-urbanas o exurbanas, y el 3 por ciento en áreas rurales. Esto representa un patrón de asentamiento humano significativamente más concentrado de lo que actualmente acontece en Estados Unidos.
The Multi-Resolution Land Characteristics (MRLC) Consortium is a group formed by the U.S. federal agencies in 1990 to purchase Landsat 5 Thematic Mapper imagery for the conterminous U.S. and to develop a National Land Cover Dataset (NLCD 1992). The NLCD 1992 was completed in 2000. In 1999, a second-generation MRLC (MRLC 2001) consortium was formed to purchase three dates of Landsat 7 Thematic Mapper Plus (and some Landsat 5) imagery for the entire United States and to coordinate the production of a comprehensive National Land Cover Database (NLCD 2001). The NLCD 2001 was completed in April 2008.The NLCD 1992 and NLCD 2001 are specifically designed to meet the needs of the U.S. federal agencies for nationally consistent satellite remote sensing and land cover database. In addition, the MRLC consortium provides the database as public domain information. This paper summarizes the philosophy and scientific and technical issues with regard to design and implementation of the NLCD 1992 and NLCD 2001. Experiences and lessons learned from the intensive efforts to develop the two national land cover datasets are documented, including project design, technical approaches, accuracy assessment strategy, and project implementation.
Progress in urban climatology over the two decades since the first publication of the International Journal of Climatology is reviewed. It is emphasized that urban climatology during this period has benefited from conceptual advances made in microclimatology and boundary-layer climatology in general. The role of scale, heterogeneity, dynamic source areas for turbulent fluxes and the complexity introduced by the roughness sublayer over the tall, rigid roughness elements of cities is described. The diversity of urban heat islands, depending on the medium sensed and the sensing technique, is explained. The review focuses on two areas within urban climatology. First, it assesses advances in the study of selected urban climatic processes relating to urban atmospheric turbulence (including surface roughness) and exchange processes for energy and water, at scales of consideration ranging from individual facets of the urban environment, through streets and city blocks to neighbourhoods. Second, it explores the literature on the urban temperature field. The state of knowledge about urban heat islands around 1980 is described and work since then is assessed in terms of similarities to and contrasts with that situation. Finally, the main advances are summarized and recommendations for urban climate work in the future are made. Copyright © 2003 Royal Meteorological Society.
The urban heat island (UHI), together with summertime heat waves, foster’s biophysical hazards such as heat stress, air pollution,
and associated public health problems. Mitigation strategies such as increased vegetative cover and higher albedo surface
materials have been proposed. Atlanta, Georgia, is often affected by extreme heat, and has recently been investigated to better
understand its heat island and related weather modifications. The objectives of this research were to (1) characterize temporal
variations in the magnitude of UHI around Metro Atlanta area, (2) identify climatological attributes of the UHI under extremely
high temperature conditions during Atlanta’s summer (June, July, and August) period, and (3) conduct theoretical numerical
simulations to quantify the first-order effects of proposed mitigation strategies. Over the period 1984–2007, the climatological
mean UHI magnitude for Atlanta-Athens and Athens-Monticello was 1.31 and 1.71°C, respectively. There were statistically significant
minimum temperature trends of 0.70°C per decade at Athens and −1.79°C per decade at Monticello while Atlanta’s minimum temperature
remained unchanged. The largest (smallest) UHI magnitudes were in spring (summer) and may be coupled to cloud-radiative cycles.
Heat waves in Atlanta occurred during 50% of the years spanning 1984–2007 and were exclusively summertime phenomena. The mean
number of heat wave events in Atlanta during a given heat wave year was 1.83. On average, Atlanta heat waves lasted 14.18days,
although there was quite a bit of variability (standard deviation of 9.89). The mean maximum temperature during Atlanta’s
heat waves was 35.85°C. The Atlanta-Athens UHI was not statistically larger during a heat wave although the Atlanta-Monticello
UHI was. Model simulations captured daytime and nocturnal UHIs under heat wave conditions. Sensitivity results suggested that
a 100% increase in Atlanta’s surface vegetation or a tripling of its albedo effectively reduced UHI surface temperature. However,
from a mitigation and technological standpoint, there is low feasibility of tripling albedo in the foreseeable future. Increased
vegetation seems to be a more likely choice for mitigating surface temperature.
