Urban Heat Island Effect of Addis Ababa City: Implications of Urban Green Spaces for Climate Change Adaptation

2017 ◽  
pp. 539-552 ◽  
Author(s):  
Ermias Teferi ◽  
Hiwot Abraha
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Climate Change Adaptation ◽  
Addis Ababa ◽  
Green Spaces ◽  
Heat Island ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Island Effect ◽  
Urban Heat

Quantifying the effects of urban vegetation on water partitioning in complex cityscapes: the potential of isotope-based ecohydrological models

2020 ◽  
Author(s):  
Mikael Gillefalk ◽  
Dörthe Tetzlaff ◽  
Reinhard Hinkelmann ◽  
Lena-Marie Kuhlemann ◽  
Aaron Smith ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Groundwater Recharge ◽  
Water Use ◽  
Green Spaces ◽  
Heat Island ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Island Effect ◽  
Water Partitioning ◽  
Urban Heat

<p>The continued global acceleration of urbanisation increasingly requires sustainable, adaptive management strategies for land and water use in cities. Although the effects of buildings and sealed surfaces on urban runoff generation (via storm drains) and local climate (through the urban heat island effect) are well known, much less is known about how these artificial influences integrate with water partitioning in more natural urban green spaces. In particular, little is quantitatively known about how different types of urban green spaces (lawns, parks, woodland etc.) regulate the partitioning of evaporation, transpiration and groundwater recharge. To address this crucial issue, we integrated field observations with advanced, isotope-based ecohydrological modelling at the plot scale in the urban area of Berlin, Germany. Measurements of soil moisture, sap flow, and stable isotopes in precipitation, soil water and groundwater have been made over the course of one growing season. Additionally, an eddy flux tower at the site Rothenburgstraße in Berlin-Steglitz continuously collects hydroclimate data by measuring temperature, precipitation, radiation, humidity and wind speed at high temporal resolution. These data (30-min averages) have been used as input to, and for calibration of, the process-based ecohydrological model EcH<sub>2</sub>O-iso. The model also tracks stable isotope ratios and water ages in various stores (e.g. soils and groundwater) and fluxes (evaporation, transpiration and recharge). EcH<sub>2</sub>O-iso has successfully been used to describe the effects of vegetation cover on water partitioning in a number of studies but this is the first implementation in an urban setting. It shows that ecohydrological water use by vegetation type increases in the order forests > shrubs > grass, mainly through higher interception and transpiration. Accordingly, trees can reduce groundwater recharge by >50%, but provide cooling latent heat transfers to the atmosphere.  Similarly, ages of stored water and fluxes are generally greater under trees than grass. The results, which form the basis for future upscaling, show that urban green spaces play an important role in urban hydrology and in Berlin there is a trade-off between moderating the urban heat island effect and maintaining groundwater recharge. Consequently, it is clear that vegetation management needs to be considered in sustainable water and land use planning in urban areas to build resilience in cities to climatic and other environmental change.</p>

scholarly journals Influence of Spatial Characteristics of Green Spaces on Microclimate: A Case Study in Suzhou Industrial Park, China

2021 ◽  
Author(s):  
Xiangdong Xiao ◽  
Lulu Zhang ◽  
Yimei Xiong
Keyword(s):  
Urban Heat Island ◽  
Green Space ◽  
Green Spaces ◽  
Medium Size ◽  
Industrial Park ◽  
Air Cooling ◽  
Heat Island ◽  
Local Cooling ◽  
Urban Green Spaces ◽  
Urban Heat

Abstract Continuous urban development leads to urban heat island effects. Research suggests that urban green spaces can help effectively reduce urban heat island effects in the summer. Previous studies have mainly focused on the influence of different underlying surfaces on air cooling and humidification. There is a lack of in-depth research on the relationship between park structure and microclimatic effects. Here, we examined the main landscape parameters of green spaces in 15 parks located in Suzhou Industrial Park (SIP) with a subtropical maritime monsoon climate zone during the summer to analyze their influence on the microclimate. The average cooling and humidifying effect of medium-size green spaces was most significant during high-temperature hours in the daytime. When the distance to a water body was the same, the average cooling and humidifying effect ranked as follows: large-size green space > small-size green space > medium-size green space. We explored the mechanisms of the local cooling and humidifying effects of woodland and water areas in parks by numerical simulations. The significance of the cooling and humidifying effects of water areas of different shapes was as follows: annular water > massive water > banded water. This confirmed that the shape and size of water areas within a green space has a significant influence on local cooling and humidification.

