Separate and combined effects of 3D building features and urban green space on land surface temperature

Effects of landscape on thermal livability at the community scale based on fine-grained geographic information: A case study of Shenzhen

In the current research, the question of how to modify the microclimate through landscape planning to create a livable thermal environment within a residential community area has not been clarified. Therefore, this study investigated the effects of landscape on thermal livability in 2980 communities in Shenzhen, and obtained the following findings: (1) the proportion of trees and the average building height were key indicators to determine the average land surface temperature (LST) of a community, while the two-dimensional building characteristics, particularly shape, similarity, and patch dominance, were mainly responsible for regulating the spatial distribution of LST within a community; (2) at the community scale, the cooling intensity of buildings was strongest when their average height was around 40-60 m, and cooling effect of trees was most pronounced when their proportion achieved 20 %; and (3) the LST threshold for thermal livability in Shenzhen was around 35 °C. In summer, a higher proportion of trees and grass, as well as buildings with higher average heights, larger volume ratios, and more complex three-dimensional structures were favorable to maintain a livable community thermal environment, while in winter, a lower proportion of trees was more encouraged. In addition, a smaller average sky view factor can achieve a community thermal environment that warm in winter and cool in summer. These results are expected to facilitate urban planners to develop community renewal from the perspective of thermal livability.

Exploring the relationship between seasonal variations of land surface temperature and urban morphological factors in complex urban areas

The urban heat island effect is an increasingly serious problem in urban areas. Previous studies suggest that spatial variation in the urban land surface temperature (LST) is determined by interactions among urban morphological factors, but few studies have explored the main factors that affect the LST in different seasons in complex urban areas, especially at a fine scale. By considering the central Chinese city of Jinan as an example, we selected 19 parameters related to the architectural morphological factors, ecological basis factors, and humanistic factors and explored their effects on the LST in different seasons. A correlation model was used to identify the key factors and to analyze the main impact thresholds in different seasons. In the four seasons, the 19 factors all had significant correlations with LST. In particular, architectural morphological factors comprising the average building height and high building ratio had significant negative correlations with the LST in the four seasons. The architectural morphological factors comprising the floor area ratio, spatial concentration degree, building volume density, and urban surface pattern index comprising the mean nearest neighbor distance to green land, as well as humanistic factors comprising the point of interest density, nighttime light intensity, and human activity intensity of land surface had significant positive correlations with LST in the summer and autumn. Ecological basis factors made the main contributions to the LST in the spring, summer, and winter, whereas humanistic factors contributed the most in the autumn. The contributions of architectural morphological factors were relatively low in the four seasons. The dominant factors differed in each season but their thresholds had similar characteristics. The results obtained in this study deepen our understanding of the relationships between urban morphology and the urban heat island effect, and provide practical suggestions for improving the urban thermal environment through reasonable building planning and management.

Digital economy and environmental governance performance: empirical evidence from 275 cities in China

Along with the steady worsening of environmental contamination, improving environmental governance performance (EGP) is an urgent issue that needs to be addressed. This study adopts panel data from 275 Chinese cities to examine the holistic relationship between the digital economy (DE) and urban EGP in multiple dimensions. The relationship is tested using fixed-effects models, mediated effects models, panel threshold models, and the spatial Durbin models. Results indicated that (1) the DE can effectively improve urban EGP. The findings still hold after robustness tests using instrumental variable estimation and the introduction of exogenous policy shocks. (2) The analysis of mediating effects shows that green technology innovation and industrial structure optimization are critical transmissions. (3) The panel threshold regression results indicate a nonlinear incremental phenomenon of the significant impact of the DE on urban EGP when nighttime lighting data is used as the threshold. (4) Spatial spillover analysis shows a positive spatial spillover effect of DE development on EGP in the surrounding cities. (5) Spatial heterogeneity analysis states that the enhancement effect of DE development on EGP is more significant in eastern China. Furthermore, areas located within urban agglomerations are more influenced by the DE. These findings provide a policy reference for fully exploiting the environmental enhancement effects of the DE.

