Search Results (1,092)

Global warming and urban heat island effects negatively impact the development of urban thermal environments, making them very uncomfortable to live in. Green space plays an essential role in controlling and improving air pollution, regulating the microclimate, and enforcing compliance with public health requirements. Therefore, this study explored the relationship between green space and thermal comfort in the historical neighborhood of Dazhalan in Beijing through questionnaires, observational interviews, and numerical simulations. The current situation of the microclimate environment in the green space of the block was observed first. Then, the microclimate environment was simulated by the ENVI-met 5.6 software. The thermal comfort of the three types of space, such as enclosed space, strip space, and corner space, was also evaluated to explore the coupling relationship between different green space elements and microclimate evaluation factors. It was found that the thermal comfort PET had a positive correlation with the sky openness SVF. The green space morphology was quantitatively measured, and it was found that the thermal comfort PET had a negative correlation with the three-dimensional green quantity of green space. The paper developed managing strategies for optimizing the layout and construction mode of the green space. The ultimate goal was to rationally match the greening planting, improve the pavement of the underlying surface of the block, and optimize the design of the internal space topography. Full article

Urban Heat Islands are a major environmental and public health concern, causing temperature increase in urban areas. This study used satellite imagery and machine learning to analyze the spatial and temporal patterns of land surface temperature distribution in the Metropolitan Area of Merida (MAM), Mexico, from 2001 to 2021. The results show that land surface temperature has increased in the MAM over the study period, while the urban footprint has expanded. The study also found a high correlation ($r>$ 0.8) between changes in land surface temperature and land cover classes (urbanization/deforestation). If the current urbanization trend continues, the difference between the land surface temperature of the MAM and its surroundings is expected to reach 3.12 °C ± 1.11 °C by the year 2030. Hence, the findings of this study suggest that the Urban Heat Island effect is a growing problem in the MAM and highlight the importance of satellite imagery and machine learning for monitoring and developing mitigation strategies. Full article

This paper introduces a methodology aimed at bridging the gap between building energy simulation and urban climate modeling. A coupling method was developed through the Building Control Virtual Test Bed (BCVTB) and applied to a case study in Taipei City, Taiwan, to address the microclimate factors of street trees crucial to cooling energy consumption. The use of the Urban Weather Generator for weather file modification revealed a 0.63 °C average air temperature disparity. The coupling method emphasized the importance of accurate wind speed and convective heat transfer coefficients (CHTCs) on building surfaces in determining cooling energy. The results indicated that elevated CHTC values amplify heat exchange, with higher wind velocities playing a crucial role in heat dissipation. The presence of street trees was found to significantly reduce heat flux penetration, leading to a reduction in building surface temperatures by as much as 9.5% during hot months. The cooling energy was lowered by 16.7% in the BCVTB simulations that included trees compared to those without trees. The EnergyPlus-only simulations underestimated the cooling energy needs by approximately 9.3% during summer months. This research offers valuable insights into the complex interactions between buildings and their environments. The results highlight the importance of trees and shading in mitigating the heat island effect and improving energy-efficient urban planning. Full article

Previous research has found higher temperature trends at urban observatories. This study examines in depth the features of the urban environment, the thermal behaviour of land use and land cover, and the changes that have taken place in five urban areas of the Spanish Mediterranean. The CORINE Land Cover database was used to delimit the primary land use land cover (LULC) and its changes between 1990 and 2018. Once this had been established, land surface temperatures (LSTs) between 1985 and 2023 were retrieved from the Landsat database available on the Climate Engine website. There has been a significant advance in artificial land uses, which have become the main uses in the urban areas in Valencia and Alicante. An analysis of the primary land cover showed the greatest thermal increase in artificial surfaces, especially in the industrial, commercial, and transport units that are common on their outskirts, without exception in any urban area. The results are less clear for urban fabrics and agricultural areas due to their diversity and complexity. The density of vegetation is a key factor in the magnitude of the UHI, which is higher in the urban areas with more vegetated agriculture areas, therefore showing lower LST than both industrial units and urban fabrics. Another important conclusion is the role of breezes in limiting or eliminating the strength of the UHI. Sea breezes help to explain the monthly variation of UHIs. Both bodies of water and areas of dense tree vegetation provided the lowest LST, a fact of special interest for mitigating the effects of heat waves in increasingly large urban areas. This study also concludes the different effect of each LULC on the temperatures recorded by urban observatories and enables better decision-making when setting up weather stations for a more detailed time study of the urban heat island (UHI). Full article

