Search Results (456)

Rapid urbanization has significantly altered urban landscape composition and configuration, making it a key driver exacerbating the urban heat island (UHI) effect. As a rapidly expanding inland city in Central China, Zhengzhou is highly sensitive to changes in landscape composition and spatial configuration. Therefore, clarifying the nonlinear relationship between landscape patterns and the urban thermal environment is of great significance for sustainable urban planning and thermal environment regulation. Taking the main urban area of Zhengzhou as the study area, this paper retrieves land surface temperature (LST) using the radiative transfer equation method based on Landsat 8 remote sensing images from August 2015 to August 2024, and constructs the surface urban heat island intensity (SUHII) index. By integrating multi-dimensional landscape pattern indices, the XGBoost machine learning model, and the SHAP interpretability method, this study systematically analyzes the nonlinear response mechanisms of landscape composition and configuration to SUHII, key regulatory thresholds, and their changes between 2015 and 2024. The results show that: (1) The SUHII in Zhengzhou was substantially higher in 2024 than in 2015. The area proportions of strong and extremely strong heat islands were higher in 2024 (26.16% and 2.34%) than in 2015 (2.22% and 0.12%), and the thermal environment differed between 2015 and 2024, shifting from a localized patch pattern to a more continuously expanding pattern. (2) Landscape area-related indices are the key factors. The areas of green space and water bodies, along with the landscape diversity index, show significant negative correlations, while built-up area and aggregation index show significant positive correlations. (3) SHAP feature importance indicates that water body area is the primary cooling factor, whereas built-up area is the primary warming factor, jointly dominating the spatial pattern of the thermal environment in Zhengzhou. (4) Landscape composition and configuration exhibit significant nonlinear responses to SUHII with region-specific thresholds, and these thresholds were higher/lower in 2024 than in 2015, suggesting a possible association with urban expansion. Specifically, stable cooling effects occurred when the water body area exceeded 3.5 km² in 2015, with the threshold rising to 4.2 km² in 2024. The warming threshold for built-up area decreased from 18.8 km² to 8.5 km², suggesting a higher sensitivity of the thermal environment to built-up area expansion in 2024 compared to 2015, characterized by a regulation pattern of “dominant scale effect and weakened configuration effect”. This study identifies thresholds specific to Zhengzhou’s main urban area at two time points (2015 and 2024), providing quantitative support and scientific basis for blue–green space optimization, precise heat island mitigation, and territorial spatial planning in Zhengzhou. These findings are based on a comparison of two time points (2015 and 2024) and do not directly capture continuous temporal dynamics. Full article

Against the backdrop of rapid urbanization and climate warming, the urban heat island (UHI) effect has severely affected ecological security and public health. Existing studies have often focused on single-city analyses or large-sample averages, with insufficient attention to the nonlinear driving mechanisms of UHI under different hydrothermal contexts. This study selects Wuhan and Xi’an as representative cities, constructing an explainable machine learning framework to interpret and compare UHI intensity across feature importance, nonlinear responses, factor interactions, and spatial differentiation. The results show that, in Wuhan, the top five factors contribute 62.4%, reflecting a composite dominance of ecology, spatial morphology, location, and human activities. In Xi’an, the top five factors contribute 72.0%, indicating a more concentrated dominant structure. Nonlinear responses reveal that key factors like NDVI have distinct effect thresholds and mechanisms in the two cities. Spatially, Wuhan displays a continuous gradient pattern characterized by center-promoting and peripheral-suppressing effects, whereas Xi’an presents a block-like mosaic structure composed of multiple juxtaposed districts. These differences suggest that UHI mitigation should move beyond a uniform control model and instead adopt climate-sensitive strategies that account for the dominant factor combinations, response thresholds, and spatial organization of each city. The proposed framework and findings provide scientific support for understanding UHI mechanisms under different hydrothermal contexts and offer targeted implications for thermal environment regulation and spatial planning in cities with similar climatic and environmental characteristics. Full article

