Urban Heat Island Research in Phoenix, Arizona: Theoretical Contributions and Policy Applications

A bibliometric analysis based on the Science Citation Index-Expanded (SCI-Expanded) database from the Web of Science was performed to review urban heat island (UHI) research from 1991 to 2015 and statistically assess its developments, trends, and directions. In total, 1822 papers published in 352 journals over the past 25 years were analyzed for scientific output; citations; subject categories; major journals; outstanding keywords; and leading countries, institutions, authors, and research collaborations. The number of UHI-related publications has continuously increased since 1991. Meteorology atmospheric sciences, environmental sciences, and construction building technology were the three most frequent subject categories. Building and Environment, International Journal of Climatology, and Theoretical and Applied Climatology were the three most popular publishing journals. The USA and China were the two leading countries in UHI research, contributing 49.56% of the total articles. Chinese Academy of Science, Arizona State University, and China Meteorological Administration published the most UHI articles. Weng QH and Santamouris M were the two most prolific authors. Author keywords were classified into four major groups: (1) research methods and indicators, e.g., remote sensing, field measurement, and models; (2) generation factors, e.g., impervious urban surfaces, urban geometry, waste heat, vegetation, and pollutants; (3) environmental effects, e.g., urban climate, heat wave, ecology, and pollution; and (4) mitigation and adaption strategies, e.g., roof technology cooling, reflective cooling, vegetation cooling, and urban geometry cooling. A comparative analysis of popular issues revealed that UHI determination (intensity, heat source, supporting techniques) remains the central topic, whereas UHI impacts and mitigation strategies are becoming the popular issues that will receive increasing scientific attention in the future. Modeling will continue to be the leading research method, and remote sensing will be used more widely. Additionally, a combination of remote sensing and field measurements with models is expected.

As global urbanization accelerates, the Urban Heat Island (UHI) effect has become a significant problem in urban environmental studies worldwide. Traditional research methods mainly include ground-based meteorological observations and numerical simulation analyses. Ground-based meteorological observations can provide detailed local climate data but are limited in coverage, while numerical simulation can replicate urban climate features through models, although input data and modeling parameters constrain its accuracy. In contrast, remote sensing technology, with its wide coverage, high resolution, and dynamic monitoring capabilities, has emerged as a powerful tool for monitoring the UHI effect. This study explores the advantages of remote sensing technology in UHI research, emphasizing its ability to provide comprehensive spatial and temporal data, enhance the accuracy of UHI detection, and offer insights that traditional methods cannot. Key indicators of remote sensing technology, such as land surface temperature, normalized difference vegetation index (NDVI), normalized difference built-up index (NDBI), and albedo, are used to analyze the UHI effect. The primary application of remote sensing technology in UHI research includes temporal and spatial distribution changes in UHI. Technological advancements in remote sensing and data processing could further enhance the ability to monitor, analyze, and mitigate the UHI effect.

Abstract. Along with urbanization, sealing of vegetated land and evaporation surfaces by impermeable materials, lead to changes in urban climate. This phenomenon is observed as temperatures several degrees higher in densely urbanized areas compared to the rural land at the urban fringe particularly at nights, so-called Urban Heat Island. Urban Heat Island (UHI) effect is related with urban form, pattern and building materials so far as it is associated with meteorological conditions, air pollution, excess heat from cooling. UHI effect has negative influences on human health, as well as other environmental problems such as higher energy demand, air pollution, and water shortage. Urban Heat Island (UHI) effect has long been studied by observations of air temperature from thermometers. However, with the advent and proliferation of remote sensing technology, synoptic coverage and better representations of spatial variation of surface temperature became possible. This has opened new avenues for the observation capabilities and research of UHIs. In this study, "UHI effect and its relation to factors that cause it" is explored for İzmit city which has been subject to excess urbanization and industrialization during the past decades. Spatial distribution and variation of UHI effect in İzmit is analysed using Landsat 8 and ASTER day & night images of 2015 summer. Surface temperature data derived from thermal bands of the images were analysed for UHI effect. Higher temperatures were classified into 4 grades of UHIs and mapped both for day and night. Inadequate urban form, pattern, density, high buildings and paved surfaces at the expanse of soil ground and vegetation cover are the main factors that cause microclimates giving rise to spatial variations in temperatures across cities. These factors quantified as land surface/cover parameters for the study include vegetation index (NDVI), imperviousness (NDISI), albedo, solar insolation, Sky View Factor (SVF), building envelope, distance to sea, and traffic space density. These parameters that cause variation in intra-city temperatures were evaluated for their relationship with different grades of UHIs. Zonal statistics of UHI classes and variations in average value of parameters were interpreted. The outcomes that highlight local temperature peaks are proposed to the attention of the decision makers for mitigation of Urban Heat Island effect in the city at local and neighbourhood scale.