Green roofs and walls play an important role in promoting biodiversity, reducing the urban heat island effect and providing ecosystem services in urban areas. However, the conditions on green walls/roofs (low nutrient and organic matter content, drought, high temperatures) are often unfavorable for plant growth. Arbuscular mycorrhizal fungi (AMF) can improve the growth and development of plants under stress conditions as they can increase nutrient and water uptake. In a 6-month pot experiment, we investigated the effect of AMF inoculation on the growth and NPK uptake of Festuca ovina L. and Trifolium medium L., which are used for green roofs and walls. Two variants of mycorrhizal inoculation were used in the experiment: a commercial mycorrhizal inoculant AM Symbivit (Symbiom Ltd., Lanskroun, Czech Republic) and a mycorrhizal inoculant collected from calcareous grassland in the Silesia region (Poland). Funneliformis mosseae was the most abundant species in the roots of F. ovina and T. medium with IM inoculum. In the CM variant, a dominance of F. mosseae was observed in the roots of F. ovina. In contrast, Archaeosporaceae sp. node 317 dominated in the roots of T. medium. Both inoculations had a positive effect on the increase in dry weight of the shoots of T. medium, but only the commercial inoculum had a positive effect on the growth of F. ovina. Both inoculations improved the P uptake by the roots and the P and K uptake into the shoots of T. medium. In addition, both inoculations improved the K uptake by the roots of F. ovina and the N, P and K uptake into the shoots. In conclusion, both AMF communities included in the inoculations had a positive effect on plant growth and nutrient uptake, but the effect depends on the plant and the mycorrhizal fungus species. Full article

Urban heat islands (UHIs) pose a significant challenge in cities worldwide, exacerbating energy use, air pollution, and health risks. This paper reviews the role of water bodies in mitigating UHI effects, which is vital for informed urban planning and climate adaptation. We analyze how water features, particularly when combined with green spaces and strategic urban design, can significantly cool urban environments. The effectiveness of water bodies in reducing temperatures is influenced by their size, shape, surrounding land use, climatic conditions, and vegetation. Empirical research and case studies indicate that larger and well-shaped water bodies, due to their extensive surface area and continuous evaporation, are more effective. Furthermore, the integration of water bodies with green spaces enhances cooling through increased evapotranspiration and shading. This review highlights the strategic placement and design of water bodies within urban landscapes as crucial for maximizing their cooling benefits. By integrating water features with other urban cooling strategies, such as tree planting and expanded greenery, cities can effectively counter UHI effects, leading to more sustainable and resilient urban environments. Full article

The present work is focused on the validation of the urban canopy scheme TERRA-URB, implemented in ICON weather forecast model. TERRA-URB is used to capture the behavior of urbanized areas as sources of heat fluxes, mainly due to anthropogenic activities that can influence temperature, humidity, and other atmospheric variables of the surrounding areas. Heat fluxes occur especially during the nighttime in large urbanized areas, characterized by poor vegetation, and are responsible for the formation of Urban Heat and Dry Island, i.e., higher temperatures and lower humidity compared to rural areas. They can be exacerbated under severe conditions, with dangerous consequences for people living in these urban areas. For these reasons, the need of accurately forecasting these phenomena is particularly felt. The present work represents one of the first attempts of using a very high resolution (about 600 m) in a Numerical Weather Prediction model. Performances of this advanced version of ICON have been investigated over a domain located in southern Italy, including the urban metropolitan area of Naples, considering a week characterized by extremely high temperatures. Results highlight that the activation of TERRA-URB scheme entails a better representation of temperature, relative humidity, and wind speed in urban areas, especially during nighttime, also allowing a proper reproduction of Urban Heat and Dry Island effects. Over rural areas, instead, no significant differences are found in model results when the urban canopy scheme is used. Full article