The urban heat island (UHI) effect has become a prominent ecological and energy challenge amid rapid urbanization. This study comprehensively examined the spatiotemporal dynamics of UHI intensity in built-up areas across 216 Chinese cities spanning five climatic zones from 2000 to 2020 and quantified UHI-triggered energy consumption, as well as revealing its driving mechanisms. The results showed a significant increasing trend in UHI intensity across China’s urban built-up areas during summer days, summer nights, and winter nights from 2000 to 2020, with corresponding annual growth rates of 10.23, 5.61, and 5.08 km²·°C·a⁻¹, respectively. However, winter daytime UHI intensity declined dramatically from 4.72 °C in 2000 to −10.21 °C in 2020, which can be attributed to the reduction in socioeconomic activities during the COVID-19 period. UHI intensity intensified significantly across all climate zones, with the largest increases observed in the middle temperate zone and warm temperate zone, reaching 127.23 km²·°C and 116.04 km²·°C, respectively. Spatially, 39.8% of the 216 cities exhibited a significant increasing trend in UHI intensity, while only 2.8% showed a decreasing trend. After 2005, the contribution of large cities to UHI intensity continued to rise, reaching 54% in 2020. This study estimated UHI-induced energy consumption in terms of standard coal equivalent, with the northern and middle subtropical zones jointly accounting for over 61.9% of the annual average consumption. Regression results confirmed that impervious surface expansion served as the dominant positive driver of UHI, while vegetation coverage exerted a strong cooling effect. These findings can facilitate the formulation of region-specific UHI mitigation and energy conservation policies for cities under different climatic conditions and at diverse development scales. Mechanistic analysis further revealed that variations in impervious surface area dominated the rise in UHI intensity, whereas changes in the normalized difference vegetation index exerted a significant mitigating effect. These findings provide a solid scientific basis for targeted UHI mitigation and energy-saving management strategies for cities across different climate zones and urban scales. Full article

The rapid development of high-density cities has triggered severe ecological challenges, including habitat fragmentation, urban heat island (UHI) effects, and conflicting demands for public recreation. Traditional ecological networks (ENs) often focus only on “source” landscapes while neglecting degraded “sink” areas. This bias limits the ability of planners to resolve complex spatial conflicts. Therefore, the primary aim of this study is to develop a robust spatial planning framework that mitigates urban ecological conflicts and enhances regional resilience. To achieve this, we constructed a composite ecological network (CEN) for the high-density city of Guangzhou that harmonizes bird habitat conservation, thermal regulation, and cultural recreation. We combined the MaxEnt model, morphological spatial pattern analysis (MSPA), and circuit theory to identify functional “sources” and “sinks” across these three dimensions. Next, using complex network theory, we optimized the CEN and evaluated its structural robustness using low degree addition (LDA) and low betweenness addition (LBA) strategies. The results indicate the following: (1) The CEN effectively captured the complex mosaic landscape of the city. (2) Single-objective networks displayed distinct spatial differences—the recreational network formed a dispersed web of 242 corridors, while habitat and climate networks remained highly clustered. (3) The integrated CEN generated 1137 multi-layered corridors, creating a vital green skeleton to support species dispersal, mitigate UHI effects, and improve cultural access. (4) Optimization simulations verified that the LBA strategy provided the highest stability against targeted attacks by balancing network connectivity with local aggregation. Ultimately, this framework offers a highly adaptable planning tool for dense cities, providing precise spatial guidance to overcome ecological bottlenecks and harmonize urban growth with ecosystem resilience. Full article

Rapid urbanization and climate change have severely exacerbated the urban heat island (UHI) effect in high-density subtropical megacities. Traditional linear models often fail to capture the complex, non-linear thermal responses driven by three-dimensional (3D) urban morphology and socio-ecological interactions. This study proposes a data-driven analytical framework explicitly tailored for macro/mesoscale climate-resilient urban planning to deconstruct the non-linear associations of Land Surface Temperature (LST) in Shenzhen, China. Integrating multi-source spatial data into a 500 m grid, we utilized the eXtreme Gradient Boosting (XGBoost) algorithm for high-precision LST modeling (R² = 0.7851, MAE = 1.1381 °C) and applied the SHapley Additive exPlanations (SHAP) approach for spatial interpretability. The results reveal critical non-linear thresholds: vegetation (NDVI) cooling efficiency saturates at 0.8, while impervious surfaces (ISA) transition into dominant heating drivers beyond 0.7. Notably, a synergistic effect indicates that high building volume density (BVD) significantly amplifies the marginal cooling benefits of vegetation. Furthermore, local SHAP attribution combined with K-Means clustering facilitated the delineation of four distinct thermal management zones. This framework shifts UHI mitigation from broad, uniform policies to precise, data-driven spatial diagnostics, offering actionable “one zone, one policy” strategies for sustainable architectural and climate-resilient urban planning. Full article