Influence of built environment on building energy consumption: a case study in Nanjing, China

Built environment plays a significant role in optimizing building energy consumption. However, few studies have explored the comprehensive effect between built environment metrics on building energy consumption. Thus, this study aims to explore interrelationships between built environment on building energy consumption focused on moderating effect. In this study, we established a built environment measure system from the perspective of land use and land cover, landscape structure and building configuration. This study explored the correlation between built environment and building energy consumption and analyzed the moderating effect of building configuration emphatically. Results show that: for integrated grids group, normalized difference vegetation index (NDVI) and modified normalized difference water index (MNDWI) have a positive influence and impervious area (IA) has a negative influence, with NDVI has the greatest impact. Building floor (BF), building coverage ratio (BCR) and aspect ratio can weaken the positive relationship between NDVI and energy use intensity of grid ( EUI grid ). BCR weakens the positive effect of MNDWI on EUI grid . The moderating effect of building configuration on EUI varies in the same grid group and among different grid groups. For sample 1, BCR inhibits the negative effect of mean perimeter-area ration (PARA-MN) on EUI grid . For sample 2, BF promotes the negative effect of number of patches and land use richness index (R) on EUI grid . And sky view factor inhibits the positive effect of IA on EUI grid . This study reveals the pathways of built environment on building energy consumption. As a result, the keys of optimizing building energy consumption are the reasonable planning and optimization of the urban built environment of different land cover.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10668-023-02930-w.

Dominance of Influencing Factors on Cooling Effect of Urban Parks in Different Climatic Regions

The enhancement of the park cooling effect (PCE) is one method used to alleviate the urban heat island (UHI). The cooling effect is affected by park factors; however, the importance of these factors in the case of the PCE is still unclear. Optimizing or planning urban parks according to the importance of the influencing factors can effectively enhance the PCE. Herein, we selected 502 urban parks in 29 cities in China with three different climatic regions and quantified the PCE based on the park cooling intensity (PCI) and park cooling area (PCA). Subsequently, the relative importance of the influencing factors for the PCE was compared to identify the main factors. Consequently, certain park planning suggestions were proposed to enhance the cooling effect. The results show that: (1) the PCE increased in the order of arid/semi-arid, semi-humid, and humid regions. (2) The main factors of the PCI differed significantly in different climatic regions; however, the waterbody within a park significantly affected the PCI in all three climates. However, for the PCA, park patch characteristics were the dominant factor, contributing approximately 80% in the three climates regions. (3) In arid/semi-arid and semi-humid regions, the optimal area proportion of waterbody and vegetation within the park were approximately 1:2 and 1:1, respectively, and the threshold value of the park area was 16 ha. In contrast, in the humid region, the addition of a waterbody area within the park, to the best extent possible, enhanced the PCI, and the threshold value of the park area was 19 ha. The unique results of this study are expected to function as a guide to future urban park planning on a regional scale to maximize ecological benefits while mitigating the UHI.

Biodiversity in Urban Green Space: A Bibliometric Review on the Current Research Field and Its Prospects

Understanding the development process of urban green space and biodiversity conservation strategies in urban green space is vital for sustainable urban development. However, a systematic review of the urban green space biodiversity research is still lacking. We have retrieved 3806 articles in WOS core journals and carried out the bibliometrics analysis through the three related search terms: urban, green space, and biodiversity. We found that: (1) the year 2009 was a changing point, and the number of articles have increased exponentially since 2009. The United States, China, Europe, and Australia are closely linked, and four research centers have formed; (2) all studies can be classified into three research themes: "Pattern of Urban Green Biodiversity", "Ecological Function of Urban Green Biodiversity", and "Sustainability of Urban Green Biodiversity"; (3) based on the evolution of keywords, this field is divided into the budding stage (1998-2012) and the development stage (2012-2021). The keywords in the budding stage focus on the diversity of different species, and the keywords in the development stage focus on the ecosystem services, biodiversity protection, and residents' satisfaction; (4) the future research focus may be in three aspects: studies on green space in the less urbanized area and urban-rural ecotone, the regulation mechanism and cultural services of urban green space, and the rational layout and management of urban green space. This study hopes to provide a reference for future research on urban green space biodiversity and promote the sustainable development of urban green space.

