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Urban climate studies often overlook the study of nighttime urban heat island (UHI) at high spatial resolutions, such as those provided by Landsat. Previous research has primarily focused on daytime and nighttime UHI at coarser spatial resolutions, such as those offered by MODIS. Furthermore, there is a lack of studies that compare two Landsat night images over a period to assess temporal changes, which has not been comprehensively explored. In this study, the Global Artificial Impervious Area dataset was utilized to define urban, while Landsat-5 & 8 daytime and nighttime data (1988, 2015) were employed to classify land cover and extract nighttime land surface temperature (LST). Statistically significant hotspot analysis was applied to quantify the UHI. The findings revealed a 94% increase in urban cover and a 1.8% decrease in vegetation cover between 1988 and 2015. This urban expansion contributed to an average increase of 10 °C in LST across Greater Cairo. The analysis further indicated that every 42.7 km2 increase in urban cover corresponds to a 1 °C rise in LST. Streets and industrial areas exhibited the highest LST readings, while compact buildings, especially older structures, recorded higher surface LSTs compared to open buildings with diverse architectural designs, which experienced lower LST values. Hotspot analysis identified an increase in UHI intensity, with a rise from 2.5 °C in 1988 to 2.7 °C in 2015. These findings highlight the critical need for sustainable urban planning and climate-responsive policies to mitigate the adverse effects of urbanization on thermal environments. This study provides a foundation for future research and emphasizes the importance of using high-resolution nighttime thermal imagery for UHI assessments in cities worldwide. [ABSTRACT FROM AUTHOR]

With urbanization, ozone (O3) pollution and the urban heat island (UHI) effect have become increasingly prominent. UHI can affect O3 production and its dilution and dispersion, but the underlying mechanisms remain unclear. This study investigates the spatial and temporal distribution of O3 pollution and the UHI effect, as well as the influence of UHI on O3 pollution in the Sichuan Basin. Atmospheric pollution data for O3 and NO2 from 2020 were obtained from local environmental monitoring stations, while temperature and single-layer wind field data were sourced from ERA5-Land, a high-resolution atmospheric reanalysis dataset provided by the European Centre for Medium-Range Weather Forecasts (ECMWF). The results indicate the following: (1) O3 concentrations in the Sichuan Basin exhibit distinct seasonal variations, with the highest levels in spring, followed by summer and autumn, and the lowest in winter. In terms of spatial variation, the overall distribution is highest in western Sichuan, second highest along the Sichuan River, and lowest in central Sichuan. (2) There are significant regional differences in UHII across Sichuan, with medium heat islands (78.63%) dominating western Sichuan, weak heat islands (82.74%) along the Sichuan River, and no heat island (34.79%) or weak heat islands (63.56%) in central Sichuan. Spatially, UHII is mainly distributed in a circular pattern. (3) Typical cities in the Sichuan Basin (Chengdu, Chongqing, Nanchong) show a positive correlation between UHII and O3 concentration (0.071–0.499), though with an observed temporal lag. This study demonstrates that UHI can influence O3 concentrations in two ways: first, by altering local heat balance, thereby promoting O3 production, and second, by generating local winds that contribute to the diffusion or accumulation of O3, forming distinct O3 concentration zones. [ABSTRACT FROM AUTHOR]

Rapid urbanization has altered land use and land cover to accommodate the growing population. This shift towards urbanization has resulted in the UHI effect, where the inner urban core is notably warmer than its surroundings. Existing research on UHI has primarily focused on major cities at the regional scale, leaving a gap in addressing the effect of extreme UHI zones within a city. This study bridges the gap by developing a methodology to quantify the impact of LULC change on the localized UHI zones within the urban areas, which will assist policymakers in mitigating urban heat. LULC change matrix analysis and LST retrieval were done from the Landsat 5 and 8 images acquired between 1988 and 2023. Representative study sites that intersected with the LULC conversion from water bodies and vegetation to other LULC and which showed maximum UHI were selected. Mean LST was calculated for the proximity of 1000 m around the selected areas. The developed methodology was applied to the Chennai Metropolitan Area in Tamil Nadu, India. The conversion of Pallikaranai marshland to the Perungudi dumping ground (PDG), and the green cover to the Kodungaiyur dumping ground (KDG) has led to an average increase in UHI intensity of 0.21 °C/year and 0.15 °C/year, respectively. The UHI effect is felt at the distance of 450 m from PDG and 550 m from KDG, which have shown that the life within the proximity are expected to experience the UHI effect. Therefore, it is imperative to alleviate the rising UHI around the selected areas. This developed methodology can be applied globally to select the targeted UHI zones for sustainable urban planning to mitigate urban heat. [ABSTRACT FROM AUTHOR]

This paper deals with the issue of air cooling in outdoor areas of human habitation. An analysis of air parameters during the summer season was carried out to determine the thermal comfort zone for a part of the northern platform of the local station in Rzeszow (Poland). The cooling capacity required for thermal comfort was calculated using outdoor air parameters and heat gains in the vicinity of the research object. Ten potential air-cooling systems were proposed for the outdoor zones. The systems differed in terms of cooling equipment, primary energy source, cooling medium, and recipients. They were divided into three categories: compressor, adsorption, and evaporative cooling. The electricity yield of the existing photovoltaic installation at the research facility was evaluated to identify potential synergies between the cooling demand and solar energy. An analysis assessed the energy, economic, and environmental impact of each proposed option. The best option for cooling the outdoor areas was found to be an evaporative cooling system with a PV system. Solar radiation can be effectively used for cooling outdoor zones in Poland in the summer. The optimal solution for the research facility is an evaporative cooling system based on direct evaporation combined with a photovoltaic system. The subject matter covered can be used as an effective tool for the optimal selection of outdoor air-cooling systems to ensure the thermal comfort of the occupants. [ABSTRACT FROM AUTHOR]

Undoubtedly, urbanization has improved human living conditions. However, it has also altered the natural landscape, leading to negative consequences such as increased Land Surface Temperature (LST) and Urban Heat Island (UHI) due to the expansion of Impervious Surface (IS). Much research has been conducted in other countries on the effects of changing urban landscape structures on LST and UHI formation. However, in Sri Lanka, only a few studies have been available on this topic, primarily concentrating on major cities like Colombo. Impervious Surface is absorbing high amounts of solar energy as well, which accelerates the magnitude of UHI in urbanized areas. Remote Sensing indices such as the Normalized Difference Vegetation Index (NDVI), Normalized Difference Buildup Index (NDBI), UHI, and Environmental Criticality Index (ECI) can effectively be used to quantify the intensity of the UHI phenomenon. This study aimed to investigate the effect of spatiotemporal variations in IS and Green Surface (GS) on UHI, LST, and the environmental criticality in Galle Municipal Council (MC), Sri Lanka employing multi-temporal Landsat-5 and 8 data from four different periods: 1996, 2005, 2014, and 2022. Different geospatial techniques including supervised image classification, Urban-Rural Gradient Zone (URGZ) analysis, grid-based analysis, UHI profiles, and regression analysis were used in the study. The findings revealed that Impervious Surface increased by 42.3% (7.34 km2) while Green Surface had a decline of 22.5% (3.91 km2) during the concerned period. This landscape transition led to a 2.74 C increase in mean surface temperature in the study area, along with a 9.5 C increase in the UHI index during 26 years. The results further revealed that Impervious Surface rapidly developed within 4 km (URGZ1-19) from city center, while Green Surface decreased. Newly built-up areas within the 1.5 km gradient (URGZ1-URGZ8) were more affected by increased LST. A positive correlation was identified between NDBI and LST, especially in the year 2022, with an R2 of 0.457, while NDVI and LST reported a negative R 2 of 0.257. The grid-based analysis demonstrated an increasingly positive relationship between mean LST and the fraction of Impervious Surface, highlighting the role of built-up areas in raising LST and UHI in the MC. As a result, very high environmental critical areas have been concentrated in and around high-density Impervious Surface. Thus, it can be predicted that the UHI effect and Environmental Criticality (EC) may increase further in the future. In this context, planning agencies should prioritize green urban planning strategies, such as implementing green belts and urban agriculture in the study area, particularly in and around areas with high LST and high environmental criticality. This approach may help protect the natural environment and sustainably ensure the health of the urban community. [ABSTRACT FROM AUTHOR]

