scholarly journals Development of an operational modelling system for urban heat islands: an application to Athens, Greece

2013 ◽  
Vol 1 (5) ◽  
pp. 4963-4996
Author(s):  
T. M. Giannaros ◽  
D. Melas ◽  
I. A. Daglis ◽  
I. Keramitsoglou
Keyword(s):  
Weather Forecasting ◽  
Weather Prediction ◽  
Urban Climate ◽  
Mitigation Strategies ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Meteorological Model ◽  
Near Surface ◽  
Urban Heat ◽  
Modelling System

Abstract. The urban heat island (UHI) effect is one prominent form of localized anthropogenic climate modification. It represents a significant urban climate problem since it occurs in that layer of the atmosphere where almost all daily human activities take place. This paper presents the development of a high-resolution modelling system that could be used for simulating the UHI effect in the context of operational weather forecasting activities. The modelling system is built around a state-of-the-art numerical weather prediction model, properly modified to allow for the better representation of the urban climate. The model performance in terms of simulating the near-surface air temperature and thermal comfort conditions over the complex urban area of Athens, Greece, is evaluated during a 1.5-month operational implementation in the summer of 2010. Results from this case study reveal an overall satisfactory performance of the modelling system. The discussion of the results highlights the important role that, given the necessary modifications, a meteorological model can play as a supporting tool for developing successful heat island mitigation strategies. This is further underlined through the operational character of the presented modelling system.

scholarly journals Development of an operational modeling system for urban heat islands: an application to Athens, Greece

2014 ◽  
Vol 14 (2) ◽  
pp. 347-358 ◽  
Author(s):  
T. M. Giannaros ◽  
D. Melas ◽  
I. A. Daglis ◽  
I. Keramitsoglou
Keyword(s):  
Weather Forecasting ◽  
Weather Prediction ◽  
Urban Climate ◽  
Model Performance ◽  
Mitigation Strategies ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Meteorological Model ◽  
Near Surface ◽  
Urban Heat

Abstract. The urban heat island (UHI) effect is one prominent form of localized anthropogenic climate modification. It represents a significant urban climate problem since it occurs in the layer of the atmosphere where almost all daily human activities take place. This paper presents the development of a high-resolution modeling system that could be used for simulating the UHI effect in the context of operational weather forecasting activities. The modeling system is built around a state-of-the-art numerical weather prediction model, properly modified to allow for the better representation of the urban climate. The model performance in terms of simulating the near-surface air temperature and thermal comfort conditions over the complex urban area of Athens, Greece, is evaluated during a 1.5-month operational implementation in the summer of 2010. Results from this case study reveal an overall satisfactory performance of the modeling system. The discussion of the results highlights the important role that, given the necessary modifications, a meteorological model can play as a supporting tool for developing successful heat island mitigation strategies. This is further underlined through the operational character of the presented modeling system.

scholarly journals Advancement in Urban Climate Modelling at Local Scale: Urban Heat Island Mitigation and Building Cooling Demand

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1313
Author(s):  
Aytaç Kubilay ◽  
Jonas Allegrini ◽  
Dominik Strebel ◽  
Yongling Zhao ◽  
Dominique Derome ◽  
...  
Keyword(s):  
Climate Model ◽  
Heat Waves ◽  
Urban Climate ◽  
Building Energy ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Meteorological Model ◽  
Heat Islands ◽  
Urban Heat ◽  
Building Cooling

As cities and their population are subjected to climate change and urban heat islands, it is paramount to have the means to understand the local urban climate and propose mitigation measures, especially at neighbourhood, local and building scales. A framework is presented, where the urban climate is studied by coupling a meteorological model to a building-resolved local urban climate model, and where an urban climate model is coupled to a building energy simulation model. The urban climate model allows for studies at local scale, combining modelling of wind and buoyancy with computational fluid dynamics, radiative exchange and heat and mass transport in porous materials including evaporative cooling at street canyon and neighbourhood scale. This coupled model takes into account the hygrothermal behaviour of porous materials and vegetation subjected to variations of wetting, sun, wind, humidity and temperature. The model is driven by climate predictions from a mesoscale meteorological model including urban parametrisation. Building energy demand, such as cooling demand during heat waves, can be evaluated. This integrated approach not only allows for the design of adapted buildings, but also urban environments that can mitigate the negative effects of future climate change and increased urban heat islands. Mitigation solutions for urban heat island effect and heat waves, including vegetation, evaporative cooling pavements and neighbourhood morphology, are assessed in terms of pedestrian comfort and building (cooling) energy consumption.

