Urban tree design approaches for mitigating daytime urban heat island effects in a high-density urban environment

2016 ◽  
Vol 114 ◽  
pp. 265-274 ◽  
Author(s):  
Zheng Tan ◽  
Kevin Ka-Lun Lau ◽  
Edward Ng
Keyword(s):  
Urban Heat Island ◽  
Urban Environment ◽  
High Density ◽  
Heat Island ◽  
Urban Tree ◽  
Urban Heat

scholarly journals Statistical modelling of spatial patterns of the urban heat island intensity in the urban environment of Augsburg, Germany

Urban Climate ◽  
2019 ◽  
Vol 29 ◽  
pp. 100491 ◽  
Author(s):  
Annette Straub ◽  
Katja Berger ◽  
Susanne Breitner ◽  
Josef Cyrys ◽  
Uta Geruschkat ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Urban Environment ◽  
Spatial Patterns ◽  
Statistical Modelling ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Urban Heat

scholarly journals Spatiotemporal Changes in the Urban Heat Island Intensity of Distinct Local Climate Zones: Case Study of Zhongshan District, Dalian, China

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jun Han ◽  
Jiatong Liu ◽  
Liang Liu ◽  
Yuanzhi Ye
Keyword(s):  
Urban Heat Island ◽  
High Density ◽  
Urban Heat Island Intensity ◽  
Low Density ◽  
Heat Island ◽  
Climate Zones ◽  
Local Climate ◽  
Island Effect ◽  
Local Climate Zones ◽  
Urban Heat

Intensified due to rapid urbanization and global warming-induced high temperature extremes, the urban heat island effect has become a major environmental concern for urban residents. Scientific methods used to calculate the urban heat island intensity (UHII) and its alleviation have become urgent requirements for urban development. This study is carried out in Zhongshan District, Dalian City, which has a total area of 43.85 km2 and a 27.5 km-long coastline. The mono-window algorithm was used to retrieve the land surface temperatures (LSTs), employing Landsat remote sensing images, meteorological data, and building data from 2003, 2008, 2013, and 2019. In addition, the district was divided into local climate zones (LCZs) based on the estimated intensities and spatiotemporal variations of the heat island effect. The results show that, from 2003 to 2019, LCZs A and D shrank by 3.225 km2 and 0.395 km2, respectively, whereas LCZs B, C, and 1–6 expanded by 0.932 km2, 0.632 km2, and 2.056 km2, respectively. During this period, the maximum and minimum LSTs in Zhongshan increased by 1.365°C and 1.104°C, respectively. The LST and UHII levels of all LCZs peaked in 2019. The average LSTs of LCZs A–C increased by 1.610°C, 0.880°C, and 3.830°C, respectively, and those of LCZs 1–6 increased by 2°C–4°C. The UHIIs of LCZs A, C, and D increased by 0.730, 2.950, and 0.344, respectively, and those of LCZs 1–6 increased from 1.370–2.977 to 3.744–5.379. Overall, the regions with high LSTs are spatiotemporally correlated with high building densities. In this study, the land cover was then classified into four types (LCZs A–D) using visual interpretation and object-oriented classification, including forested land, low vegetation, bare ground, and water. Besides, the buildings were categorized as LCZs 1–6, which, respectively, represented low-density low-rises buildings, low-density high-rises buildings, low-density super high-rises buildings, high-density low-rises buildings, high-density high-rises buildings, and high-density super high-rises buildings.

scholarly journals COMPARATIVE ANALYSIS OF SURFACE URBAN HEAT ISLAND EFFECT OF ROOFTOPS AND STREETSCAPES IN CENTRAL SYDNEY

2015 ◽  
Vol 9 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Ehsan Sharifi ◽  
Steffen Lehmann
Keyword(s):  
Urban Heat Island ◽  
Open Space ◽  
High Density ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Street Network ◽  
Urban Greenery ◽  
Urban Heat ◽  
Artificial Heat ◽  
Space Ratio