Urban blue-green space cooling island effect (BGCI) is effective in improving the thermal comfort of residents. However, there is little knowledge regarding the diurnal variation of BGCIs and the influencing factors. Therefore, we selected Beijing as the study area and used ECOSTRESS LST data and the inflection–maximum perspective method to explore the diurnal variation of BGCIs. Additionally, we investigated diurnal variations in the relative influence of the characteristics of the blue-green space itself, as well as the surrounding 2D and 3D landscape metrics using boosted regression tree model. The results indicated that BGCIs displayed distinct diurnal patterns. BGCIs progressively increased from sunrise to midday, decreased thereafter to sunset, reached its peak around midday, and diminished to a relatively low level and constant intensity at night. BGCIs of water bodies exhibited a significantly higher intensity compared to vegetation during the day, particularly around midday, with a difference in mean cooling intensity (CI) of 1.06 °C and mean cooling distance (CD) of 63.27 m, while the differences were minimal at night with a difference in mean CI of 0.02 °C and mean CD of 9.64 m. The features of vegetation had a more significant impact on BGCIs during the day, particularly around midday (CI: 32.30% around midday and 13.86% at night), while the 3D metrics influenced BGCIs more at night (CI: 26.40% around midday and 35.81% at night). The features of water bodies had a greater impact during the midday (52.87% around midday and 10.46% at night), with the landscape metrics of surrounding water bodies playing a more important role at night (15.56% around midday and 38.28% at night). The effect of tree height, shape index of vegetation, and surrounding building coverage ratio of water bodies on BGCIs exhibited opposite trends around midday and at night. Optimizing the landscape surrounding blue-green spaces is more cost-effective than the blue-green spaces themselves for nighttime thermal comfort, especially in 3D urban landscapes. These findings emphasize the imperative and essentiality of exploring diurnal variations in BGCIs, providing valuable information for mitigating UHI effects. [ABSTRACT FROM AUTHOR]

This study examines the ecological and thermal impacts of urbanization in Malakand Division, Pakistan, from 2003 to 2023, focusing on the Surface Urban Heat Island (SUHI) effect and human thermal comfort (HTC). Using multi-temporal Landsat (5 and 8) imagery, Land Surface Temperature (LST) data, and the Urban Thermal Field Variance Index (UTFVI), we analyze urban expansion, land-use changes, and their thermal implications. Results show significant urban growth, with built-up areas increasing from 11,773.5 km² to 12,519.09 km², while vegetative land decreased by 7.5%. The average LST rose by 3.67°C, and UHI intensity increased from 15.96% in 2003 to 19.08% in 2023. Spatial analysis highlights higher LST and UTFVI values in urbanized and transition zones, indicating worsening thermal conditions. These findings underscore the need for sustainable urban planning to mitigate UHI effects, enhance HTC, and promote green space development. This research provides critical insights for urban planners and policymakers in Malakand Division and other rapidly urbanizing regions

Objectives The phenomenon of urban heat island (UHI) is based on the occurrence of elevated air temperature in urban areas, in relation to the surrounding urban, rural and forest areas. The aim of the study was the assessment of the UHI in Łódź in 2014–2019. Łódź is a large city with an area of 293.3 km 2 , located in the center of Poland. Material and Methods The UHI was defined as the difference of at least 1.5°C in daily minimum temperature at the point representing the commutative conditions (lower temperature) and daily minimum temperature at the point located in the city center (higher temperature). Based on data from the Weather Research and Forecasting (WRF)/CALMET models and the above criterium, the occurrence of UHI cases was analyzed. Results In summary the phenomenon of urban heat island in 2014–2019 was observed in every studied year, most often in 2018 with the highest UHI index almost 5°C, and increased over the years. The results proved that the highest UHI contrast was seen at night between 11 p.m. and 3 a.m. Conclusions The study confirms that the UHI phenomenon in Łódź is persistent and has expanded in spatial extent over the years due to urban growth. Int J Occup Med Environ Health. 2024;37(6):581–90

The Covid-19 outbreak rapidly became a global pandemic in December 2019, spreading through droplets, direct contact, and possibly airborne transmission. Southeast Asian nations like Malaysia and Indonesia experienced delayed outbreaks but saw a surge in cases. Analysing Covid-19 spatial patterns, especially concerning temperature and humidity, provides valuable insights. Utilizing remote sensing, allows studying the correlation between temperature conditions and Covid-19 outbreak patterns. This study focuses on investigating the impact of urban heat islands (UHIs) on Covid-19 outbreaks in Jakarta and Greater Kuala Lumpur, given their significant caseloads in Indonesia and Malaysia, respectively. The research integrates remote sensing, secondary data, and statistical analysis methods. Remote sensing was used to acquire land surface temperature (LST) and Normalized Difference Vegetation Index (NDVI). The analysis revealed that industrial and commercial areas were hotter than others during normal times, but during the pandemic, LST and UHI shifted from industrial to settlement areas due to large-scale social restrictions. This shift corresponded with the cessation of office, tourism, and industrial activities during lockdowns in March and July 2020 in Jakarta and Greater Kuala Lumpur, respectively. The concentration of people shifted from central business and industrial areas to residential areas during lockdowns, resulting in changes in UHI patterns. [ABSTRACT FROM AUTHOR]

Climate change significantly impacts transportation infrastructure, particularly asphalt pavements. Similarly, the heat absorption of paved surfaces, especially conventional black pavements, significantly intensifies the urban microclimate. Paved surfaces, including asphalt pavements, account for over 30% of the covered surfaces and are vulnerable to rising temperatures, which cause not only pavement distress, such as rutting and cracking, but also urban heat islands (UHI). Sustainable pavement solutions, specifically colored pavements, have been investigated for their potential to mitigate these effects. This review presents an extensive overview of current pavement technologies, emphasizing conventional asphalt's economic, environmental, and functional characteristics. A discussion of the benefits and challenges of colored pavements is also provided, including their ability to reduce UHI, enhance safety, and contribute to sustainable urban growth. This paper discusses advancements in pavement material science, the use of recycled materials, and the application of reflective coatings, providing insights into sustainable infrastructure development. Transitioning from conventional black pavements to sustainable colored alternatives is not merely a matter of material choice but a strategic transition toward resilient urban planning. Increasing demand for environmentally friendly infrastructure could prompt the construction industry to adopt colored pavements as a tool to promote environmental stewardship. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