Synergistic Interactions between Urban Heat Islands and Heat Waves: The Impact in Cities Is Larger than the Sum of Its Parts

2013 ◽  
Vol 52 (9) ◽  
pp. 2051-2064 ◽  
Author(s):  
Dan Li ◽  
Elie Bou-Zeid
Keyword(s):  
Urban Heat Island ◽  
Rural Areas ◽  
Urban Areas ◽  
Heat Waves ◽  
Mitigation Strategies ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Heat Islands ◽  
Urban Heat ◽  
The Impact

AbstractCities are well known to be hotter than the rural areas that surround them; this phenomenon is called the urban heat island. Heat waves are excessively hot periods during which the air temperatures of both urban and rural areas increase significantly. However, whether urban and rural temperatures respond in the same way to heat waves remains a critical unanswered question. In this study, a combination of observational and modeling analyses indicates synergies between urban heat islands and heat waves. That is, not only do heat waves increase the ambient temperatures, but they also intensify the difference between urban and rural temperatures. As a result, the added heat stress in cities will be even higher than the sum of the background urban heat island effect and the heat wave effect. Results presented here also attribute this added impact of heat waves on urban areas to the lack of surface moisture in urban areas and the low wind speed associated with heat waves. Given that heat waves are projected to become more frequent and that urban populations are substantially increasing, these findings underline the serious heat-related health risks facing urban residents in the twenty-first century. Adaptation and mitigation strategies will require joint efforts to reinvent the city, allowing for more green spaces and lesser disruption of the natural water cycle.

scholarly journals Modelling spatiotemporal variations of the canopy layer urban heat island in Beijing at the neighbourhood scale

2021 ◽  
Vol 21 (17) ◽  
pp. 13687-13711
Author(s):  
Michael Biggart ◽  
Jenny Stocker ◽  
Ruth M. Doherty ◽  
Oliver Wild ◽  
David Carruthers ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Land Surface ◽  
Urban Climate ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Canopy Layer ◽  
Near Surface ◽  
Air Temperatures ◽  
Urban Heat ◽  
Neighbourhood Scale

Abstract. Information on the spatiotemporal characteristics of Beijing's urban–rural near-surface air temperature difference, known as the canopy layer urban heat island (UHI), is important for future urban climate management strategies. This paper investigates the variation of near-surface air temperatures within Beijing at a neighbourhood-scale resolution (∼ 100 m) during winter 2016 and summer 2017. We perform simulations using the urban climate component of the ADMS-Urban model with land surface parameters derived from both local climate zone classifications and OpenStreetMap land use information. Through sensitivity simulations, the relative impacts of surface properties and anthropogenic heat emissions on the temporal variation of Beijing's UHI are quantified. Measured UHI intensities between central Beijing (Institute of Atmospheric Physics) and a rural site (Pinggu) during the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-China) campaigns, peak during the evening at ∼ 4.5 ∘C in both seasons. In winter, the nocturnal UHI is dominated by anthropogenic heat emissions but is underestimated by the model. Higher-resolution anthropogenic heat emissions may capture the effects of local sources (e.g. residential buildings and adjacent major roads). In summer, evening UHI intensities are underestimated, especially during heatwaves. The inability to fully replicate the prolonged release of heat stored in the urban fabric may explain this. Observed negative daytime UHI intensities in summer are more successfully captured when surface moisture levels in central Beijing are increased. However, the spatial correlation between simulated air temperatures and satellite-derived land surface temperatures is stronger with a lower urban moisture scenario. This result suggests that near-surface air temperatures at the urban meteorological site are likely influenced by fine-scale green spaces that are unresolved by the available land cover data and demonstrates the expected differences between surface and air temperatures related to canopy layer advection. This study lays the foundations for future studies of heat-related health risks and UHI mitigation strategies across Beijing and other megacities.

scholarly journals Using ENVI-met simulation to analyze heat island intensity in megalopolises

