Sensitivity study of the urban heat island intensity to urban characteristics

Hamdi, Rafiq; Schayes, G.

doi:10.1002/joc.1598

Cited by 117 publications

(65 citation statements)

References 34 publications

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“…The average UHI approaches zero degrees close to sunrise (between 05:00 and 06:00 h LT) and reaches the largest negative values at about 08:00 h LT. In the morning and afternoon, the average UHI gradually increases and reaches a maximum at about 18:00 h LT. A stronger UHI in the night-time hours was also found in previous studies (Hamdi & Schayes 2008. These studies suggested that the UHI disappearing after sunrise in the morning is due to the effective heat storage, shadowing and low solar radiation, which make urban areas warm up slower than rural areas.…”

Section: Uhi Intensitiessupporting

confidence: 78%

Urban impacts on air temperature and precipitation over The Netherlands

Golroudbary¹,

Zeng²,

Mannaerts³

et al. 2018

Clim. Res.

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The detection of changes in the weather of urban areas is an important issue for understanding the impact of weather on human lives. Five years of basic weather observations (2011−2015) from automatic and amateur networks across The Netherlands were used to investigate the urban effects on meteorological parameters with a focus on temperature (e.g. urban heat island [UHI]) and precipitation. Representative stations were selected based on metadata and a set of criteria for data quality control. An hourly analysis indicates that UHIs are a nocturnal phenomenon in The Netherlands and are more prominent after sunset, when they exceed 2°C. A seasonal analysis shows that UHIs occur in all seasons during the year, with the most significant UHI occurring in the summer. Furthermore, the differences in the precipitation of urban and rural areas were shown to be greatest after sunrise during the day. The maximum hourly UHI and hourly precipitation distributions were analyzed using a generalized extreme value model. The occurrences of maximum precipitation are likely to be more frequent at urban stations than at the nearby rural stations. Additionally, the distinct seasonal cycle of precipitation that is dependent on the UHI demonstrates that the maximum UHI and precipitation occurred in the summer. Our results indicate that the UHI and precipitation enhancements in Dutch urban residential areas, as obtained from the data of weather amateurs, are in agreement with the results presented in the literature, and that 7% more precipitation occurs in cities than in rural areas.

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Section: Uhi Intensitiessupporting

confidence: 78%

Urban impacts on air temperature and precipitation over The Netherlands

Golroudbary¹,

Zeng²,

Mannaerts³

et al. 2018

Clim. Res.

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“…Unfortunately, natural cooling processes of evaporation and transpiration are often much reduced in part due to vegetation replacement with impervious surfaces. Recent studies showed that urban locations with a greater percentage of vegetated area are frequently cooler, as is a city with an overall greater percentage of vegetative cover density [2,18,19]. The magnitude of the heating effect in an urban heat island is also dependent upon the georgraphical location of the city.…”

Section: Alterations To Climate Variablesmentioning

confidence: 99%

Localized Climate and Surface Energy Flux Alterations across an Urban Gradient in the Central U.S.

et al. 2014

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Long-term urban and rural climate data spanning January 1995 through October 2013 were analyzed to investigate the Urban Heat Island (UHI) effect in a representative mid-sized city of the central US. Locally distributed climate data were also collected at nested low density urban, recently developed, and high density urban monitoring sites from June through September 2013 to improve mechanistic understanding of spatial variability of the UHI effect based upon urban land use intensity. Long-term analyses (1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013) indicate significant differences (p < 0.001) between average air temperature (13.47 and 12.89 °C, at the urban and rural site respectively), relative humidity (69.11% and 72.51%, urban and rural respectively), and average wind speed (2.05 and 3.15 m/s urban and rural respectively). Significant differences (p < 0.001) between urban monitoring sites indicate an urban microclimate gradient for all climate variables except precipitation. Results of OPEN ACCESSEnergies 2014, 7 1771 analysis of net radiation and soil heat flux data suggest distinct localized alterations in urban energy budgets due to land use intensity. Study results hold important implications for urban planners and land managers seeking to improve and implement better urban management practices. Results also reinforce the need for distributed urban energy balance investigations.

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“…Numerous concepts have been developed to mitigate the heat load in urban areas, such as customizing urban vegetation for shading and evaporative cooling (Spronken-Smith and Oke 1998; Solecki et al 2005;Gill et al 2007;Memon et al 2008;Bowler et al 2010;Oliveira et al 2011;Fallmann et al 2014), introducing open water surfaces (Hathway and Sharples 2012;Theeuwes et al 2013), planning of built structures that support ventilation by choosing an appropriate geometry and size of buildings and street areas (Ali-Toudert and Mayer 2007a, b;Middel et al 2014), and applying suitable materials and colours for buildings to reduce the heat storage and the absorption of solar radiation (Hamdi and Schayes 2008;Krayenhoff and Voogt 2010;Santamouris et al 2012). Increase in vegetation and water surfaces, known as green and blue infrastructure, is of particular interest due to their multiple functionality and benefits for the urban environment, such as increasing urban biodiversity and improving air quality in case of urban vegetation (Akbari et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Modelling the potential of green and blue infrastructure to reduce urban heat load in the city of Vienna

et al. 2016

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The climate warming trend and city growth contribute to the generation of excessive heat in urban areas. This could be reduced by introducing vegetation and open water surfaces in urban design. This study evaluates the cooling efficiency of green and blue infrastructure to reduce urban heat load using a set of idealized case simulations and a real city model application for Vienna. The idealized case simulations show that the cooling effect of green and blue infrastructure is dependent on the building type, time of the day and in case of blue infrastructure, the water temperature. The temperature reduction and the size of the cooled surface are largest in densely built-up environments. The real case simulations for Vienna, which include the terrain, inhomogeneous land use distribution and observed climate data, show that urban planning measures should be applied extensively in order to gain substantial cooling on the city scale. The best efficiency can be reached by targeted implementation of minor but combined measures such as a decrease in building density of 10 %, a decrease in pavement by 20 % and an enlargement in green or water spaces by 20 %. Additionally, the modelling results show that equal heat load mitigation measures may have different efficiency dependent on location in the city due to the prevailing meteorological conditions and land use characteristics in the neighbouring environment.

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Sensitivity study of the urban heat island intensity to urban characteristics

Cited by 117 publications

References 34 publications

Urban impacts on air temperature and precipitation over The Netherlands

Urban impacts on air temperature and precipitation over The Netherlands

Localized Climate and Surface Energy Flux Alterations across an Urban Gradient in the Central U.S.

Modelling the potential of green and blue infrastructure to reduce urban heat load in the city of Vienna

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