The surface urban heat island (SUHI) is caused by a combination of variables, broadly classified as climate change, land use change, and urbanization. They have varying degrees of influence depending on their level of intensity. As a result, recognizing the primary cause is critical to resolving the issue and developing suitable policies to reduce resource waste. This study attempted to identify the underlying cause of SUHI by primarily evaluating the intensity of the surface urban heat island using primary and secondary data. Zonal Statistics, the Mann-Kendall trend test, Oke’s UHI model, multiple linear regression, and Likert Scale were used in the analysis. The average SUHII value, Beta coefficient, and mean value of the Likert scale for urbanization are the highest, followed by Land use and climate change. The average temperature induced by population density is 3.85 °C and its Beta value is 0.449 which is significant at p

Abstract Land surface temperature (LST) increases and urban heat island (UHI) variability are the major urban climatology problems arising in urban development. This study attempts to assess the effects of urban land use and land cover change on microclimate dynamics in Addis Ababa city. Three different sets of remotely sensed data from Landsat 5 TM (1990), Landsat 7 ETM+ (2005) and Landsat 8 OLI/TIRS (2021) were used for the study. LSTs were retrieved from Landsat5 TM and Landsat7 ETM+ using a mono window,and the thermal infrared band (TR-10) of Landsat–8 was used to retrieve LST. Regression and correlation analyses of the LST, normalized difference vegetation index (NDVI) and normalized difference built-up index (NDBI) were performed in SPSS V23. The study also examined the different residential urban morphology types (UMTs) of the LST and NDVI. The selected built-up blocks of UMTs included apartments, villas and mud houses. These UMTs are extracted by digitizing them from the Google Earth explorer. The results from this study showed that the proportion of urban green space (UGS) to other LULC types decreased from 120.4 km2 in 1990 to 76.26 km2 in 2021. However, the built-up area increased at a rate of 216.5 km2 (39.03%) from 1990 to 2021. The rapid expansion of built-up land in the study area was the main factor influencing the increase in LST. The residential UMTs exhibited significant differences in mean LSTs and NDVIs. The results indicate that UMT inhibited by Villia had the highest mean NDVI value and that the highest mean LST was observed in Apartment. The results of multiple linear regression analysis clearly indicate that built-up and green vegetation contributed 92.2% of the LST variations with R2 = 0.92 and VIF ≤ 10 in Addis Ababa city. The results of the study indicate that strengthening public participation in urban greening and optimizing the NDVI and NDBI are important strategies for mitigating the effects of microclimate change and that sustaining urban development and providing better quality of life for the urban population are important.

Urban heat islands are an environmental hazard which degrade people's lives worldwide, reducing social life and increasing health problems, forcing scientists to design innovative acclimatization methods in public places, such as sheltering. This paper focuses on providing quantitative indicators about airflow rates and qualitative information about airflow patterns in street canyons for typical street canyon morphologies, which is essential when designing outdoor acclimatization strategies to mitigate urban overheating. This is based on CFD simulations using an enhanced numerical domain model, which can reduce computational cost and simulation time. The study is performed for different ARs, from wide (AR = 0.75) to narrow (AR = 4), and wind speed to characterize their effect on street ventilation The results show that air renewal decreases while the AR increases. The reduction is faster for a low AR and then comes to a standstill for a high AR. In addition, the study shows that inside narrow streets, the pattern of airflow is affected by the wind velocity magnitude. These findings provide numerical values of air ventilation for a wide range of typical street canyon configurations, which represent essential data for designing effective climate control strategies, mitigating urban heat islands and conducting outdoor thermal comfort studies. This work contributes valuable knowledge to the multidisciplinary efforts aimed at enhancing urban living environments. [ABSTRACT FROM AUTHOR]

This research presents a GIS-based framework used to detect urban heat islands and determine which urban settlement elements are most critical when heatwave risks exist. The proposed method uses the Iterative Self-Organizing Data Analysis (ISODATA) clustering algorithm applied to the satellite land surface temperature distribution recorded during heatwaves for the detection of urban heat islands. A pixel classification confidence level maximization approach, obtained by running a maximum likelihood classification algorithm, is performed to determine the optimal number of clusters. The areas labeled as hotspots constitute the detected urban heat islands (UHIs). This method was tested on an urban settlement set up by the municipality of Naples (Italy). Comparison tests were performed with other urban heat island detection methods such as standard deviation thresholding and Getis-Ord Gi* hotspot detection; indices measuring the density of buildings, the percentage of permeable open spaces, and vegetation cover are taken into consideration to evaluate the accuracy of the urban heat islands detected. These tests highlight that the proposed method provides the most accurate results. It could be an effective tool to support the decision maker in evaluating which urban areas are the most critical during heatwave scenarios. [ABSTRACT FROM AUTHOR]

Cities frequently experience urban heat islands (UHIs), defined as regions where the urban environment is warmer than the rural surroundings. These characteristics are a direct result of urbanization, which eliminates natural vegetation and water sources and replaces them with impermeable surfaces with low albedo. Due to the urban heat island effect (UHI), cities are especially vulnerable to excessive heat events. The relationship between UHI and urban thermodynamics is explained by recent studies in the physical sciences, and these studies lay the groundwork for understanding how changes in the physical environment affect microclimates. The purpose of the study is to analyses the development of urban climate change as well as the technology used to mitigate it. Significant effort has been made in this particular time frame to comprehend and monitor urban climate change as well as to design and test alternative mitigation methods in high density residential areas of Delhi. The research The case of Delhi, India, using the microclimate modeling system ENVI-met, which models the temperature effects of various construction situations, has been analyzed in this paper. As a result, after applying all possible intervention, we conclude that in all other strategy temperature is increasing as comparison to base case so applying high emissivity paint on facade and green roof is the best strategy to mitigate high temperature in urban area. [ABSTRACT FROM AUTHOR]

Land surface temperature (LST) increases and urban heat island (UHI) variability are the major urban climatology problems arising in urban development. This study attempts to assess the effects of urban land use and land cover change on microclimate dynamics in Addis Ababa city. Three different sets of remotely sensed data from Landsat 5 TM (1990), Landsat 7 ETM+ (2005) and Landsat 8 OLI/TIRS (2021) were used for the study. LSTs were retrieved from Landsat5 TM and Landsat7 ETM+ using a mono window,and the thermal infrared band (TR-10) of Landsat–8 was used to retrieve LST. Regression and correlation analyses of the LST, normalized difference vegetation index (NDVI) and normalized difference built-up index (NDBI) were performed in SPSS V23. The study also examined the different residential urban morphology types (UMTs) of the LST and NDVI. The selected built-up blocks of UMTs included apartments, villas and mud houses. These UMTs are extracted by digitizing them from the Google Earth explorer. The results from this study showed that the proportion of urban green space (UGS) to other LULC types decreased from 120.4 km2 in 1990 to 76.26 km2 in 2021. However, the built-up area increased at a rate of 216.5 km2 (39.03%) from 1990 to 2021. The rapid expansion of built-up land in the study area was the main factor influencing the increase in LST. The residential UMTs exhibited significant differences in mean LSTs and NDVIs. The results indicate that UMT inhibited by Villia had the highest mean NDVI value and that the highest mean LST was observed in Apartment. The results of multiple linear regression analysis clearly indicate that built-up and green vegetation contributed 92.2% of the LST variations with R2 = 0.92 and VIF ≤ 10 in Addis Ababa city. The results of the study indicate that strengthening public participation in urban greening and optimizing the NDVI and NDBI are important strategies for mitigating the effects of microclimate change and that sustaining urban development and providing better quality of life for the urban population are important. [ABSTRACT FROM AUTHOR]

