scholarly journals Thermal and Humidity Effect of Urban Green Spaces with Different Shapes: A Case Study of Shanghai, China

2021 ◽  
Vol 18 (11) ◽  
pp. 5941
Author(s):  
Hongyu Du ◽  
Fengqi Zhou ◽  
Wenbo Cai ◽  
Yongli Cai ◽  
Yanqing Xu
Keyword(s):  
Field Measurements ◽  
Shape Index ◽  
Green Spaces ◽  
Humidity Effect ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Positive Effects ◽  
Human Thermal Comfort ◽  
Comfort Levels ◽  
Humidity Index

Research shows that urban green spaces (UGSs) provide a number of positive effects, including enhancing human thermal comfort levels by decreasing air temperature (AT) and increasing relative humidity (RH). However, research on how the shape of an UGS influences these effects is yet to be explored. This paper explores the principles and features behind this. The AT and RH surrounding an UGS within a horizontal scale of 20 m was explored. Microclimate field measurements around 35 UGSs in Shanghai, China were carried out. The samples covered the most applied types of UGSs—punctiform, linear, and planar. Comparison spots were selected away from the sampled UGSs. The effects were studied by data collection and statistical analysis. The results indicate that the shape of the UGS had significant impact on the Temperature Humidity Index (THI). In the summer, the amplitude of THI variation decreases with the distance to UGS. For punctiform UGS, a larger total area and existence of water body results in a lower THI. A wider, linear UGS with the same orientation as the direction of the prevailing wind contributes more to decrease the surrounding THI. The total area of planar UGS is not critical. A higher landscape shape index of a planar UGS is the critical point to achieve a lower THI. The results can serve as a reference when planning and designing future UGSs.

scholarly journals Evaluating the Cooling Potential of Urban Green Spaces to Tackle Urban Climate Change in Lisbon

2019 ◽  
Vol 11 (9) ◽  
pp. 2480 ◽  
Author(s):  
Cláudia Reis ◽  
António Lopes
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Urban Climate ◽  
Green Spaces ◽  
Reference Station ◽  
Future Climate Change ◽  
Measuring Point ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Human Thermal Comfort

The increase and optimization of urban vegetation has been considered an effective mitigation measure of an urban heat island (UHI), with positive effects on human thermal comfort. In this study, the cooling potential of all green spaces in Lisbon was estimated. For that, several mobile measurements of air temperature data were made in a single park (Gulbenkian’s Garden). These measurements were used for the interpolation of air temperature. Furthermore, urban biomass was estimated using remote sensing products, namely Landsat satellite images. Ultimately, a linear regression model was built from the relation between vegetation density and air temperature. Results regarding the estimation of biomass (AGB) in the city of Lisbon were higher in winter than in summer. The urban green spaces cooling potential model showed that for every decrease of 1 °C in air temperature between a measuring point and a reference station we need to increase the area covered by vegetation by 50 m2 (planar measure). This methodology can be applied in other urban areas for the quantification of the cooling effect provided by vegetation in order to improve urban climate thermal conditions and human well-being and, consequently, to mitigate some consequences of future climate change.

scholarly journals Impact of Frequency of Visits and Time Spent in Urban Green Space on Subjective Well-Being

2019 ◽  
Vol 11 (15) ◽  
pp. 4189 ◽  
Author(s):  
Sung-Kwon Hong ◽  
Sang-Woo Lee ◽  
Hyun-Kil Jo ◽  
Miyeon Yoo
Keyword(s):  
Structural Equation ◽  
Structural Equation Models ◽  
Well Being ◽  
Green Spaces ◽  
Subjective Well Being ◽  
Negative Effects ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Positive Effects ◽  
Visit Frequency

Exposure to green spaces can reduce the negative effects of stress. This study examines how frequency of visits and time spent in urban green spaces (UGS) affect urban dwellers’ subjective well-being. We also investigated the numbers of respondents visiting UGS, their primary motivation, and constraints on their ability to visit. Using quota sampling, an online survey was conducted of 400 residents of Daejeon City, South Korea. ANOVA results indicated no significant interactions between visit frequency and time spent in UGS. Respondents who had visited UGS within the past two weeks expressed higher positive and lower negative emotions than did non-visitors, regardless of visit frequency, and regular visitors showed higher general life satisfaction levels. These positive effects were confirmed by estimated structural equation models. However, the time spent in UGS did not affect emotions or life satisfaction in general. Heavy users mostly visited UGS to walk, and light/non-users cited the lack of urban green spaces near their home as the major constraint on visiting UGS. The estimated structural equation models clearly show positive effects from motivation and negative effects of constraints and access time to UGS on visit frequency. To improve urban dwellers’ subjective well-being, UGS should prioritize good walking environments and accessibility.