Cities are artificial ecosystems that suffer most from environmental issues and climate change. Urban Heat Island (UHI) effects represent an increasing challenge, especially for compact Mediterranean cities characterized by high population density and extensive impervious surfaces. This study assessed localized microclimatic conditions within the small Maltese coastal town of Isla through a 15-day summer field monitoring campaign. Air temperature, relative humidity, and wind speed were measured across urban locations characterized by different levels of vegetation coverage and thermal vulnerability. The analysis combined descriptive statistics, Mann–Whitney U testing, and Multiple Linear Regression (MLR) models. In addition, site-specific Nature-based Solutions (NbS) scenarios were proposed as context-sensitive strategies to support urban heat mitigation and climate resilience. The results highlighted distinct microclimatic responses between the sites investigated. In particular, the MLR analysis suggested that non-vegetated areas were more sensitive to short-term atmospheric variability associated with wind speed and relative humidity fluctuations. These findings suggest that urban vegetation may contribute not only to localized cooling, but also to increased microclimatic stability within compact Mediterranean urban environments. Full article

Urban heat island (UHI) mitigation is essential for improving urban sustainability by reducing heat stress, energy demand, and climate-related health risks. This study evaluates three rooftop measures—highly reflective roofs (HR), green roofs (GR), and rooftop water sprinkling (WR)—in Osaka Prefecture, Japan, using an integrated assessment framework. Temperature changes induced by each measure were simulated using the Weather Research and Forecasting (WRF) model and linked to energy consumption and health impacts through temperature sensitivity coefficients. Health impacts were quantified using disability-adjusted life years (DALYs), and all impacts were monetized for cost–benefit analysis. All measures reduced summer outdoor air temperatures, although their temporal and seasonal effects differed. HR and WR mainly produced daytime cooling, whereas GR provided stronger nighttime cooling. HR and GR increased residential energy consumption due to higher winter heating demand, while WR avoided this penalty through seasonal operation. All measures reduced office and commercial energy consumption and improved health impacts, with GR and WR producing larger benefits than HR. WR achieved the highest benefit–cost ratio, followed by GR and HR. These findings emphasize temporal characteristics, seasonal trade-offs, and spatial targeting in UHI policy. Full article

Urban areas in Mediterranean climates are increasingly affected by extreme heat, exacerbated by the Urban Heat Island (UHI) effect and the lack of climate-responsive public spaces. This study addresses the need for integrated methodologies combining empirical monitoring and simulation tools to support regenerative urban design. The objective is to evaluate the effectiveness of Nature-Based Solutions (NBSs) in improving microclimatic conditions and outdoor thermal comfort during summer heatwave periods in a vulnerable urban area in Seville (Spain). A mixed-method approach combining microclimatic monitoring and ENVI-met simulations in situ was applied. A field campaign conducted in summer 2023 was used to characterize baseline conditions and calibrate the model, which simulated both current and proposed scenarios incorporating vegetation, shading systems, permeable materials, and water features. Results from the Seville case study show significant improvements, with air temperature reductions of up to 1.6 °C (daytime) and 1.9 °C (nighttime), surface temperature decreases of up to 11 °C, and thermal comfort improvements reaching 8 °C in UTCI. Beyond environmental benefits, the intervention promotes socially regenerative public space by enhancing usability, inclusivity, and comfort. Limitations include the use of a single representative summer day and inherent simplifications of the ENVI-met model. These findings demonstrate the potential of integrated NBS strategies to mitigate urban heat and support climate-adaptive and socially responsive urban design. Full article

Amid growing concerns over global warming, ensuring the outdoor thermal comfort (OTC) of public urban spaces is crucial for creating liveable and resilient cities. This study focused on the intensification of the urban heat island (UHI) effect and the heat stress experienced by the vulnerable older population. Evidence was found through the case study in a highly vulnerable area of Porto, with a high ageing ratio. The primary aim was to assess the influence of design-based adaptation strategies on OTC using ENVI-met, with a specific focus on older adults. Thermal stress was evaluated using the Physiological Equivalent Temperature (PET) index. The analysis confirms that older adults consistently experience higher PET values (+2–5 °C) and larger areas of thermal discomfort than active-age adults. Simulations reveal that the effectiveness of adaptation measures depends on the characteristics of the urban space but enhanced green infrastructure achieves the most significant heat mitigation results. Artificial shading only provides localized thermal relief. Cool pavements contribute meaningfully by lowering surface heat storage and reducing longwave radiation. However, their impact on PET, beneficial or detrimental, depends significantly on the morphology of the outdoor space and the materials used. In the analysed street canyon, PET was higher in the central hours of the day for both age ranges, when the pavement material had a higher albedo. An effective heat mitigation needs a combination of vegetation-based strategies and climate-responsive materials to ensure comfortable and age-inclusive public spaces. This research presents an actionable methodological approach for evaluating and enhancing OTC, advocating the use of microclimate simulations in a carefully selected set of public spaces within an intervention urban area to define effective climate adaptation measures for each space. Full article