India is one of the rapidly urbanizing major economies in the developing world. As it embarks on its urban transition, many small tier-2 cities are already experiencing a large-scale transformation. This study examines the effects of surface urban heat island intensity (SUHI) effect from 2001 to 2020 on a tropical coastal urban complex, Bhubaneswar and Cuttack, a rapidly expanding tier-2 twin city in the Eastern Indian region. Our study reveals a clear discernible annual nighttime SUHI for both Bhubaneswar and Cuttack (0.75 ± 0.08 and 1.22 ± 0.07 °C) with a growth rate of 0.18 ± 0.07 and 0.13 ± 0.07 °C/decade, respectively. Surprisingly, the annual daytime SUHI is weakening for Bhubaneswar. Both night and daytime SUHI showed substantial seasonality with a clear asymmetry during the day and night. Daytime urban cool island effect was observed for Cuttack with Bhubaneswar reporting weak SUHI for daytime during dry seasons. Around the periphery of the cities, the diurnal temperature range (DTR) was found to be the highest. Furthermore, A decrease of 2 °C in the DTR has been reported over the past two decades. The urbanization effect on the local thermal climate of both cities is seen beyond the physical urban limits. Such changes, even in tier-2 cities, have significant potential to modulate local climate and underscore the need for detailed studies in the rapidly urbanizing cities of India and the world to enable disaster resilience, climate-proofing, and sustainability. [ABSTRACT FROM AUTHOR]

Undoubtedly, urbanization has improved human living conditions. However, it has also altered the natural landscape, leading to negative consequences such as increased Land Surface Temperature (LST) and Urban Heat Island (UHI) due to the expansion of Impervious Surface (IS). Much research has been conducted in other countries on the effects of changing urban landscape structures on LST and UHI formation. However, in Sri Lanka, only a few studies have been available on this topic, primarily concentrating on major cities like Colombo. Impervious Surface is absorbing high amounts of solar energy as well, which accelerates the magnitude of UHI in urbanized areas. Remote Sensing indices such as the Normalized Difference Vegetation Index (NDVI), Normalized Difference Buildup Index (NDBI), UHI, and Environmental Criticality Index (ECI) can effectively be used to quantify the intensity of the UHI phenomenon. This study aimed to investigate the effect of spatiotemporal variations in IS and Green Surface (GS) on UHI, LST, and the environmental criticality in Galle Municipal Council (MC), Sri Lanka employing multi-temporal Landsat-5 and 8 data from four different periods: 1996, 2005, 2014, and 2022. Different geospatial techniques including supervised image classification, Urban-Rural Gradient Zone (URGZ) analysis, grid-based analysis, UHI profiles, and regression analysis were used in the study. The findings revealed that Impervious Surface increased by 42.3% (7.34 km2) while Green Surface had a decline of 22.5% (3.91 km2) during the concerned period. This landscape transition led to a 2.74 C increase in mean surface temperature in the study area, along with a 9.5 C increase in the UHI index during 26 years. The results further revealed that Impervious Surface rapidly developed within 4 km (URGZ1-19) from city center, while Green Surface decreased. Newly built-up areas within the 1.5 km gradient (URGZ1-URGZ8) were more affected by increased LST. A positive correlation was identified between NDBI and LST, especially in the year 2022, with an R2 of 0.457, while NDVI and LST reported a negative R2 of 0.257. The grid-based analysis demonstrated an increasingly positive relationship between mean LST and the fraction of Impervious Surface, highlighting the role of built-up areas in raising LST and UHI in the MC. As a result, very high environmental critical areas have been concentrated in and around high-density Impervious Surface. Thus, it can be predicted that the UHI effect and Environmental Criticality (EC) may increase further in the future. In this context, planning agencies should prioritize green urban planning strategies, such as implementing green belts and urban agriculture in the study area, particularly in and around areas with high LST and high environmental criticality. This approach may help protect the natural environment and sustainably ensure the health of the urban community.

The rise in outdoor temperatures and heatwaves highlights the limitations of buildings in adapting to warming conditions, even in temperate climates. This paper analyses the indoor overheating of residential dwellings in Pamplona (a city in northern Spain, with a Cfb climate) using an urban-scale diagnostic methodology and presents different envelopes' retrofitting scenarios as a strategy to reduce it. The results come from energy simulations conducted during an extremely warm summer in 2022, considering the microclimate effects. The residential typologies most vulnerable to overheating are those with only one orientation, built before the EPBD 2002, and located on top floors. These dwellings show a 23.7% mean of indoor overheating hours (IOH), representing approximately 870 h above the EN 16798-1:2019 adaptive threshold from May to September. Renovating building envelopes to meet current energy standards reduces the IOH by an average of 8.6% and up to 15.35% in the most vulnerable typologies. In the retrofitting scenario with green roof systems, indoor temperatures are up to 0.5 °C lower than when roofs are renovated with traditional systems. This study assists policy-makers in preventing the risk of overheating within cities and encourages them to promote nature-based solutions in order to adapt urban residential buildings and cities to warming conditions. [ABSTRACT FROM AUTHOR]

In the summer of 2022, an intense heatwave swept through Northern Europe, with London bearing a significant impact. While nature-based solutions are often considered to be ideal responses to such heatwaves, experiences from the 2022 heatwave and others revealed potential drawbacks, particularly for urban green spaces. Prolonged dry spells, frequently accompanying heatwaves, result in excessively dry soil and the subsequent decline of vegetation in large parks. In the present study, microclimate simulations were conducted for Hyde Park in London, a location that experienced such drought during the 2022 heatwave, to examine its microclimatic performance in terms of thermal comfort and tree health. In alignment with the observations, ENVI-met could replicate the lack of noticeable cooling effects during the daytime and only marginal cooling during the nighttime. To address these challenges, mitigation scenarios were explored, incorporating heat mitigation measures such as part-time irrigation, temporary sun sails, and façade greenery. The findings demonstrated that implementing these measures could reduce heat stress by up to 13 K PET (physiologically equivalent temperature). These practical solutions emerged as effective remedies for mitigating the impact of heatwaves on urban green spaces and, hence, improving future urban development overall. [ABSTRACT FROM AUTHOR]

The phenomenon of the Urban Heat Island (UHI) is a common feature in city climates, impacting habitat quality and public health. The UHI refers to the temperature difference between metropolitan and countryside areas. This article introduces a new methodology for determining UHI using a high-resolution temperature map created by fusing Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite Systems (GNSS) measurements. The validity of this method has been assessed by comparing the UHI results with the outputs of the Weather Research and Forecasting (WRF) model. Using the new approach, temperature determination focuses on the moist segment of the tropospheric delay. The wet tropospheric delay is divided into turbulent and non-turbulent components, with the first segment calculated using InSAR and the second using GNSS observations. After generating high-resolution temperature maps to compute the temperature difference between urban and non-urban regions and defining the UHI index, the research area was categorized into various classes based on land cover using the Local Climate Zone Classification (LCZ) approach. Finally, after calculating the UHI in different regions, the results were evaluated against the WRF model outputs. According to the statistical evaluations, the Root Mean Square Error (RMSE) of the UHI index obtained from the novel method and the WRF model outputs ranges from 0.7 to 0.4 Kelvin. The determination coefficient (R2) also varies from 0.85 to 0.9 in different months. These statistical markers illustrate the significant effectiveness of the suggested technique in computing the UHI phenomenon.