scholarly journals Urban Green Space Fragmentation and Urbanization: A Spatiotemporal Perspective

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 333 ◽  
Author(s):  
Fangzheng Li ◽  
Wei Zheng ◽  
Yu Wang ◽  
Junhui Liang ◽  
Shuang Xie ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Shape Index ◽  
Green Spaces ◽  
Rapid Urbanization ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Geographically Weighted Regression Model ◽  
Nighttime Light Data ◽  
Green Areas ◽  
High Level

Urbanization leads to the occupation of green areas, directly contributing to a high level of fragmentation of urban green spaces, which, in turn, results in numerous socioeconomic and environmental problems. Consequently, an understanding of the relationships between patterns of urban green spaces and urbanization processes is essential. Although previous quantitative studies have examined this relationship, they have not included an exploration of spatial heterogeneities in the effects of urbanization on the spatial patterns of urban green areas. We therefore applied a spatiotemporal perspective to examine the above relationship, while considering the wider planning context. First, we quantified the extent of fragmentation of urban green spaces using landscape metrics comprising the largest patch index (LPI) and landscape shape index (LSI). Next, using the calculated spatial metrics and nighttime light data (NTL) for central Beijing for the period 1992–2016, we applied a geographically weighted regression model to assess variations in the spatiotemporal effects of urbanization on the fragmentation of urban green spaces. The results showed that urbanization initially occurred mainly in the northern parts of Beijing, whereas urbanization of southern urban fringe areas occurred after 2008. The reduction in green spaces along with increasing fragmentation and complex spatial patterns are indicative of issues relating to Beijing’s rapid urbanization and planning policies. This study contributes to an understanding of how urbanization influences fragmentation of urban green spaces and offers insights for the planning of urban green spaces from the perspective of promoting sustainability.

scholarly journals Importance Evaluation Based on Random Forest Algorithms: Insights into the Relationship between Negative Air Ions Variability and Environmental Factors in Urban Green Spaces

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 706
Author(s):  
Linghao Luo ◽  
Wen Sun ◽  
Yujie Han ◽  
Wenwen Zhang ◽  
Chunjiang Liu ◽  
...  
Keyword(s):  
Random Forest ◽  
Environmental Factors ◽  
Green Spaces ◽  
Stable Range ◽  
Air Ions ◽  
Large Variability ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Positive Effects ◽  
Negative Air Ions

Negative air ions (NAIs) exert positive effects on human health. Urban green spaces produce NAIs and perform valuable ecological functions; this phenomenon has attracted much attention. However, NAIs in urban green spaces are influenced by many factors, leading to extremely large variability in their concentrations and complicating their measurement. Therefore, we collected observational data on NAI concentrations (NAICs), as well as on other environmental factors for one year in Shanghai City Park. We then used this data to construct an indicator of NAI variability (NAIV); we understand NAIV to be dependent upon NAIC, and study of the derivative can better reflect the driving force and dominant factors of the original function. Based on a preliminary investigation of correlation, and on a multiple linear regression analysis, we used a random forest algorithm to evaluate the influence of various factors that affect the variability of NAIs. The results show that “water factors,” whose main contribution is humidity, exert the most influence, followed by “phenology factors,” whose main contribution is temperature, and “particulate factors,” whose main contribution is PM2.5. High humidity, high temperature, and low PM2.5 concentration enrich NAI generation and extend their lifetimes, thus helping to maintain them within a relatively stable range. In this study, the main driving forces that govern NAI changes were shown to be humidity, temperature and particulate matter. Our results may help to deepen our understanding of NAI characteristics and applications in urban green spaces.

scholarly journals What Characteristics of Urban Green Spaces and Recreational Activities Do Self-Reported Stressed Individuals Like? A Case Study of Baoji, China

2019 ◽  
Vol 16 (8) ◽  
pp. 1348 ◽  
Author(s):  
Tian Gao ◽  
Rui Song ◽  
Ling Zhu ◽  
Ling Qiu
Keyword(s):  
Green Space ◽  
Leisure Activities ◽  
Green Spaces ◽  
Stress Recovery ◽  
Human Beings ◽  
Social Dimensions ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Positive Effects ◽  
Restorative Environment