Cities are frequently experiencing artificial heat stress, known as the Urban Heat Island (UHI) effect. The UHI effect is commonly present in cities due to increased urbanization, where anthropogenic heat and human modifications have altered the characteristics of surfaces and atmosphere. Urban structure, land cover and metabolism are underlined as UHI key contributors and can result in higher urban densities being up to 10°C hotter compared to their peri-urban surroundings. The UHI effect increases the health-risk of spending time outdoors and boosts the need for energy consumption, particularly for air-conditioning during summer. Under investigation is what urban features are more resilient to the surface layer Urban Heat Island (sUHI) effect in precinct scale. In the context of Sydney, this ongoing research aims to explore the most heat resilient urban features at precinct scale. This UHI investigation covers five high-density precincts in central Sydney and is based on a nocturnal remote-sensing thermal image of central Sydney taken on 6 February 2009. Comparing the surface temperature of streetscapes and buildings’ rooftops (dominant urban horizontal surfaces), indicates that open spaces and particularly streetscapes are the most sensitive urban elements to the sUHI effect. The correlations between street network intensity, open space ratio, urban greenery ratio and the sUHI effect is being analysed in Sydney’s high-density precincts. Results indicate that higher open space ratio and street network intensity correlate significantly to higher sUHI effect at precinct scale. Meanwhile, 10% increase in the urban greenery can effectively decrease the precinct temperature by 0.6°C.

scholarly journals Multi-model comparison of urban heat island modelling approaches

2018 ◽  
Vol 18 (14) ◽  
pp. 10655-10674 ◽  
Author(s):  
Jan Karlický ◽  
Peter Huszár ◽  
Tomáš Halenka ◽  
Michal Belda ◽  
Michal Žák ◽  
...  
Keyword(s):  
Wind Speed ◽  
Urban Heat Island ◽  
Urban Environment ◽  
Model Comparison ◽  
Climate Model ◽  
Heat Island ◽  
Significant Difference ◽  
Urban Heat ◽  
Urban Parameterizations ◽  
The Impact

Abstract. Cities are characterized by different physical properties of surface compared to their rural counterparts, resulting in a specific regime of the meteorological phenomenon. Our study aims to evaluate the impact of typical urban surfaces on the central European urban climate in several model simulations, performed with the Weather Research and Forecasting (WRF) model and Regional Climate Model (RegCM). The specific processes occurring in the typical urban environment are described in the models by various types of urban parameterizations, greatly differing in complexity. Our results show that all models and urban parameterizations are able to reproduce the most typical urban effect, the summer evening and nocturnal urban heat island, with the average magnitude of 2–3 °C. The impact of cities on the wind is clearly dependent on the urban parameterization employed, with more simple ones unable to fully capture the wind speed reduction induced by the city. In the summer, a significant difference in the boundary-layer height (about 25 %) between models is detected. The urban-induced changes of temperature and wind speed are propagated into higher altitudes up to 2 km, with a decreasing tendency of their magnitudes. With the exception of the daytime in the summer, the urban environment improves the weather conditions a little with regard to the pollutant dispersion, which could lead to the partly decreased concentration of the primary pollutants.

scholarly journals Effects of Climate and the Urban Heat Island Effect on Urban Tree Growth in Houston

2017 ◽  
Vol 07 (04) ◽  
pp. 428-445 ◽  
Author(s):  
Astrid Moser ◽  
Enno Uhl ◽  
Thomas Rötzer ◽  
Peter Biber ◽  
Jens Dahlhausen ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Tree Growth ◽  
Urban Heat Island Effect ◽  
Heat Island ◽  
Urban Tree ◽  
Island Effect ◽  
Urban Heat

scholarly journals How the urban environment affects the microclimate and the building energy demand for the City of Rome

2019 ◽  
Vol 23 (Suppl. 4) ◽  
pp. 1035-1042 ◽  
Author(s):  
Andrea Vallati ◽  
Luca Mauri ◽  
Chiara Colucci
Keyword(s):  
Urban Heat Island ◽  
Urban Environment ◽  
Urban Area ◽  
Air Temperature ◽  
Energy Demand ◽  
The Other ◽  
Weather Data ◽  
Heat Island ◽  
Urban Heat ◽  
The City

Urban heat island has significant impacts on buildings? energy consumption. The phenomenon is associated with increased urban air temperatures compared to the air temperature of the surrounding rural or suburban areas. The ambient air temperature growth due to climate changes and the urban heat island phenomenon are dramatically increasing the cooling demand in buildings. This is worsened by irradiation conditions, construction technologies, and subjective comfort expectations. This paper examines the impact of the urban environment on the energy demand of buildings, considering the case of two districts of the city of Rome, Italy: one is representative of a central zone, the other of a rural zone. Weather data were then used to calculate the thermal demand of a typical Italian building, ideally located in the monitored areas of the city. Standalone building with modified weather file was modeled in TRNSYS. Results show that urban heat island intensity causes an increase in cooling demand up to +33% for the urban area (+20% for the rural area) compared to the demand calculated using weather data from airportual areas. On the other hand, urban heat island intensity has a positive effect on heating demand which turns out to decrease up to -32% for the urban area (-14% for the rural area).

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