The urban heat island (UHI) phenomenon is among the most evident features of human impact on the Earth’s system. This phenomenon has been widely observed and documented in many cities around the world. UHI-related publications have increased rapidly over the last three decades. However, because of a refined methodology and widening scope, a holistic understanding of research patterns and issues related to UHI research is lacking. Although others have summarized developments in UHI studies, these publications have focused on describing the current state of research rather than uncovering research trends and prospects. In the present study, we examined the evolution of UHI-related research from 1990 to 2017 and applied a scientometrics approach to identify research trends. The characteristics of publication outputs, key scientific disciplines, and cooperation between countries and institutions were determined by a citation analysis. We also discuss research trends, including future directions, approaches, and expected data. We identified two potential directions for UHI research through the results of key co-word clustering and discriminant analyses: negative impacts of UHI on public health and strategies to mitigate and adapt to UHI effects. We provide a broad review of the development of UHI research that may inspire future studies on the UHI phenomenon by new researchers in this field.

The impact of urban growth and climate change on heat stress in a sub-tropical Australian city

The urban planner's role should be adapted to the current globalised and over-specialised economic and environmental context, envisioning a balance at the regional scale, apprehending not only new technologies, but also new mapping principles, that allow obtaining multidisciplinary integral overviews since the preliminary stages of the design process. The urban heat Island (UHI) is one of the main phenomena aff ecting the urban climate. In the Netherlands, during the heat wave of 2006, more than 1,000 extra deaths were registered. UHI-related parameters are an example of new elements that should be taken into consideration since the early phases of the design process.

This study presents a bibliometric analysis of urban heat island (UHI) research published between 2015 and 2024, based on a dataset of 5,144 publications. The analysis examines publication types, disciplinary and geographic distributions, author collaborations, and keyword clusters using VOSviewer. UHI research was found to be predominantly concentrated in environmental science, remote sensing, and ecology, with China and the USA as leading contributors. Thematic trends emphasize topics such as land surface temperature, evapotranspiration, Normalized Difference Vegetation Index (NDVI), and nature-based mitigation strategies. Despite increasing interest, small and medium-sized cities, as well as socio-economic dimensions, remain underrepresented. Methodologically, the field has evolved from basic observational mapping to advanced analytical approaches involving Geographic Information System (GIS), machine learning, and multi-scalar modeling. By offering a replicable and integrative framework, this study contributes to the standardization of bibliometric research in the UHI domain and supports future interdisciplinary and internationally coordinated studies.

粒度变化对城市热岛空间格局分析的影响

The Chishui River Basin, a vital waterway in Southwest China, has experienced rapid urbanization, leading to significant ecological and environmental changes, among which the urban heat island (UHI) effect is particularly pronounced. The UHI effect not only affects the quality of life for residents but also influences urban energy consumption and climate change, underscoring the need for in-depth study of its spatial distribution and contributing factors. The unique karst topography of the region further complicates UHI research, necessitating an investigation that can inform urban planning and sustainable development strategies. This study leveraged Landsat 8 TIRS satellite remote sensing imagery to examine the land surface temperature (LST) and UHI effect in the Chishui River Basin during the summers of 2016 and 2021. Employing the Mono-window Algorithm (MWA), the research quantitatively inverted the LST and analyzed its spatial distribution and the spatiotemporal characteristics of the surface urban heat island (SUHI) effect. The findings indicated a notable increase in average summer temperatures between the 2 years, with a 1.67°C rise from 2016 to 2021. Despite this increase, there was an observed reduction in the extent of SUHI areas, suggesting potential mitigation efforts. Additionally, the study revealed that karst regions were more susceptible to forming “abnormal” heat islands due to their distinct geomorphological features. The implications of this research are critical for urban development planning and the pursuit of sustainable urbanization in the Chishui River Basin. By understanding the thermal dynamics and their relationship with urbanization and karst landscapes, policymakers and urban planners can devise strategies to minimize the adverse effects of SUHI while promoting ecological balance and environmental health. Future research should extend the temporal analysis, employ higher resolution data, compare findings with other regions, and provide a detailed examination of mitigation efforts to enhance the robustness and applicability of the conclusions, provide stronger scientific evidence for the ecological sustainability of the Chishui River Basin.