Climate change significantly impacts transportation infrastructure, particularly asphalt pavements. Similarly, the heat absorption of paved surfaces, especially conventional black pavements, significantly intensifies the urban microclimate. Paved surfaces, including asphalt pavements, account for over 30% of the covered surfaces and are vulnerable to rising temperatures, which cause not only pavement distress, such as rutting and cracking, but also urban heat islands (UHI). Sustainable pavement solutions, specifically colored pavements, have been investigated for their potential to mitigate these effects. This review presents an extensive overview of current pavement technologies, emphasizing conventional asphalt’s economic, environmental, and functional characteristics. A discussion of the benefits and challenges of colored pavements is also provided, including their ability to reduce UHI, enhance safety, and contribute to sustainable urban growth. This paper discusses advancements in pavement material science, the use of recycled materials, and the application of reflective coatings, providing insights into sustainable infrastructure development. Transitioning from conventional black pavements to sustainable colored alternatives is not merely a matter of material choice but a strategic transition toward resilient urban planning. Increasing demand for environmentally friendly infrastructure could prompt the construction industry to adopt colored pavements as a tool to promote environmental stewardship.

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).

Adopting a multiscale approach is crucial for optimizing urban and building performance, prompting inquiries about the link between a technology’s local efficiency (building scale) and its broader impact (city-wide). To investigate this correlation and devise effective strategies for enhancing building and city energy performance, we experimentally examined a commercial nano-ceramic Thermal Barrier Coating (TBC) on a small-scale building and assessed numerically its influence on mitigating Urban Heat Islands (UHIs) at a city scale, translated in our case by the use of the thermal comfort index: the Universal Thermal Climate Index (UTCI). Our results reveal that the coating significantly curbs heat transfer locally, reducing surface temperatures by over 50 ∘C compared to traditional roofs and attenuating more than 70% of heat flux, potentially alleviating air conditioning demands and associated urban heat effects. However, implementing such coatings across a city does not notably advance overall efficiency and might trigger minor overheating on thermal perception. Hence, while nano-ceramic coatings indirectly aid UHI mitigation, they are not a standalone fix; instead, an integrated strategy involving efficient coatings, sustainable urban planning, and increased vegetation emerges as the optimal path toward creating enduringly sustainable, pleasant, and efficient urban environments to counter urban heat challenges effectively.

Chlorophyll (Chl) fluorescence induction (FI) upon a dark–light transition has been widely analyzed to derive information on initial events of energy conversion and electron transfer in photosystem II (PSII). However, currently, there is no analytical solution to the differential equation of QA reduction kinetics, raising a doubt about the fitting of FI by numerical iteration solution. We derived an analytical solution to fit the OJ phase of FI, thereby yielding estimates of three parameters: the functional absorption cross-section of PSII (σPSII), a probability parameter that describes the connectivity among PSII complexes (p), and the rate coefficient for QA− oxidation (kox). We found that σPSII, p, and kox exhibited dynamic changes during the transition from O to J. We postulated that in high excitation light, some other energy dissipation pathways may vastly outcompete against excitation energy transfer from a closed PSII trap to an open PSII, thereby giving the impression that connectivity seemingly does not exist. We also conducted a case study on the urban heat island effect on the heat stability of PSII using our method and showed that higher-temperature-acclimated leaves had a greater σPSII, lower kox, and a tendency of lower p towards more shade-type characteristics. [ABSTRACT FROM AUTHOR]

The rapid growth of urban population has significantly changed human settlement patterns, leading to a decline in air quality and changes in climatic conditions in urban areas. Trees are recognized as nature-based solutions because they can remove particles from the air and regulate the climate. However, trees are negatively affected by pollution and temperatures, which represent a challenge for urban planning, management, and human health. To assess the impact of urban pollution and warmer climates on functional traits, we conducted a study using Quercus humboldtii , an endangered tree species endemic to Colombia and Panamá that dominates Andean forests and urban green areas in Bogotá. We selected three localities with contrasting pollution levels and climate conditions and measured 10 morphological and biochemical traits in six individuals at each location. Our findings revealed that Q. humboldtii adjusted morphological and biochemical traits in response to the environmental challenges posed by urban environments. The functional strategies varied between individuals with thin and large leaves and acidic pH in the colder and unpolluted native forest, while others displayed a conservative resource strategy (high leaf dry matter content) and neutral pH in the warmer and most polluted locality. Despite these differences, several traits indicate that Q. humboldtii is not a species tolerant to pollution. This is further supported by the air pollution tolerance index (APTI) values. Our results suggest that Q. humboldtii should be planted in areas of Bogotá with low pollution levels in order to promote its long-term survival and support ecosystem services. [ABSTRACT FROM AUTHOR]

The surface urban heat island (SUHI) is caused by a combination of variables, broadly classified as climate change, land use change, and urbanization. They have varying degrees of influence depending on their level of intensity. As a result, recognizing the primary cause is critical to resolving the issue and developing suitable policies to reduce resource waste. This study attempted to identify the underlying cause of SUHI by primarily evaluating the intensity of the surface urban heat island using primary and secondary data. Zonal Statistics, the Mann-Kendall trend test, Oke's UHI model, multiple linear regression, and Likert Scale were used in the analysis. The average SUHII value, Beta coefficient, and mean value of the Likert scale for urbanization are the highest, followed by Land use and climate change. The average temperature induced by population density is 3.85 °C and its Beta value is 0.449 which is significant at p < 0.01. The mean value of the Likert scale is also the highest 3.62 as compared to the other two. It can be concluded that urbanization is the primary culprit that instigates SUHI in the study area, influenced by the incoming population from the surrounding satellite towns and rural areas. These findings help urban planners and greening designers make appropriate urban planning and thermal management decisions. [ABSTRACT FROM AUTHOR]

This study provides an overview of how phase change materials (PCMs) can improve the resistance of concrete pavement to freeze–thaw cycles and mitigate the urban heat island (UHI) effect. The investigation covers different types of PCMs and methods for integrating them into concrete pavement, as well as the mechanical properties and compressive strength of concrete pavement when employing various PCMs. Prior studies have identified porous aggregates, microencapsulation, and pipelines containing liquid PCM as common approaches for PCM integration. Researchers have observed that the utilization of PCMs in concrete pavement yields favorable thermal properties, suggesting the potential for anti-freezing and UHI mitigation applications. However, the choice of PCM materials should be informed by local climate conditions. [ABSTRACT FROM AUTHOR]

This research presents a GIS-based framework used to detect urban heat islands and determine which urban settlement elements are most critical when heatwave risks exist. The proposed method uses the Iterative Self-Organizing Data Analysis (ISODATA) clustering algorithm applied to the satellite land surface temperature distribution recorded during heatwaves for the detection of urban heat islands. A pixel classification confidence level maximization approach, obtained by running a maximum likelihood classification algorithm, is performed to determine the optimal number of clusters. The areas labeled as hotspots constitute the detected urban heat islands (UHIs). This method was tested on an urban settlement set up by the municipality of Naples (Italy). Comparison tests were performed with other urban heat island detection methods such as standard deviation thresholding and Getis-Ord Gi* hotspot detection; indices measuring the density of buildings, the percentage of permeable open spaces, and vegetation cover are taken into consideration to evaluate the accuracy of the urban heat islands detected. These tests highlight that the proposed method provides the most accurate results. It could be an effective tool to support the decision maker in evaluating which urban areas are the most critical during heatwave scenarios.