The Olympic Games are a sporting event and a catalyst for urban development in their host city. In this study, we utilized remote sensing and GIS techniques to examine the impact of the Olympic infrastructure on the surface temperature of urban areas. Using Landsat Series Collection 2 Tier 1 Level 2 data and cloud computing provided by Google Earth Engine (GEE), this study examines the effects of various forms of Olympic Games facility urban planning in different historical moments and location typologies, as follows: monocentric, polycentric, peripheric and clustered Olympic ring. The GEE code applies to the Olympic Games that occurred from Paris 2024 to Montreal 1976. However, this paper focuses specifically on the representative cases of Paris 2024, Tokyo 2020, Rio 2016, Beijing 2008, Sydney 2000, Barcelona 1992, Seoul 1988, and Montreal 1976. The study is not only concerned with obtaining absolute land surface temperatures (LST), but rather the relative influence of mega-event infrastructures on mitigating or increasing the urban heat. As such, the locally normalized land surface temperature (NLST) was utilized for this purpose. In some cities (Paris, Tokyo, Beijing, and Barcelona), it has been determined that Olympic planning has resulted in the development of green spaces, creating “green spots” that contribute to lower-than-average temperatures. However, it should be noted that there is a significant variation in temperature within intensely built-up areas, such as Olympic villages and the surrounding areas of the Olympic stadium, which can become “hotspots.” Therefore, it is important to acknowledge that different planning typologies of Olympic infrastructure can have varying impacts on city heat islands, with the polycentric and clustered Olympic ring typologies displaying a mitigating effect. This research contributes to a cloud computing method that can be updated for future Olympic Games or adapted for other mega-events and utilizes a widely available remote sensing data source to study a specific urban planning context. Full article

Optimizing urban spatial morphology is one of the most effective methods for improving the urban thermal environment. Some studies have used the local climate zones (LCZ) classification system to examine the relationship between urban spatial morphology and Surface Urban Heat Islands (SUHIs). However, these studies often rely on single-time-point data, failing to consider the changes in urban space and the time-series LCZ mapping relationships. This study utilized remote sensing data from Landsat 5, 7, and 8–9 to retrieve land surface temperatures in Changsha from 2005 to 2020 using the Mono-Window Algorithm. The spatial-temporal evolution of the LCZ and the Surface Urban Heat Island Intensity (SUHII) was then examined and analyzed. This study aims to (1) propose a localized, long-time LCZ mapping method, (2) investigate the spatial-temporal relationship between the LCZ and the SUHII, and (3) develop a more convenient SUHI assessment method for urban planning and design. The results showed that the spatial-temporal evolution of the LCZ reflects the sequence of urban expansion. In terms of quantity, the number of built-type LCZs maintaining their original types is low, with each undergoing at least one type change. The open LCZs increased the most, followed by the sparse and the composite LCZs. Spatially, the LCZs experience reverse transitions due to urban expansion and quality improvements in central urban areas. Seasonal changes in the LCZ types and the SUHI vary, with differences not only among the LCZ types but also in building heights within the same type. The relative importance of the LCZ parameters also differs between seasons. The SUHI model constructed using Boosted Regression Trees (BRT) demonstrated high predictive accuracy, with R² values of 0.911 for summer and 0.777 for winter. In practical case validation, the model explained 97.86% of the data for summer and 96.77% for winter. This study provides evidence-based planning recommendations to mitigate urban heat and create a comfortable built environment. Full article

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. Full article

Rapid urbanization and land-use changes may affect the intensity of urban heat islands (UHIs). However, research on the eastern Chinese city of Yangzhou is lacking. Using land cover data and the InVest Urban Cooling model, this study evaluated the spatiotemporal heterogeneity of the UHI effect from 1990 to 2020 and its socioecological drivers in Yangzhou City. Landscape pattern indices such as patch area (CA), percentage of landscape (PLAND), number of patches, patch density, and aggregation index were created using Fragstats 4.2 software. Several social indicators, such as gross domestic product (GDP), night-light index, and population density, were considered to explore their correlation with UHI indicators. During the past three decades, rapid urbanization in Yangzhou has intensified the UHI effect, with the cooling capacity (cc park) and heat mitigation index (HMI) decreasing by ~9.6%; however, the mixed air temperature (T air) has increased by 0.14 °C. The main heat island areas are concentrated in southern Yangzhou, including the Hanjiang and Guangling districts, and have expanded over time. T air was positively correlated with GDP, night-light index, and population density. Moreover, for the impervious land use type, cc park and HMI were negatively correlated with CA and PLAND (p < 0.01). This study contributes to a deeper understanding of the dynamics of UHIs and provides valuable insights for policymakers, urban planners, and researchers striving to create sustainable and climate-resilient cities in Yangzhou. Full article