This book is the first to explore the dramatic amplification of global warming underway in cities and the range of actions that individuals and governments can undertake to slow the pace of warming. A core thesis of the book is that the principal strategy currently advocated to mitigate climate change--the reduction of greenhouse gases--will not prove sufficient to measurably slow the rapid pace of warming in urban environments. Brian Stone explains the science of climate change in terms accessible to the nonscientist and with compelling anecdotes drawn from history and current events. The book is an ideal introduction to climate change and cities for students, policy makers, and anyone who wishes to gain insight into an issue critical to the future of our cities and the people who live in them.
This article presents findings from a study on residential development patterns and urban heat island formation in the Atlanta, Georgia, metropolitan region. High-resolution thermal imagery collected by the National Aeronautical and Space Administration (NASA) is used in conjunction with parcel-level tax records to examine the interaction between the design of single-family residential parcels and the emission of radiant heat energy. Results from a path analysis illustrate that lower density patterns of residential development contribute more radiant heat energy to surface heat island formation than higher density development patterns within the Atlanta region. Compact moderate-to-high-density new construction and area-based tree ordinances are recommended as policy strategies for mitigating the effects of urban development on regional climate change.
Previous studies of the influences of land use/land cover changes (LULCC) on the climate of continental areas have provided a basis for our current understanding of LULCC impacts. However, continental climates may not provide complete explanations or answer specific scientific questions for other regions, such as small tropical-maritime dominated islands. Here we present a detailed analysis of temperature change over the past century for the tropical island of Puerto Rico, using an approach that accounts for internal climate variability and spatial resolution issues and assesses the degree to which some of this change might be related to urban development. Long-term weather data, digital maps, geographic information systems (GIS) and statistical analysis were used to detect and assess differences between urban and non-urban temperature records. Strong evidence of a relationship linking temperature magnitudes to local urban development was detected, and the analysis suggests that urbanization has increased minimum, maximum and average temperatures by 0.5 °C in the warmest regions to 2 °C in the coolest regions. The results also show that the magnitude of temperature impacts depends on the contextual ecology or environment where the development has occurred. Temperature differences between urban and non-urban areas are higher in colder and wetter microclimates than in dryer warmer ones, and were less pronounced for minimum temperature than for maximum temperature. However, because the levels of impacts are based on data that had some prior adjustment intended to control for urban signals, they represent minimum estimates of the impacts of land use on temperature in Puerto Rico.
Two gridded data sets that included (1) daily mean temperatures from 2006 through 2011 and (2) satellite-derived impervious surface area, were combined for a spatial analysis of the urban heat-island effect within the Dallas-Ft. Worth Texas region. The primary advantage of using these combined datasets included the capability to designate each 1 × 1 km grid cell of available temperature data as urban or rural based on the level of impervious surface area within the grid cell. Generally, the observed differences in urban and rural temperature increased as the impervious surface area thresholds used to define an urban grid cell were increased. This result, however, was also dependent on the size of the sample area included in the analysis. As the spatial extent of the sample area increased and included a greater number of rural defined grid cells, the observed urban and rural differences in temperature also increased. A cursory comparison of the spatially gridded temperature observations with observations from climate stations suggest that the number and location of stations included in an urban heat island analysis requires consideration to assure representative samples of each (urban and rural) environment are included in the analysis.