Vestnik MGSU ◽  
2020 ◽  
pp. 1262-1273
Author(s):  
Le Minh Tuan ◽  
Ilkhomzhon S. Shukurov ◽  
Margarita О. Gelmanova ◽  
Mikhail Yu. Slesarev
Keyword(s):  
Air Temperature ◽  
Simulation Analysis ◽  
Urban Climate ◽  
Construction Materials ◽  
Urban Morphology ◽  
Urban Environments ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Urban Heat ◽  
Urban Microclimates

Introduction. The simulation of urban microclimates, including the urban heat island (UHI) phenomenon, has turned all the more important for urban planning. Presently, the analysis of this phenomenon is feasible thanks to high computational power of computers and links between computer modeling instruments and databases that contain information on urban environments. Advanced hardware helps to study characteristics of urban microclimates by analyzing and assessing their exposure to various climatic and anthropogenic urban factors (urban morphology, land use, construction sites, albedo, etc.) Materials and methods. ENVI-met is a software model used to simulate microclimates in urban environments. This software can optimize proportions of buildings and streets, outdoor shading, outdoor space planning, air movement, and use of construction materials in respect of thermal comfort and measures taken to mitigate consequences of urban heat islands within the framework of environmental planning of new districts. The co-authors analyze Ha Dong, a Hanoi district characterized by the high density of high-rise buildings. The co-authors consider the example of this district to study the process of detailed simulation, analysis and assessment of UHI effects. Results. ENVI-met and its simulation capacity is employed to prove that the air temperature in Wang Fu, an urban area, gradually rises from 8 am to 5 pm, when the air temperature reaches its maximal value of 32.28 °C during the period of sixteen hours. UHI intensity was maximal between midnight and 1 am on May 29, 2017, when it reached 2.41 °C. Conclusions. Cities are complex systems exposed to a wide array of interactive factors that influence the urban climate change. The value of R2 equal to 0.94 has proven the reliability of ENVI-met applied to simulate and imitate the climate of Hanoi, which is a hot and damp tropical city.

scholarly journals Modelling spatiotemporal variations of the canopy layer urban heat island in Beijing at the neighbourhood-scale

2020 ◽  
Author(s):  
Michael Biggart ◽  
Jenny Stocker ◽  
Ruth M. Doherty ◽  
Oliver Wild ◽  
David Carruthers ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Land Surface ◽  
Urban Climate ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Canopy Layer ◽  
Near Surface ◽  
Air Temperatures ◽  
Urban Heat ◽  
Neighbourhood Scale

Abstract. Information on the spatiotemporal characteristics of Beijing's urban-rural near-surface air temperature difference, known as the canopy layer urban heat island (UHI), is important for future urban climate management strategies. This paper investigates the variation of near-surface air temperatures within Beijing at a neighbourhood-scale resolution (~ 100 m) during winter 2016 and summer 2017. We perform simulations using the urban climate component of the ADMS-Urban model with land surface parameters derived from both Local Climate Zone classifications and OpenStreetMap land use information. Through sensitivity simulations, the relative impacts of surface properties and anthropogenic heat emissions on the temporal variation of Beijing's UHI are quantified. Measured UHI intensities between central Beijing (Institute of Atmospheric Physics) and a rural site (Pinggu) during the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-China) campaigns, peak during the evening at ~ 4.5 °C in both seasons. In winter, the nocturnal UHI is dominated by anthropogenic heat emissions but is underestimated by the model. Higher resolution anthropogenic heat emissions may capture the effects of local sources (e.g. residential buildings and adjacent major roads). In summer, evening UHI intensities are underestimated, especially during heatwaves. The inability to fully replicate the prolonged release of heat stored in the urban fabric may explain this. Observed negative daytime UHI intensities in summer are more successfully captured when surface moisture levels in central Beijing are increased. However, the spatial correlation between simulated air temperatures and satellite-derived land surface temperatures is stronger with a lower urban moisture scenario. This result suggests that near-surface air temperatures at the urban meteorological site are likely influenced by fine-scale green spaces that are unresolved by the available land cover data and demonstrates the expected differences between surface and air temperatures related to canopy layer advection. This study lays the foundations for future studies of heat-related health risks and UHI mitigation strategies across Beijing and other megacities.