scholarly journals Influence of Urban Scale and Urban Expansion on the Urban Heat Island Effect in Metropolitan Areas: Case Study of Beijing–Tianjin–Hebei Urban Agglomeration

2020 ◽  
Vol 12 (21) ◽  
pp. 3491 ◽  
Author(s):  
Mingxing Chen ◽  
Yuan Zhou ◽  
Maogui Hu ◽  
Yaliu Zhou
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Urban Heat Island ◽  
Urban Expansion ◽  
Urban Agglomeration ◽  
Heat Island ◽  
Average Surface ◽  
Island Effect ◽  
Urban Heat ◽  
The Relationship

Global large-scale urbanization has a deep impact on climate change and has brought great challenges to sustainable development, especially in urban agglomerations. At present, there is still a lack of research on the quantitative assessment of the relationship between urban scale and urban expansion and the degree of the urban heat island (UHI) effect, as well as a discussion on mitigation and adaptation of the UHI effect from the perspective of planning. This paper analyzes the regional urbanization process, average surface temperature variation characteristics, surface urban heat island (SUHI), which reflects the intensity of UHI, and the relationship between urban expansion, urban scale, and the UHI in the Beijing–Tianjin–Hebei (BTH) urban agglomeration using multi-source analysis of data from 2000, 2005, 2010, and 2015. The results show that the UHI effect in the study area was significant. The average surface temperature of central areas was the highest, and decreased from central areas to suburbs in the order of central areas > expanding areas > rural residential areas. From the perspective of spatial distribution, in Beijing, the southern part of the study area, the junction of Tianjin, Langfang, and Cangzhou are areas with intense SUHI. The scale and pace of expansion of urban land in Beijing were more than in other cities, the influencing range of SUHI in Beijing increased obviously, and the SUHI of central areas was most intense. The results indicate that due to the larger urban scale of the BTH urban agglomeration, it will face a greater UHI effect. The UHI effect was also more significant in areas of dense distribution in cities within the urban agglomeration. Based on results and existing research, planning suggestions are proposed for central areas with regard to expanding urban areas and suburbs to alleviate the urban heat island effect and improve the resilience of cities to climate change.

scholarly journals The Cooling Effect of Urban Green Spaces in Metacities: A Case Study of Beijing, China’s Capital

2021 ◽  
Vol 13 (22) ◽  
pp. 4601
Author(s):  
Liang Yan ◽  
Wenxiao Jia ◽  
Shuqing Zhao
Keyword(s):  
Well Being ◽  
Green Spaces ◽  
Cooling Effect ◽  
Heat Island ◽  
Urban Green ◽  
Urban Green Spaces ◽  
Cooling Intensity ◽  
Urban Heat ◽  
Health And Well Being

Urban green spaces have many vital ecosystem services such as air cleaning, noise reduction, and carbon sequestration. Amid these great benefits from urban green spaces, the cooling effects via shading and evapotranspiration can mitigate the urban heat island effect. The impact of urban green spaces (UGSs) on the urban thermal environment in Beijing was quantified as a case study of metacities using four metrics: Land surface temperature (LST), cooling intensity, cooling extent, and cooling lapse. Three hundred and sixteen urban green spaces were extracted within the 4th ring road of Beijing from SPOT 6 satellite imagery and retrieved LST from Landsat 8 remote sensing data. The results showed that the cooling intensity of green spaces was generally more prominent in the areas with denser human activities and higher LST in this metacity. Vegetation density is always the dominant driver for the cooling effect indicated by all of the metrics. Furthermore, the results showed that those dispersive green spaces smaller than 9 ha, which are closely linked to the health and well-being of citizens, can possess about 6 °C of cooling effect variability, suggesting a great potential of managing the layout of small UGSs. In addition, the water nearby could be introduced to couple with the green and blue space for the promotion of cooling and enhancement of thermal comfort for tourists and residents. As the severe urban heating threatens human health and well-being in metacities, our findings may provide solutions for the mitigation of both the urban heat island and global climate warming of the UGS area customized cooling service.

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