Rising temperatures, a major global environmental challenge, negatively impact health, the environment, society, and the economy. Surface Urban Heat Islands (SUHI), exacerbated by urbanization and climate change, intensify vulnerabilities for urban areas and residents. Urban planning and design aime to reduce these vulnerabilities through large-scale and small-scale interventions. However, addressing the significance of the capillary effects resulting from small-scale interventions and bottom-up community engagement is important. Urban acupuncture (UA) is an emerging approach in contemporary urban planning and design that focuses on small-scale interventions to mitigate the effects of SUHIs at the community level. This study develops a framework for mitigating the impacts of SUHIs through UA implementation in urban design. The proposed framework consists of two key phases: diagnosis and prescription. During the diagnosis phase, we analyzed heat-vulnerable points to identify indicators contributing to the development and exacerbation of the SUHIs. Then, we employed the Matrix of Cross Impact Multiplications Applied to a Classification (MICMAC) technique to comprehensively assess 75 influential indicators related to urban structure across various aspects and scales, focusing on the mesoscale. Among them, 30 leading indicators were identified, of which environmental and morphological indicators emerged as significant catalysts. Moving on to the prescription phase, we developed a UA-based framework called the “5 Wh Question” which addresses five fundamental questions: why, who, what, how, and where. Our findings can provide comprehensive solutions for policymakers and urban planners to address the identified heat-vulnerable points.

This work examines the topoclimatic characteristics of Zahlé, specifically thermal breezes and the Urban Heat Island (UHI) phenomenon. Three-hourly data from 1994 to 2021 from conventional weather stations shows a frequency of breezes in the summer season of 74%. In Rayak, mountain and valley breezes have been noticed alternating between day and night, channeled by the topography of the Bekaa Valley. In Houch El Oumaraa, valley-sea breezes dominate during the day and mountain breezes occur at night. These breezes affect the distribution of air temperature and humidity, creating an average thermal contrast of 4.3°C between the city and its surrounding countryside at night. Data from weather stations implanted in 2022 and car surveys at a fine scale (half hourly data) level has confirmed the previous findings: During nighttime, the mountain breeze dominates and brings cool and moist air from the mountains into the valley at a low speed (<1 m/s). During the daytime, a valley breeze dominates and can reach speeds of up to 4 m/s. Additionally, a sea breeze with faster speeds is detected. The car surveys indicate a temperature variation of 9 °C between the valley and the surrounding urban areas during early morning. [ABSTRACT FROM AUTHOR]

Climate change elevates the rate of emergence of urban heat islands (UHIs), especially in the tropics. UHIs severely affect human comfort and health. Many studies have suggested that urban areas should be properly mitigated or planned. To cope with this, it is best to present the issue using easy-to-understand approaches to allow for better decision-making, especially during urban planning. Based on the information, adaptations and mitigation strategies can be suggested in order to reduce the impact. Hence, this research was aimed at determining the heat vulnerability index (HVI) of urban areas. This study was conducted in Malaysia in the Klang Valley, a tropical city with a complex urban morphology. Remote sensing techniques were employed to extract and derive the spatial index values for exposure, sensitivity, and adaptive capacity. A principal component analysis (PCA) was used to estimate the vulnerability as well as to generate the HVI. The most vulnerable districts were found to be Petaling (1.00), Kuala Lumpur (0.99), and Putrajaya (0.95). Kuala Lumpur had a level of exposure that was high (0.56), a level of sensitivity that was high (0.84), and capacity to adapt that was low (0.54), while Petaling had a high exposure value (0.56), very high sensitivity (1), and high adaptive capacity (0.72). A Pearson's correlation (r) test also revealed that the variables used were highly correlated. From the preliminary findings, the vulnerability of the population to high temperatures in the Klang Valley can be identified to help develop adaptative plans that are targeted as a response to rapid warming in the future in Malaysia. [ABSTRACT FROM AUTHOR]

Lahore is the second major metropolitan city in Pakistan in terms of urban population and built-up area, making the city a more ideal place to form the surface urban heat island (SUHI) effects. In the last two decades, the considerable land-use conversion from a natural surface (vegetation) and permeable (waterbody) surface into an impervious (built-up area) surface has lead to an increase in land surface temperature (LST) in Lahore. The human thermal comfort (HTC) of the residents is also impacted by the higher LST. The present study uses multi-temporal Landsat (5&8) satellite imageries to examine the ecological and thermal conditions of Lahore between 2000 and 2020. The ecological and thermal conditions of Lahore are assessed by calculating the urban heat islands and UTFVI (urban thermal field variance index), based on LST data which quantitatively assessed the UHI effect and the quality of human life. The outcomes establish that the urban built-up area has increased by 18%, while urban vegetation, vacant land, and waterbody decreased by 13%, 4%, and 0.04%, respectively. In the last 20 years, the mean LST of the study region has risen by about 3.67 °C. The UHI intensity map shows intensification and a rise in surface temperature variation from 4.5 °C (2000) to 5.9 °C (2020). Furthermore, the finding shows that the ecological and thermal conditions are worse in construction sites, transition zones, and urban areas in comparison to nearby rural areas. The lower UTFVI was observed in dense vegetation cover areas while a hot spot of higher UTFVI was predominantly observed in the areas of transition zones and built-up area expansion. Those areas with higher hot spots are more vulnerable to the urban heat island effect. The main conclusions of this study are essential for educating city officials and urban planners in developing a sustainable urban land development plan to reduce urban heat island effects by investing in open green spaces for urban areas of cities. [ABSTRACT FROM AUTHOR]

Adopting a multiscale approach is crucial for optimizing urban and building performance, prompting inquiries about the link between a technology's local efficiency (building scale) and its broader impact (city-wide). To investigate this correlation and devise effective strategies for enhancing building and city energy performance, we experimentally examined a commercial nano-ceramic Thermal Barrier Coating (TBC) on a small-scale building and assessed numerically its influence on mitigating Urban Heat Islands (UHIs) at a city scale, translated in our case by the use of the thermal comfort index: the Universal Thermal Climate Index (UTCI). Our results reveal that the coating significantly curbs heat transfer locally, reducing surface temperatures by over 50 ∘ C compared to traditional roofs and attenuating more than 70% of heat flux, potentially alleviating air conditioning demands and associated urban heat effects. However, implementing such coatings across a city does not notably advance overall efficiency and might trigger minor overheating on thermal perception. Hence, while nano-ceramic coatings indirectly aid UHI mitigation, they are not a standalone fix; instead, an integrated strategy involving efficient coatings, sustainable urban planning, and increased vegetation emerges as the optimal path toward creating enduringly sustainable, pleasant, and efficient urban environments to counter urban heat challenges effectively. [ABSTRACT FROM AUTHOR]