The interactions between the structure of a city and the atmosphere have an impact on thermal comfort, air quality and building energy consumption for space heating and cooling. A mesoscale model, with a multilayer urban canopy parameterization, coupled with a simple building energy model is used to investigate such interactions by simulating 22 idealized cities in 3D with the same total population, but different population densities and vegetation fraction in the urban areas. Simulations are performed for summer and winter periods at mid latitude and for a hot dry climate. Results indicate that compact cities, with buildings with low surface-to-volume ratios, minimize the building energy consumption for space heating/cooling, but maximize the outdoor heat stress. For air quality, the optimum is for cities with intermediate population densities. The inclusion of vegetation is most of the time positive, and never detrimental, in this climate.
Introduction and Historical PerspectiveTechnical Background
Experimental ExperienceSummary Interpretation, and Examples of Diagnosing Actual Data for CollinearityAppendix 3A: The Condition Number and InvertibilityAppendix 3B: Parameterization and ScalingAppendix 3C: The Weakness of Correlation Measures in Providing Diagnostic InformationAppendix 3D: The Harm Caused by Collinearity
A better quantification of the urban heat islands (UHIs) in the Netherlands is urgently needed given the heat stress-related problems in the recent past combined with the expected temperature rise for the coming decades. Professional temperature observations in Dutch urban areas are scarce, however. Therefore, this research explores the use of observations from weather stations that were installed and maintained by weather amateurs. From a set of over 200 stations, suitable and representative data have been selected from 20 stations, using a set of objective selection criteria that are based on metadata. One year of data (January-December 2010) was considered. From these data, estimates have been obtained of the magnitude of the UHI in Dutch low-rise residential areas. A positive relation (linear model with r 2 ≈ 0.7) was derived between the summeraveraged UHI and the (neighborhood scale) population density around the observational sites. It was found that the UHI in summer is strongest in nighttime conditions and that it increases with decreasing wind speed, decreasing cloud cover, and increasing sea level air pressure. The summer-averaged UHI was;0.9°C. During nighttime in a relatively warm 1-month subperiod of the summer, the average UHI was;1.4°C. During spring and autumn, the UHI was lower than in summer; during winter, no significant UHI was observed. The agreement in results among the different stations and the accordance of the magnitude and variation of the observed UHI with those described in the literature show that automatic observations from weather amateurs can be of sufficient quality for atmospheric research, provided that detailed metadata are available.
We perform a systematic study of all cities in Europe to assess the Urban Heat Island (UHI) intensity by means of remotely sensed land surface temperature data. Defining cities as spatial clusters of urban land cover, we investigate the relationships of the UHI intensity, with the cluster size and the temperature of the surroundings. Our results show that in Europe, the UHI intensity in summer has a strong correlation with the cluster size, which can be well fitted by an empirical sigmoid model. Furthermore, we find a novel seasonality of the UHI intensity for individual clusters in the form of hysteresis-like curves. We characterize the shape and identify apparent regional patterns
Nocturnal atmospheric cooling rates were investigated in a medium sized town in Sweden. Rates were found to be very different, depending on the time of the evening/night, therefore the urban heat island (UHI) development was divided into three phases: a, differential cooling; b, transition; and c, stabilization. In phase a the UHI intensity increases by differential cooling between urban and rural areas. In phase b, after the urban heat island circulation (UHIC) starts, there is a drastic change in the rural cooling rate. The urban cooling rate is unchanged in the early evening, but about 2 h after the start of the UHIC there is a sudden increase of the cooling rate as the cool rural air reaches the city centre. The UHIC is therefore assumed to be an effective way of transporting sensible heat between the rural and urban areas. In phase c this coupling results in an equalization of the cooling rates at both the rural and the urban site from 1.5 K h−1 and 1.0 K h−1, respectively, to 0.5 K h−1. Once the UHIC is activated, the system is self-regulating since if one factor is changed some of the others have to change as well in order to preserve the balance. In phase c the advective flux is estimated to be −9±4 W m−2 and to give a central UHI potential cooling of −0.3 K h−1 of the. Copyright © 1999 Royal Meteorological Society
While the impact of urban form on transportation energy use has been studied extensively, its impact on residential energy use has not. This article presents a conceptual framework linking urban form to residential energy use via three causal pathways: electric transmission and distribution losses, energy requirements of different housing stocks, and space heating and cooling requirements associated with urban heat islands. Two of the three can be analyzed with available national data.After we control for other influences, residents of sprawling counties are more likely to live in single‐family detached houses than otherwise comparable residents of compact counties and also more likely to live in big houses. Both lead to higher residential energy use. Because of the urban heat island effect, residents of sprawling counties across the nation on average pay a small residential energy penalty relative to residents of compact counties. Implications for urban planning are explored.