scholarly journals Analysis of the urban heat island in representative points of the city of Bayeux / PB

2018 ◽  
Vol 7 (6) ◽  
pp. 345
Author(s):  
Amanda Mayara Paulino Da Silva
Keyword(s):  
Land Use ◽  
Urban Heat Island ◽  
Thermal Field ◽  
Urban Climate ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Thermal Discomfort ◽  
Heat Islands ◽  
Urban Heat ◽  
The City

Abstrat Urban growth has generated several socio-environmental problems and has altered the quality of life of people living in these environments. Due to the disorderly growth of cities and the various forms of urban land use and occupation, changes in the thermal field of these areas have occurred and caused the formation of urban heat islands and thermal discomfort in urban environments. Thus, the need to understand the formation of heat islands in these areas and the study of their causes and consequences grows. Given this context, the present work intends to study the urban climate of the city of Bayeux / PB, specifically the urban thermal field, and the formation of heat islands. For the accomplishment of the research, initially a bibliographical survey of the subject in question was made. Subsequently experimental points of meteorological data collection (temperature and relative air humidity) were defined in the metropolitan area of the city of João Pessoa, specifically in the municipality of Bayeux / PB. These points were defined based on the different types of land use and cover in the study area. The following experimental points were defined: a point in the center of the city of Bayeux / PB, another point on the banks of the BR230 direction Bayeux, and a reference point in a remnant of Atlantic forest. To obtain the urban heat island the reference point was used as a parameter of the climatic conditions of a natural environment. The data of temperature and relative humidity were collected through thermometers (HOBO U-10), which were placed on steel tripods (1.5 meters high) and monitored at uninterrupted intervals of 1 and 1 hour during the dry period and rainy region. The analysis of the data points to the formation of urban heat islands in the two periods evaluated in the city of Bayeux / PB, being the center of the city, the most critical area with the most intense heat islands. The vegetative cover played a predominant role in the climatic mitigation of the experimental samples as well as the presence of precipitation. The areas with impermeable soil cover presented the largest heat islands and contributed to the thermal discomfort of the study area. Keywords: Urban Climate, Thermodynamic Field, Urban Heat Island.

scholarly journals Ilhas de calor urbano em cidade do semiárido nordestino

GeoTextos ◽  
2020 ◽  
Vol 16 (2) ◽  
Author(s):  
Juliana Maria Oliveira Silva ◽  
Marcelo De Oliveira Moura ◽  
Vinicius Ferreira Luna
Keyword(s):  
Data Collection ◽  
Air Temperature ◽  
Urban Climate ◽  
Temperature Data ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Heat Islands ◽  
Intensity Category ◽  
Urban Heat ◽  
The City

<p>A pesquisa pautou-se nas concepções do Sistema Clima Urbano de Monteiro (1976) e procurou identificar e mapear as ilhas de calor urbano na cidade do Crato-CE, em dois períodos sazonais do ano. Para isso, foram selecionados 10 pontos experimentais distribuídos em bairros na zona urbana da cidade, e aferiram-se dados de temperatura do ar com termohigrômetros instalados em abrigos meteorológicos durante os meses de abril (mês chuvoso) e outubro (mês seco). A partir da coleta de dados, a categoria predominante de intensidade das Ilhas de Calor intra e interurbana para a cidade do Crato foi o de ‘Média magnitude’. O horário que ocorre a maior intensidade da ilha de calor é pela tarde, 14h, com valores superiores a 5ºC de diferença de um local para o outro. Os bairros mais densamente ocupados e com baixa cobertura vegetal apresentaram os maiores valores de temperatura, enquanto que, nos que se localizam mais próximos da encosta da chapada e com vegetação mais densa, ocorreram as temperaturas mais amenas.</p><p>Abstract</p><p>URBAN HEAT ISLANDS IN CITY OF THE NORTHEAST SEMIARID</p><p>The research was based on the conceptions of the Monteiro Urban Climate System (1976) and sought to identify and map the urban heat islands in the city of Crato/ Ce in two seasonal periods of the year. For this, 10 experimental points were selected and distributed in neighborhoods in the urban area of the city and air temperature data was measured with thermohygrometers installed in meteorological shelters during the months of April (rainy month) and October (dry month). From the data collection, the predominant intensity category of the intra and interurban Heat Islands for the city of Crato was that of ‘Medium magnitude’. The time that occurs the greatest intensity of the heat island is in the afternoon, 14h, with values above 5ºC of difference from one place to another. The most densely occupied neighborhoods and with low vegetation cover had the highest temperature values, while those located closer to the slope of the plateau and with more dense vegetation, the milder temperatures occurred.</p>

scholarly journals Urban Heat Island Mitigation Effectiveness under Extreme Heat Conditions in the Suzhou–Wuxi–Changzhou Metropolitan Area, China