Rapid urbanization in South Asian coastal cities is systematically dismantling natural cooling infrastructure, driving unprecedented urban heat island (UHI) intensification with severe consequences for human health, energy systems, and urban livability. Despite growing research attention, comprehensive frameworks that simultaneously capture temporal UHI dynamics, machine learning-based thermal projections, and community-grounded validation remain scarce, particularly for secondary coastal cities in tropical developing regions. This study addresses these gaps by investigating UHI dynamics in Chattogram City Corporation (CCC), Bangladesh, through three integrated methodological pillars: (1) multi-temporal remote sensing analysis using Landsat 5 and 8 imagery spanning 2005–2025; (2) comparative evaluation of five machine learning algorithms (LightGBM, Random Forest, XGBoost, SVM, and MLP) for land use/land cover (LULC) classification and land surface temperature (LST) regression, with iterative scenario projections for 2029, 2033, and 2037; and (3) a structured public perception survey of 384 residents validated through participatory mapping and focus group discussions. Landsat analysis revealed dramatic LULC transformations: built-up areas expanded 88% (12,649 to 23,719 acres), while waterbodies declined 53.1% and vegetation decreased 21.9%. Mean LST increased by 9.09 °C (from 30.94 °C to 40.03 °C), with mean UHI intensity rising from 19.59 to 33.88 standardized units over two decades. LightGBM achieved optimal LULC classification (F1-weighted: 0.765) while Random Forest best predicted LST (RMSE: 1.51, R²: 0.809). Projections indicate continued thermal escalation, with mean LST reaching 43.64 °C and UHI intensity exceeding 37.41 standardized units by 2037. Persistent thermal hotspots were identified in the southwestern coastal corridor, western industrial belt, and central business district. Community survey data corroborated satellite-derived patterns, with 73.44% of respondents observing environmental degradation, yet only 22% aware of formal heat mitigation policies, and 87% supporting vegetation-based cooling interventions. This integrated framework advances urban thermal monitoring in tropical coastal cities and provides spatially targeted, community-endorsed evidence for climate-responsive urban planning. Full article

As a critical component of urban ecological infrastructure, urban forests play a pivotal role in regulating regional climate and mitigating the urban heat island (UHI) effect. However, existing studies have predominantly focused on single temporal snapshots or aggregate spatial scales, with limited attention to the seasonal dynamics of urban forest landscape patterns and a lack of systematic quantification of their nonlinear regulatory mechanisms. Empirical evidence from subtropical cities remains particularly scarce. In this study, Hangzhou was selected as the study area. Land Surface Temperature (LST) was retrieved using the Google Earth Engine (GEE) platform, and the Thermal Field Variance Index was employed to classify UHI intensity. Six representative forest landscape indices were selected to construct an evaluation framework. Pearson correlation analysis and the XGBoost model were further applied to quantify the relationships between landscape patterns and seasonal LST variations. The results reveal that: (1) LST in Hangzhou exhibits pronounced seasonal variability, following the order of summer > spring > autumn > winter. Areas without UHI effects dominate in spring, summer, and autumn, whereas the extent of strong UHI zones increases markedly in winter. (2) All landscape indices are significantly correlated with seasonal LST; forest ratio and forest largest patch index show negative correlations, while forest patch density, forest landscape shape index, number of patches, and landscape division index (DIVISION) are positively correlated. (3) The XGBoost model indicates that DIVISION consistently exhibits high contribution across all seasons, identifying it as a key determinant of LST variation. These findings provide a scientific basis for optimizing urban forest landscape configuration and developing effective UHI mitigation strategies. Full article