Much of the urbanization that occurs in Africa creates the potential for technological development and economic growth but is also a breeding ground for environmental and health problems. This study was undertaken to evaluate the urban-induced land use/land cover (LULC) change and its contribution to the land surface temperature (LST) and urban heat fluxes from 2001 to 2021. More specifically, the study analyzed different scenarios of LULC change and retrieved the LST to evaluate the trends of the urban heat flux (UHI) in response to the urban-induced LULC change. The analysis of LULC change from 2001 to 2021 indicated that built-up and bare land showed the highest rate of increase at the expense of declining open spaces, agricultural land, and vegetation areas. The built-up areas in Nekemte and Jimma City increased by 929.25 ha (172.75%) and 2285.64 ha (226.93%) over the investigated period, respectively. The highest changes in LULC are seen in built-up areas followed by agricultural land, while the smallest changes are shown by water body followed by bare land. Built-up areas showed the highest net gain, while agricultural land experienced the greatest loss. In areas where the vegetation cover is low, low LST was depicted, and high LST was shown in areas where built-up areas were concentrated in both cities. Due to the LULC changes, the average LST increased by 1.9 °C and 2.2 °C in Nekemte and Jimma City, respectively, over the last 21 years. The urbanization-induced LULC change does not only cause changes in the hydrological process but also changes in the thermal variations and urban heat stress of the two urban centers. The result indicates that the increases in vegetation and green areas are significant in improving the heat stress and thermal characteristics of urban areas. Overall, to achieve sustainable urban development, the integration of land use with urban planning policies could be critical to the resilience of local environment and urban ecosystem. [ABSTRACT FROM AUTHOR]

Although the urban heat island (UHI) phenomenon is more commonly studied in summer, its influence is also important in winter. In this study, the authors focused on the winter UHI in Ljubljana (Slovenia) and its impact on the urban population, as well as in comparison with a UHI study from 2000. Through a combination of mobile and stationary temperature measurements in different parts of the city, the winter intensity of the UHI in Ljubljana was studied in a dense spatial network of measurements. It was found that the intensity of the winter UHI in Ljubljana decreases as winters become warmer and less snowy. The results showed that the winter UHI in Ljubljana intensifies during the night and reaches the greatest intensity at sunrise. During the winter radiation type of weather, the warmest part of Ljubljana reaches an intensity of 3.5 °C in the evening. In total, 22% of the urban area is in the evening UHI intensity range of 2–4 °C, and 65% of the urban population lives in this range. In the morning, the UHI in Ljubljana has a maximum intensity of 5 °C. The area of >4 °C UHI intensity covers 7% of the urban area, and 28% of the total urban population lives in this area. Higher temperatures in urban centers in winter lead to a longer growing season, fewer snow cover days, lower energy consumption and cold stress, and lower mortality from cold-related diseases compared to the colder periphery.

ABSTRACT Land use/Land cover (LU/LC) modifications leads to rise in surface temperature is a global concern. This study investigates the effects of LU/LC changes in Land Surface Temperature (LST) variations and effects of Urban Heat Island (UHI) in Thiruvananthapuram city. Furthermore, the study proposed a novel heat stress vulnerability index (HSVI) using Analytical Hierarchy Process (AHP) method. Results shows that transformation of all land uses is to built-up areas, which shows an increase of +118.46% where as others such as vegetation (-24.27%), open area (-64.315) and waterbody (-43.88%) shows drastic decrease over 34 years. The relationship between Normalized Difference Vegetation Index and LST shows a significant change with R2 values between 0.223 in 1988, 0.382 in 2000 and 0.253 in 2022. Moreover, this also contributed to the increase of the mean LST of 26.96 ºC in 1988 to 28.52 ºC in 2022. HSVI of the study indicates that 30.83% of the study area is categorized as very low heat stress vulnerable area followed by 37.22% area in low heat stress vulnerability, 17.88% in moderate heat stress vulnerability, 8.87% in high heat stress vulnerability and 5.19% of the area falling in very high heat stress Vulnerability class.

Exploring the spatiotemporal patterns of urban thermal environments is crucial for mitigating the detrimental effects of urban heat islands (UHI). However, the long-term and fine-grained monitoring of UHI is limited by the temporal and spatial resolutions of various sensors. To address this limitation, this study employed the Google Earth Engine (GEE) platform and a multi-source remote sensing data fusion approach to generate a densely time-resolved Landsat-like Land Surface Temperature (LST) dataset for daytime observations spanning from 2001 to 2020 in Shanghai. A comprehensive analysis of the spatiotemporal patterns of UHI was conducted. The results indicate that over the past 20 years, the highest increase in average LST was observed during spring with a growth coefficient of 0.23, while the lowest increase occurred during autumn (growth coefficient of 0.12). The summer season exhibited the most pronounced UHI effect in the region (average proportion of Strong UHI and General UHI was 28.73%), while the winter season showed the weakest UHI effect (proportion of 22.77%). The Strong UHI areas gradually expanded outward over time, with a noticeable intensification of heat island intensity in the northwest and coastal regions, while other areas did not exhibit significant changes. Impervious surfaces contributed the most to LST, with a contribution of 0.96 °C, while water had the lowest contribution (−0.42 °C). The average correlation coefficients between LST and NDVI, NDWI, and NDBI over 20 years were −0.4236, −0.5128, and 0.5631, respectively. [ABSTRACT FROM AUTHOR]

Introduction: The term "urban heat island" refers to a phenomenon that occurs when temperatures in urban areas are higher than those in the areas that surround them (suburban area). Methods: The urban heat island phenomenon can result in increase of energy consumption, increase of air pollution, decrease of water quality, and increase of greenhouse gas emissions, all of which have the potential to negatively impact people in a variety of ways. Results: In this review we identified certain groups such as elderly, children, woman, pregnant woman, single person, and minority communities, who are living in dense area or in high rise building, low education level, low income, work in outdoor environment and had pre-existing illnesses may face health issues or insufficient resources to cope with the heat in urban area. There were more susceptible to heat-related illnesses and mortality, particularly during extreme heat events. Conclusions: Recognising these vulnerable populations is crucial to develop effective strategies to mitigate the effects of urban heat islands and protect them. This can aid policy makers and urban planners to implement targeted interventions to address these issues. [ABSTRACT FROM AUTHOR]

This study aimed to accurately grasp the impact mechanism and change rule of buildings and green spaces on land surface temperature (LST), which is of great significance for alleviating urban heat islands (UHIs) and formulating adaptation measures. Taking Jinan, China, as the study area, combined multisource remote sensing data were used in this study to construct an index system of the influencing factors. We used a spatial regression model to explore the relative contribution of the influencing indicators on LST. We also drew a marginal utility curve to quantify the heating/cooling effect of the leading indicators. The results showed that, firstly, among the 3D building indicators, the leading indicators affecting LST were the degree of spatial convergence (SCD) and the building surface area (BSA). Among the green space indicators, the largest patch index (LPI), green coverage rate (GCR), and edge density (ED) were significantly negatively correlated with LST. Secondly, when we considered the 15 indicators comprehensively, SCD was the most influential indicator, with a contribution of 24.7%, and the contribution of the green space indicators to LST was significantly reduced. Thirdly, among the leading indicators, SCD was positively correlated with LST. When SCD was less than 60%, LST increased by about 0.38 °C for every 10% increase. When GCR > 44%, LST was significantly reduced, and when GCR > 62%, a cooling effect of 1.1 °C was observed. Beyond this threshold, the cooling effect will not improve significantly. This study shows that when 3D buildings are densely distributed and crowded, the cooling effect of green space will be limited to some extent by 3D buildings. The key to mitigating UHIs is to rationally configure and optimize the spatial structure of 3D buildings. [ABSTRACT FROM AUTHOR]