2018 ◽  
Vol 57 (2) ◽  
pp. 235-253 ◽  
Author(s):  
Yan Chen ◽  
Ning Zhang
Keyword(s):  
Boundary Layer ◽  
Air Temperature ◽  
Green Roofs ◽  
Mitigation Strategies ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Near Surface ◽  
Urban Land Cover ◽  
Urban Heat ◽  
Urban Land Cover Change

AbstractCool roofs and green roofs are two important methods used to mitigate the urban heat island (UHI) effect. The Weather Research and Forecasting Model was used to investigate the UHI effect and the effectiveness of cool and green roof mitigation strategies in the Suzhou–Wuxi–Changzhou metropolitan area during an extreme heat wave episode in the summer of 2013. Both urban land-cover change and anthropogenic heat releases exacerbated high temperatures in the urban area. Notably, urban land-cover change and anthropogenic heat release were responsible for 64% and 36% of the UHI intensity, respectively. Both cool and green roofs decreased near-surface air temperatures. The most dramatic decrease in near-surface air temperature occurred in the late morning; nocturnal air temperature decreased slightly because of the decrease in urban heat storage associated with the cool roof strategy. In addition, the UHI mitigation strategies affected the entire urban boundary layer. The decrease in the potential temperature and static stability created a stable urban boundary layer in which turbulent kinetic energy (TKE) decreased simultaneously. Analysis of an urban belt near a large water body showed that the decrease in the surface skin temperature difference between land and the water body weakened the daytime lake breeze. This effect was observed in both the inflow in the boundary layer and the return flow above the boundary layer, and it decreased the heat and moisture exchange between the lake and land boundary layers.

scholarly journals The mechanisms and seasonal differences of the impact of aerosols on daytime surface urban heat island effect

2020 ◽  
Vol 20 (11) ◽  
pp. 6479-6493 ◽  
Author(s):  
Wenchao Han ◽  
Zhanqing Li ◽  
Fang Wu ◽  
Yuwei Zhang ◽  
Jianping Guo ◽  
...  
Keyword(s):  
Air Pollution ◽  
Urban Heat Island ◽  
Rural Areas ◽  
Urban Areas ◽  
Urban Climate ◽  
Dynamic Effect ◽  
Heat Island ◽  
Near Surface ◽  
Urban Heat ◽  
The Impact

Abstract. The urban heat island intensity (UHII) is the temperature difference between urban areas and their rural surroundings. It is commonly attributed to changes in the underlying surface structure caused by urbanization. Air pollution caused by aerosol particles can affect the UHII through changing (1) the surface energy balance by the aerosol radiative effect (ARE) and (2) planetary-boundary-layer (PBL) stability and airflow intensity by modifying thermodynamic structure, which is referred to as the aerosol dynamic effect (ADE). By analyzing satellite data and ground-based observations collected from 2001 to 2010 at 35 cities in China and using the WRF-Chem model, we find that the impact of aerosols on UHII differs considerably: reducing the UHII in summer but increasing the UHII in winter. This seasonal contrast is proposed to be caused by the different strengths of the ARE and ADE between summer and winter. In summer, the ARE on UHII is dominant over the ADE, cooling down surface temperature more strongly in urban areas than in rural areas because of much higher aerosol loading, and offsets the urban heating, therefore weakening UHII. In winter, however, the ADE is more dominant, because aerosols stabilize the PBL more in the polluted condition, weakening the near-surface heat transport over urban areas in both vertical and horizontal directions. This means that the heat accumulated in urban areas is dispersed less effectively, and thus the UHII is enhanced. These findings shed new light on the impact of the interaction between urbanization-induced surface changes and air pollution on urban climate.

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