In the modern era of urban climatology, much emphasis has been placed on observing and documenting heat island magnitudes in cities around the world. Urban climate literature consequently boasts a remarkable accumulation of observational heat island studies. Through time, however, methodologists have raised concerns about the authenticity of these studies, especially regarding the measurement, definition and reporting of heat island magnitudes. This paper substantiates these concerns through a systematic review and scientific critique of heat island literature from the period 1950–2007. The review uses nine criteria of experimental design and communication to critically assess methodological quality in a sample of 190 heat island studies. Results of this assessment are discouraging: the mean quality score of the sample is just 50 percent, and nearly half of all urban heat island magnitudes reported in the sample are judged to be scientifically indefensible. Two areas of universal weakness in the literature sample are controlled measurement and openness of method: one-half of the sample studies fail to sufficiently control the confounding effects of weather, relief or time on reported ‘urban’ heat island magnitudes, and three-quarters fail to communicate basic metadata regarding instrumentation and field site characteristics. A large proportion of observational heat island literature is therefore compromised by poor scientific practice. This paper concludes with recommendations for improving method and communication in heat island studies through better scrutiny of findings and more rigorous reporting of primary research. Copyright © 2010 Royal Meteorological Society
Data from urban metabolism studies from eight metropolitan regions across five continents, conducted in various years since 1965, are assembled in consistent units and compared. Together with studies of water, materials, energy, and nutrient flows from additional cities, the comparison provides insights into the changing metabolism of cities. Most cities studied exhibit increasing per capita metabolism with respect to water, wastewater, energy, and materials, although one city showed increasing efficiency for energy and water over the 1990s. Changes in solid waste streams and air pollutant emissions are mixed.
The review also identifies metabolic processes that threaten the sustainability of cities. These include altered ground water levels, exhaustion of local materials, accumulation of toxic materials, summer heat islands, and irregular accumulation of nutrients. Beyond concerns over the sheer magnitudes of resource flows into cities, an understanding of these accumulation or storage processes in the urban metabolism is critical. Growth , which is inherently part of metabolism, causes changes in water stored in urban aquifers, materials in the building stock, heat stored in the urban canopy layer, and potentially useful nutrients in urban waste dumps.
Practical reasons exist for understanding urban metabolism. The vitality of cities depends on spatial relationships with surrounding hinterlands and global resource webs. Increasing metabolism implies greater loss of farmland, forests, and species diversity; plus more traffic and more pollution. Urban policy makers should consider to what extent their nearest resources are close to exhaustion and, if necessary, appropriate strategies to slow exploitation. It is apparent from this review that metabolism data have been established for only a few cities worldwide, and interpretation issues exist due to lack of common conventions. Further urban metabolism studies are required.
Horizontal and vertical sampling of the atmosphere has provided new information on the form of Montreal's urban heat island. The horizontal pattern under clear skies with light winds shows a major heat island, with marked gradients at the periphery, and a multicellular inner core. Retarded urban cooling rates in the evening yield a maximum heat-island intensity around midnight. Combined horizontal and vertical temperature surveys show that under conditions of strong rural stability, the lowest layers of the urban atmosphere become progressively modified as air moves toward the centre of the city. The change in the form of the potential temperature profile is in good agreement with Summers' internal boundary-layer hypothesis. In Montreal differing heights of heat and SO2 emission appear to produce more than one internal layer. SO2 observations, and heat input calculations reveal two major emission sources in Montreal; one associated with an industrial complex, and the other with the downtown core.