It is commonly accepted that vegetation plays an important role in climatic studies conducted at local, national, and international scales. The aim of this study is to examine the cooling effects of tree species in the cities and to reveal how they affect the microclimate in İzzetpaşa Neighborhood of Elazığ province of Turkiye. This study, which was conducted by purchasing ENVI-met 5.6.1 microclimate software, aimed to create the most appropriate microclimate scenarios in order to mitigate the urban heat island (UHI). Among the nine scenarios in which different tree species were used; the greatest cooling effect was obtained from the scenario where Acer platanoides L. was used. It was determined that the air temperature dropped by 0.8 °C compared to the base scenario and by 3.0 °C compared to the scenario in which a tree cover was not used. The lowest cooling effect was detected in the scenarios where Pinus sylvestris L. and Abies cilicica Carr. were used. In general, it was observed that there was no significant temperature decrease in the scenarios where coniferous trees were used. In scenarios where deciduous trees were used, more temperature decreases were detected compared to the coniferous trees. According to the winter simulation results of these scenarios, the daily average air temperature values vary between −0.6 and +0.1 °C compared to the base scenario. In the scenario where Acer platanoides L. was used, where the highest cooling effect was observed, the highest relative humidity rate and the lowest Tmrt value were determined. Evaluating the cooling effect of high vegetation on a species basis in reducing the UHI effect as a basis for planning in urban areas will constitute a key strategy in improving the UHI effect. It is envisaged that this study may provide a solution to help reduce the UHI in studies to be carried out in urban areas. Full article

Rapid urbanization and the decline of inner-city areas have led to a sharp increase in vacant houses in large cities. Cities are increasingly converting vacant land into green space to mitigate associated negative externalities. This study quantifies the urban heat island (UHI) mitigation effects of green infrastructure using meta-analysis and applies the derived relationships to predict both on-site and surrounding cooling effects for vacant land. First, we conducted a meta-analysis of published studies reporting the cooling effects of green infrastructure and derived regression equations relating green-space area to (i) cooling within the green space, (ii) cooling in the surrounding area, and (iii) the spatial extent of the cooling effect. Second, we applied these equations to two high-density areas in Sungui-dong, Nam-gu, Incheon, Republic of Korea. The results suggest that introducing a neighborhood park at Site A (7559.5 m²) would reduce air temperature by up to 2.751 °C within the park and by 1.507 °C up to 62 m beyond the park boundary. A pocket park at Site C (992.1 m²) would reduce air temperature by up to 2.269 °C within the park and by approximately 0.92 °C in the surrounding area. These findings provide quantitative evidence that green infrastructure can serve as an effective environmental intervention and support the adoption of climate-responsive urban regeneration policies. Full article

Climate change exerts growing pressure on the built environment, intensifying urban heat stress, altering microclimatic conditions, and increasing energy demand and health risks. Urban areas, characterized by dense construction and extensive soil sealing, are particularly susceptible to thermal anomalies such as Urban Heat Islands (UHIs), making thermal assessment a crucial element in adaptation and mitigation strategies. This research provides an updated and critical review of methodologies for the thermal evaluation of the built environment, with a focus on remote sensing as an emerging and integrative measurement paradigm. The study presents a comprehensive framework of detection systems, including satellite and aerial remote sensing, ground-based monitoring, and hybrid approaches, complemented by analytical and modeling techniques that combine physical and data-driven methods. A comparative assessment of open-access satellite sensors is carried out, analyzing spatial, spectral, and temporal resolutions and their relevance to urban-scale applications. The integration of remote sensing data with artificial intelligence, machine learning, and cloud-based processing is highlighted as a key advancement for improving interpretative, predictive, and decision-support capabilities. The findings indicate that such integration represents a new frontier for multiscale thermal analysis, supporting resilient urban planning, enhanced energy efficiency, and effective climate change mitigation policies. Full article

Sustainable water use behavior in households is a crucial component in facing the impacts of climate change on water conditions, especially in urban areas and their surroundings in countries like Indonesia. This study examines household water use behavior in urban and peri-urban areas of Surabaya and Sidoarjo in Indonesia by integrating environmental spatial characteristics and using psycho-social factors. This research methodology includes statistical analysis with the aim of examining the variable in relation to household water behavior and then integrating with spatial analysis using nearest neighborhood analyses and spatial overlay with land use/land cover (LULC) and Urban Heat Island (UHI) data, doing so to identify behavioral clustering patterns and assess spatial risk distribution. The results suggest that there is generally positive orientation toward sustainable household water use among respondents. Households in peri-urban areas show better water management behavior than those in urban areas. The implications of spatial risk in urban areas are higher due to poor behavior facing high environmental pressures. On the other hand, when overlaid with clusters of well-behaved respondents, the risk of water shortages decreases, supporting climate change mitigation efforts. Full article