Several studies have revealed the positive effects of green space and certain activities on counteracting the physical and mental pressure felt by human beings. However, how self-reported stressed people perceive restorative green spaces, their preferences for specific characteristics and activities, and what characteristics of urban green space can induce various types of activities for stress recovery has not been fully examined in the high-density cities of China. Using an on-site questionnaire survey conducted in the People’s Park (PP) in Baoji, China, this study is the first to consider the relationship among eight sensory dimensions, activity types and stress recovery in Chinese green space. Results showed that the highest-stressed respondents were more likely to spend their time in multi-layered woodlands adjacent to water, with more experiences of serene but less about prospect. They preferred serene dimension more, while the culture and social dimensions were least preferred. Sports and leisure activities and quiet activities were the most popular among highest-stressed respondents, which were positively related to the serene and nature dimensions, respectively. Results suggested that the most restorative environment for stress recovery can be regarded as multi-layered woodlands adjacent to water with more serene and nature, less prospect and few or no culture and social dimensions.

scholarly journals Dynamic Cooling Effects of Permanent Urban Green Spaces in Beijing, China

2021 ◽  
Vol 13 (16) ◽  
pp. 3282
Author(s):  
Jiacheng Zhao ◽  
Xiang Zhao ◽  
Shunlin Liang ◽  
Haoyu Wang ◽  
Naijing Liu ◽  
...  
Keyword(s):  
Time Series Data ◽  
Temporal Dynamics ◽  
Critical Role ◽  
Green Spaces ◽  
Series Data ◽  
Surface Cooling ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Human Thermal Comfort ◽  
Cooling Effects

Urban green spaces (UGSs) play a critical role in human thermal comfort, energy consumption and urban ecology. Although the heat mitigation capability of UGSs has been frequently reported, many of the current understandings are based on short-term observations, and the long-term temporal dynamics of UGS cooling effects are still lacking. This gap may cause over- or underestimation and largely ignores how the cooling effects change with climate change and urban growth. Accordingly, we used Landsat-based time series data to analyze the changes in permanent UGS greenness, surface-cooling effects and their biophysical responses in Beijing in the past 40 years (1984–2020). The results demonstrate segmented changes in UGS surface cooling that were mainly linked to the responses of canopy transpiration and albedo to vegetation conditions. During a rapid greening of UGSs in the recent two decades, transpiration cooling dominated albedo-induced warming to provide a discernable cooling enhancement. In addition, such enhancement showed seasonal differences ranging from less than 1 °C to more than 2 °C, and the most evident enhancement occurred on summer days (~2.4 °C) when vegetation is most needed to provide cooling. The highlighted dynamics of UGSs help urban planners better balance the maintenance costs and the environmental gains for UGS management.

scholarly journals The Socioeconomic Welfare of Urban Green Areas and Parks; A Literature Review of Available Evidence

2021 ◽  
Vol 13 (14) ◽  
pp. 7863
Author(s):  
Antonios Kolimenakis ◽  
Alexandra D. Solomou ◽  
Nikolaos Proutsos ◽  
Evangelia V. Avramidou ◽  
Evangelia Korakaki ◽  
...  
Keyword(s):  
Literature Review ◽  
Urban Policy ◽  
Green Spaces ◽  
Future Research ◽  
Natural Environments ◽  
Exclusion Criteria ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Urban Green Areas ◽  
Green Areas

Urban green areas present a lucid example for the harmonious co-existence of the artificial and natural environments best illustrated by their interdependence and interconnection in urban spaces. Urban green areas are essential for the health and wellbeing of citizens. The present study aimed to investigate those multiple benefits for citizens that arise through the existence of urban green areas, as well as important policy dimensions that should be considered when designing the expansion of urban green spaces in urban development. The study was based on a literature review to examine for available evidence on the benefit levels derived by the existence of urban green areas. An extended literature review was followed by a structured review, based on specific inclusion and exclusion criteria, which partly followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search was conducted in two databases, and a total of 1674 articles and abstracts were identified through the database searches. After removing 114 duplicates, 1560 records were initially screened based on title and abstract. Following inclusion and exclusion criteria, 14 articles were incorporated in the structured review and a total of 47 in the extended review. The extended literature review identified 33 additional articles examining aspects of benefits that did not fall under the pre-established inclusion and exclusion criteria used in the structured review, such as health benefits and other social parameters associated with urban green spaces. The selected studies were allocated in five principal groups according to study types: three of the them consisted of studies employing “willingness to pay” (WTP) methods, five were based on property values, two studies assigned monetary values, while another two assigned CO2 values, and, finally, two studies were based on qualitative criteria. The results indicated benefits to citizens and increased welfare levels gained by the existence of urban green areas. The conducted review revealed a number of findings and recommendations that could direct future research and urban policy. Those hints could assist local authorities as well as stakeholders in order to measure and assess the benefits of green spaces and urban parks and promote measures and programs to assist their further deployment.

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