How relevant are local climate zones and urban climate zones for urban climate research? Dijon (France) as a case study

Global warming has obtained more and more attention because the global mean land surface temperature (LST) has increased since the late 19th century. Urban heat island (UHI) effect and its thermal environment are the most important themes in urban climatology and environment researches. One of the possible causes to UHI effect is the drastic reduction in the green space in cities. The coastal cities of southeast Fujian province is the most economically developed and densely populated areas of Fujian province, even in China, and also it is experiencing rapid urbanlization that has resulted in remarkable UHI effect, which will be sure to inference the regional and urban climate, environment, and socio-ecomomic development. In this study, MODIS data of July to August acquired from 2001 to 2007 in coastal cities of southeast Fujian province were elaborately selected out to retrieve the metrics of, land surface tempertuare, normalized difference vegetation index (NDVI) and albedo so as to investigate the intensity, the spatial-temporal pattern, the tendency of UHI effect, monitor annual changes and evaluate the UHI effect though urban radio index (URI) over the study period. Additionally, a new methodology and analysis techniques what was called Urban Thermal Environment Information TuPu(UTEITP) was introduced to detect and measure within-class changes of LST from the spatial, temporal and processes view, try to find the conversion mechanism and analyze the relationship between LST, albedo and NDVI qualitatively. Morever, a correlation model was built to quantitatively analyze and better understanding the relationships between LST and NDVI, LST and albedo.The results showed that UHI effect was keeping on strengthening during the whole study period with a increase tendency overall.UTEITP provided a systematic and effective way to derive comparable changes and processes. Our analysis based on UTEITP and correlation model indicates that there was a linear relationship among surface temperature, NDVI and albedo for all study years, whereas the relationship between LST and NDVI was negative, but positive correlation was shown between NDVI and albedo. These result evidence reminds us to take some instructive measures to weaken the effect of urban heat island, improve the city's thermal and habitat environment and urban sustainable development.

Assessing the urban heat island effect of different local climate zones in Guangzhou, China

Air temperature is a pivotal indicator in urban heat island research. With the development of urbanization, the urban environment is deteriorating. The most notable phenomenon is the formation and enhancement of urban heat island. Urban heat islands are ubiquitous in metropolitan area around the world. Japan, as a developed country, is also affected by urban heat islands. This chapter introduced a temperature spatial downscaling method based on machine learning algorithm to downscale air temperature from 1 km to 250 m for high-resolution atmosphere urban heat island analysis. The core of this downscaling method is to establish the regression model between urban structure and temperature, and then we used the unchanged characteristics of regression models at different scale to predict high-resolution temperature data with high-resolution resolution urban structure, thereby analyzing atmosphere urban heat island.KeywordsUrban environmentMachine learningUrban heat island

Revealing the response of urban heat island effect to water body evaporation from main urban and suburb areas

Thermal imagery is widely used to quantify land surface temperatures to monitor the spatial extent and thermal intensity of the urban heat island (UHI) effect. Previous research has applied Landsat images, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images, Moderate Resolution Imaging Spectroradiometer (MODIS) images, and other coarse- to medium-resolution remotely sensed imagery to estimate surface temperature. These data are frequently correlated with vegetation, impervious surfaces, and temperature to quantify the drivers of the UHI effect. Because of the coarse- to medium-resolution of the thermal imagery, researchers are unable to correlate these temperature data with the more generally available high-resolution land cover classification, which are derived from high-resolution multispectral imagery. The development of advanced thermal sensors with very high-resolution thermal imagery such as the MODIS/ASTER airborne simulator (MASTER) has investigators quantifying the relationship between detailed land cover and land surface temperature. While this is an obvious next step, the published literature, i.e., the MASTER data, are often used to discriminate burned areas, assess fire severity, and classify urban land cover. Considerably less attention is given to use MASTER data in the UHI research. We demonstrate here that MASTER data in combination with high-resolution multispectral data has made it possible to monitor and model the relationship between temperature and detailed land cover such as building rooftops, residential street pavements, and parcel-based landscaping. Here, we report on data sources to conduct this type of UHI research and endeavor to intrigue researchers and scientists such that high-resolution airborne thermal imagery is used to further explore the UHI effect.