A three-dimensional, non-hydrostatic, high-resolution numerical model was used toanalyse urban heat-island (UHI) intensity in an idealised but realistic configuration.The urban area was 20 km square and lay on flat land at about latitude 50° Nin a maritime climate. In the model the urban area was represented by anomalies ofalbedo, anthropogenic heat flux, emissivity, roughness length, sky-view factor (SVF),surface resistance to evaporation (SRE) and thermal inertia. A control simulationincluded all these factors and the resultant UHI structure, energetics and intensitywere validated against observations. The results also compared favourably withearlier simulations.
A series of experiments was conducted in which successively one of the anomaliesthat represented the urban area was omitted from the control simulation so as toprovide the basis for an assessment of its effect. In daytime the individual effectsdue to albedo, anthropogenic heat, emissivity, SVF and thermal inertia ranged from0.2 to 0.8 °C. In common with albedo, anthropogenic heat, emissivity andSVF, the SRE aided the formation of a UHI; it was also the most important factorin increasing its intensity. The roughness length had the opposite effect. At nightemissivity, roughness length, SVF and SRE had effects ranging from 0.3 to0.75 °C, but the largest effect (2 °C) was due to the anthropogenicheat. These results showed a difference in the causes of daytime and nighttime UHIs.In daytime the roughness length and SRE were the most important factors affectingUHI intensity; at night the anthropogenic heat was the most important. The simulationssuggested that the size of the urban area had a minimal effect on UHI intensity.
Variations in urban surface characteristics are known to alter the local climate through modification of land surface processes that influence the surface energy balance and boundary layer and lead to distinct urban climates. In Melbourne, Australia, urban densities are planned to increase under a new strategic urban plan. Using the eddy covariance technique, this study aimed to determine the impact of increasing housing density on the surface energy balance and to investigate the relationship to Melbourne's local climate. Across four sites of increasing housing density and varying land surface characteristics (three urban and one rural), it was found that the partitioning of available energy was similar at all three urban sites. Bowen ratios were consistently greater than 1 throughout the year at the urban sites (often as high as 5) and were higher than the rural site (less than 1) because of reduced evapotranspiration. The greatest difference among sites was seen in urban heat storage, which was influenced by urban canopy complexity, albedo, and thermal admittance. Resulting daily surface temperatures were therefore different among the urban sites, yet differences in above-canopy daytime air temperatures were small because of similar energy partitioning and efficient mixing. However, greater nocturnal temperatures were observed with increasing density as a result of variations in heat storage release that are in part due to urban canyon morphology. Knowledge of the surface energy balance is imperative for urban planning schemes because there is a possibility for manipulation of land surface characteristics for improved urban climates.
Adopting our ‘cool communities’ strategies of reroofing and repaying in lighter colors and planting shade trees can effect substantial energy savings, directly and indirectly. In our target city of Los Angeles, annual residential air-conditioning (A/C) bills can be reduced directly by about US70 M in indirect cooling and US1/2 B per year—is possible. Trees are most effective if they shade buildings, but the savings are significant even if they merely cool the air by evapotranspiration. In Los Angeles, avoided peak power for air conditioning can reach about 1.5 GW (more than 15% of the city's air conditioning). Generalized to the entire US, we estimate that 25 GW can be avoided with potential annual benefits of about US$5 B by the year 2015. Recent steps taken by cities in the warm half of US towards adoption of cool communities include (1) incorporation of cool roofs in the revised ASHRAE building standards S90.1 and (2) inclusion of cool surfaces and shade trees as tradeable smog-offset credits in Los Angeles. Other step underway include (1) plans by the US Environmental Protection Agency (EPA) to approve heat island mitigation measures in the state implementation plan to comply with ozone standards and (2) plans for ratings and labeling of cool surfaces.