Emerging paradigm shift in urban indicators: Integration of the vertical dimension

Since new urbanism strategies encourage higher density and compact city development, it is expected that the height of urban environments will increase in the next few years as a remedy for many urban problems such as urban sprawl, cost of living, and detrimental environmental impacts of horizontal development of cities. Therefore, urban designers and planners should consider the third dimension of cities according to the vertical growth paradigm that is inherently a three-dimensional (3D) socioeconomic and environmental process. While a large body of literature is focusing on horizontal or two-dimensional (2D) urban indicators, it still lacks more research to compare 2D and 3D urban indicators. In this study, urban environment quality indicators, as a prominent example of urban indicators, were measured in two and three dimensions in the central business district of Urmia in Iran. Also, a Pearson's correlation analysis was performed to find a pairwise relationship between indicators. The results of the correlation analysis revealed that most 3D indicators have no significant linear relationship with other indicators, so predicting 3D indicator values based on other indicators is a difficult or even impossible task. Comparing 2D indicators with 3D ones shows that approximately 30 percent of the study area has a different urban environmental quality if it integrates the vertical dimension with 2D indicators. In addition, measuring and modelling 3D indicators provide better locational information on urban conditions and the life of citizens than traditional 2D urban indicators. This study recommends planning for the expansion of 3D information and associated tools that lead to deeper analytical insights into 3D Urban Environmental Quality assessment.

Seasonal Contrast and Interactive Effects of Potential Drivers on Land Surface Temperature in the Sichuan Basin, China

Little is known about the seasonal heterogeneity of land surface temperature (LST) and the interaction relationship between potential drivers in Sichuan Basin, China. In this study, based on exploring the spatial heterogeneity of LST in Sichuan Basin, China, multi-source remote sensing data as potential drivers were selected and a Geo-detector model was applied to analyze the main drivers and the interactive relationship between drivers on LST during different seasons. The results showed that the high-temperature areas in Sichuan Basin in different seasons all appeared in the cities near the high mountains on the edge of the basin. This phenomenon was summarized as “sinking heat island” by us. From the driving factors, the biophysical parameters (DEM, SLOPE and NDVI) had the greatest impact on LST in each season, reaching the peak in the transition season. The climate parameters (WIND, HUM, PRE and TEM) and socioeconomic parameters (LIGHT, POP and ROAD) also had a certain impact on LST. The influence of a single landscape parameter (SHDI, PD, LPI, ED and LSI) on LST is limited. From the effect of factor interaction on LST, the interaction of biophysical parameters, climatic parameters and landscape parameters from summer to the transitional season was strengthened obviously, and it showed a downward trend in the winter; in contrast, the socioeconomic parameters showed the opposite characteristics, indicating that the interaction between human activities and other factors affected LST more obviously in the winter. The results of this study are not only valuable for understanding the spatial features of LST but also important for formulating mitigation strategies and sustainable development of urban heat island in Sichuan Basin.

Effect of Land Surface Temperature on Urban Heat Island in Varanasi City, India

Crucial changes in urban climate can be witnessed due to rapid urbanisation of cities across the world. It is important to find a balance between urban expansion and thermal environment quality to guarantee sustainable urban development. Thus, it is a major research priority to study the urban heat island (UHI) in various fields, i.e., climate change urban ecology, urban climatology, urban planning, mitigation and management, urban geography, etc. The present study highlighted the interrelationship between land surface temperature (LST) and the abundance of impervious cover and green cover in the Varanasi city of Uttar Pradesh, India. For this purpose, we used various GIS and remote-sensing techniques. Landsat 8 images, land-use–land-cover pattern including urban/rural gradients, and grid- and metric-based multi-resolution techniques were used for the analysis. From the study, it was noticed that LST, density of impervious cover, and density of green cover were correlated significantly, and an urban gradient existed over the entire city, depicting a typical UHI profile. It was also concluded that the orientation, randomness, and aggregation of impervious cover and green cover have a strong correlation with LST. From this study, it is recommended that, when planning urban extension, spatial variation of impervious cover and green cover are designed properly to ensure the comfort of all living beings as per the ecological point of view.