In the 21st century, the rapid urbanization process has led to increasingly severe urban heat island effects and other urban thermal environment issues, posing significant challenges to urban planning and environmental management. This study focuses on Zhengzhou, China, utilizing Landsat remote sensing imagery data from five key years between 2000 and 2020. By applying atmospheric correction methods, we accurately retrieved the land surface temperature (LST). The study employed a gravity center migration model to track the spatial changes of heat island patches and used the geographical detector method to quantitatively analyze the combined impact of surface characteristics, meteorological conditions, and socio-economic factors on the urban heat island effect. Results show that the LST in Zhengzhou exhibits a fluctuating growth trend, closely related to the expansion of built-up areas and urban planning. High-temperature zones are mainly concentrated in built-up areas, while low-temperature zones are primarily found in areas covered by water bodies and vegetation. Notably, the Normalized Difference Built-up Index (NDBI) and the Normalized Difference Vegetation Index (NDVI) are the two most significant factors influencing the spatial distribution of land surface temperature, with explanatory power reaching 42.7% and 41.3%, respectively. As urban development enters a stable stage, government environmental management measures have played a positive role in mitigating the urban heat island effect. This study not only provides a scientific basis for understanding the spatiotemporal changes in land surface temperature in Zhengzhou but also offers new technical support for urban planning and management, helping to alleviate the urban heat island effect and improve the living environment quality for urban residents. Full article

The urban heat island (UHI) effect, where the temperature in an urban area is higher than in the surrounding rural areas, is becoming a major concern. The concept of a Local Climate Zone (LCZ) system was devised to provide an objective framework for UHI research, which allows for a microscale definition of the UHI effect within urban areas by considering ‘urban’ and ‘rural’ as a continuum versus a dichotomy. However, most LCZ types are classified only by surface structure and coverings, which seem irrelevant to climatological and microscale concepts. In addition, microclimate is influenced by urban metabolism related to human activities as well as structural effects, but the LCZ-classification system does not incorporate these functional concepts. Therefore, this study proposes a novel urban-classification system that addresses the limitations of the LCZ concept by quantifying structural and functional elements of the city at the pedestrian level using S-DoT sensors and semantic segmentation techniques. This study holds significance as it suggests a New-LCZ (N-LCZ) system to support the classification framework of highly valid urban types and follow-up studies related to the UHI. Moreover, the N-LCZ offers a regional urban-planning strategy for sustainable development through a more valid classification system. Full article

Urban agglomerations significantly alter the regional thermal environment. It is urgent to investigate the evolution and influence mechanisms of urban agglomeration heat island intensity from a regional perspective. This study is supported by Google Earth Engine long-term MODIS data series. On the basis of estimating surface urban heat island intensity (SUHI) in the Yangtze River Delta urban agglomeration from 2001 to 2020 based on the suburban temperature difference method, the causes of heat islands in the urban agglomeration were analyzed by using geographical detector analysis. Additionally, the heat island proportion (PHI) and SUHI indicators were used to compare and analyze the changing characteristics of the urban heat island effect of ten representative cities. The research reveals the following: (1) The average SUHI of the study area increased from 0.11 °C in 2001 to 0.29 °C in 2020, with an average annual increase rate of 0.009 °C. (2) According to the results of the geographical detector analysis, SUHI was influenced by several driving factors exhibiting obvious seasonal variations. (3) SUHI difference between cities is significant in the summer (1.52 °C), but smallest in the winter; the PHI difference between cities is larger in the autumn (46.7%), while it is smaller in the summer. The research findings aim to effectively serve the formulation of collaborative development plans for the Yangtze River Delta urban agglomeration. Full article

Governments across the world are facing challenges in urgently responding to the adverse impacts of climate change. Australian cities have been proactively working on various climate action plans. Despite this, the Climate Action Tracker rates Australia’s climate net zero targets, policies, and climate finance as “Insufficient”, highlighting the urgent need for substantial improvements to align Australia’s climate policies and commitments towards the Paris Agreement. This study explores the readiness of Australian cities towards climate change mitigation, with a focus on Sydney. It identifies prioritized cooling measures and proactive local governments in Great Metropolitan Sydney, through an analysis of official documents and policy statements. Interviews were conducted with local governments to gain insights into implementation processes, perceived effectiveness, challenges, and opportunities related to heat mitigation initiatives. The results reveal efforts to amend local environmental and development control plans to mitigate the urban heat island effect and create cooler, more comfortable built environments. However, challenges exist, including limited authority of local governments in urban planning, as national and state governments set stringent codes and regulations for heat mitigation. Financial constraints pose challenges, particularly in maintaining and monitoring strategic plans during their implementation stage, leading to the potential removal of sustainability measures from designs. Full article