Urbanization and warming climate suggest that health impacts from extreme heat will increase in cities, thus locating vulnerable populations is pivotal. However, heat vulnerability indices (HVI) overwhelmingly interpret one model that may be inaccurate or methodologically flawed without considering how results compare with other HVI. Accordingly, this analysis applied a multimodal approach incorporating underrepresented health and adaptability measures to analyze heat vulnerability more comprehensively and better identify vulnerable populations. The Southeast Florida HVI (SFHVI) blends twenty-four physical exposure, sensitivity, and adaptive capacity indicators using uncommon statistical weights removing overlap, then SFHVI scores were compared statistically and qualitatively with ten models utilizing alternative methods. Urban areas with degraded physical settings, socioeconomic conditions, health, and household resources were particularly vulnerable. Rural and agricultural areas were also vulnerable reflecting socioeconomic conditions, health, and community resources. Three alternative models produced vulnerability scores not statistically different than SFHVI. The other seven differed significantly despite geospatial consistency regarding the most at-risk areas. Since inaccurate HVI can mislead decisionmakers inhibiting mitigation, future studies should increasingly adopt multimodal approaches that enhance analysis comprehensiveness, illuminate methodological strengths and flaws, as well as reinforce conviction about susceptible populations. [ABSTRACT FROM AUTHOR]

Although the urban heat island (UHI) phenomenon is more commonly studied in summer, its influence is also important in winter. In this study, the authors focused on the winter UHI in Ljubljana (Slovenia) and its impact on the urban population, as well as in comparison with a UHI study from 2000. Through a combination of mobile and stationary temperature measurements in different parts of the city, the winter intensity of the UHI in Ljubljana was studied in a dense spatial network of measurements. It was found that the intensity of the winter UHI in Ljubljana decreases as winters become warmer and less snowy. The results showed that the winter UHI in Ljubljana intensifies during the night and reaches the greatest intensity at sunrise. During the winter radiation type of weather, the warmest part of Ljubljana reaches an intensity of 3.5 °C in the evening. In total, 22% of the urban area is in the evening UHI intensity range of 2–4 °C, and 65% of the urban population lives in this range. In the morning, the UHI in Ljubljana has a maximum intensity of 5 °C. The area of >4 °C UHI intensity covers 7% of the urban area, and 28% of the total urban population lives in this area. Higher temperatures in urban centers in winter lead to a longer growing season, fewer snow cover days, lower energy consumption and cold stress, and lower mortality from cold-related diseases compared to the colder periphery. [ABSTRACT FROM AUTHOR]

In the face of climate change and constantly progressing urbanization processes, so-called heat islands are observed with growing frequency. These phenomena are mainly characteristic of large cities, where increased air and land surface temperatures form an atmospheric (AUHI) or surface (SUHI) urban heat island (UHI). Moreover, UHIs have also been recognized in the underground environments of many cities worldwide, including groundwater (GUHI). However, this phenomenon is not yet as thoroughly studied as AUHI and SUHI. To recognize and characterize the thermal conditions beneath the city of Wrocław (SW, Poland), we analyze the groundwater temperature (GWT) of the first aquifer, measured in 64 wells in 2004–2005. The study aimed to identify groundwater urban heat islands (GUHI) in Wrocław. Therefore, we used a novel approach to gather data and analyze them in predefined seasonal periods. Meteorological data and satellite imagery from the same period allowed us to link GWT anomalies to the typical conditions that favor UHI formation. GWT anomaly related to the GUHI was identified in the central, urbanized part of Wrocław. Moreover, we found that the GUHI phenomenon occurs only seasonally during the winter, which is related to the city's climate zone and anthropogenic heat sources. Comparing our results with previous works from other cities showed untypical behavior of the observed anomalies. In contrast to AUHI and SUHI temperatures, the GWT anomalies detected in Wrocław are characterized by seasonal transitions from a heat island in winter to a cold lake in summer. Such a transitional character of GUHI is described for the first time. [ABSTRACT FROM AUTHOR]

Chlorophyll (Chl) fluorescence induction (FI) upon a dark–light transition has been widely analyzed to derive information on initial events of energy conversion and electron transfer in photosystem II (PSII). However, currently, there is no analytical solution to the differential equation of QA reduction kinetics, raising a doubt about the fitting of FI by numerical iteration solution. We derived an analytical solution to fit the OJ phase of FI, thereby yielding estimates of three parameters: the functional absorption cross-section of PSII (σPSII), a probability parameter that describes the connectivity among PSII complexes (p), and the rate coefficient for QA− oxidation (kox). We found that σPSII, p, and kox exhibited dynamic changes during the transition from O to J. We postulated that in high excitation light, some other energy dissipation pathways may vastly outcompete against excitation energy transfer from a closed PSII trap to an open PSII, thereby giving the impression that connectivity seemingly does not exist. We also conducted a case study on the urban heat island effect on the heat stability of PSII using our method and showed that higher-temperature-acclimated leaves had a greater σPSII, lower kox, and a tendency of lower p towards more shade-type characteristics.

This study provides an overview of how phase change materials (PCMs) can improve the resistance of concrete pavement to freeze–thaw cycles and mitigate the urban heat island (UHI) effect. The investigation covers different types of PCMs and methods for integrating them into concrete pavement, as well as the mechanical properties and compressive strength of concrete pavement when employing various PCMs. Prior studies have identified porous aggregates, microencapsulation, and pipelines containing liquid PCM as common approaches for PCM integration. Researchers have observed that the utilization of PCMs in concrete pavement yields favorable thermal properties, suggesting the potential for anti-freezing and UHI mitigation applications. However, the choice of PCM materials should be informed by local climate conditions.

Quick population increase and the desire for urbanization are the main drivers for accelerating urban expansion on agricultural lands in Egypt. This issue is obvious in governorates with no desert backyards. This study aims to (1) explore the trend of Land Use Land Cover Change (LULCC) through the period of 1991–2018; (2) upgrade the reliability of predicting LULCC by integrating the Cellular Automata (CA)-Markov chain and fuzzy analytical hierarchy process (FAHP); and (3) perform analysis of urbanization risk on LST trends over the Gharbia governorate for the decision makers to implement effective strategies for sustainable land use. Multi-temporal Landsat images were used to monitor LULCC dynamics from 1991 to 2018 and then simulate LULCC in 2033 and 2048. Two comparable models were adopted for the simulation of spatiotemporal dynamics of land use in the study area: CA-Markov chain and FAHP-CA-Markov chain hybrid models. The second model upgrades the potential of the CA-Markov chain for prediction by its integration with FAHP, which can determine the locations of high potential to be urbanized. The outcomes stated a significant LULCC in Gharbia during the study period—specifically, urban sprawl on agricultural land, and this trend is predicted to carry on. The agricultural sector represented 91.2% in 1991 and reduced to 83.7% in 2018. The built-up area is almost doubled by 2048 with respect to 2018. The regression analysis revealed the LST increase due to urbanization, causing an urban heat island phenomenon. Criteria-based analysis reveals the district's vulnerability to rapid urbanization, which is efficient for data-gap zones. The simulation results make sense since the FAHP-CA-Markov simulated the LULCC in a thoughtful way, considering the driving forces of LULCC, while the CA-Markov chain results were relatively random. Therefore, the FAHP-CA-Markov chain is the pioneer to be relied upon for future projection. The findings of this work provide a better understanding of LULCC trends over the years supporting decision makers toward sustainable land use. Thus, further urbanization should be planned to avert the loss of agricultural land and uninterrupted increasing temperatures. [ABSTRACT FROM AUTHOR]