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 Multi-model comparison of urban heat island modelling approaches

2018 ◽  
Author(s):  
Jan Karlický ◽  
Peter Huszár ◽  
Tomáš Halenka ◽  
Michal Belda ◽  
Michal Žák ◽  
...  
Keyword(s):  
Wind Speed ◽  
Urban Heat Island ◽  
Urban Environment ◽  
Model Comparison ◽  
Urban Climate ◽  
Weather Conditions ◽  
Heat Island ◽  
Significant Difference ◽  
Urban Heat ◽  
The Impact

Abstract. Cities are characterized by different physical properties of surface compared to their rural counterparts, resulting in 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 WRF and RegCM models. The specific processes occurring in the typical urban environment are described in the models by various types of urban parametrizations, greatly differing in complexity. Our results show that all models and urban parametrizations 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 parametrization 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 summer daytime, 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 Canopy Urban Heat Island and Its Association with Climate Conditions in Dubai, UAE

Climate ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 81 ◽  
Author(s):  
Afifa Mohammed ◽  
Gloria Pignatta ◽  
Evangelia Topriska ◽  
Mattheos Santamouris
Keyword(s):  
Wind Speed ◽  
Urban Heat Island ◽  
Rural Area ◽  
Air Temperature ◽  
Negative Correlation ◽  
Wind Direction ◽  
Weather Data ◽  
Heat Island ◽  
Urban Heat ◽  
The Impact

The impact that climate change and urbanization are having on the thermal-energy balance of the built environment is a major environmental concern today. Urban heat island (UHI) is another phenomenon that can raise the temperature in cities. This study aims to examine the UHI magnitude and its association with the main meteorological parameters (i.e., temperature, wind speed, and wind direction) in Dubai, United Arab Emirates. Five years of hourly weather data (2014–2018) obtained from weather stations located in an urban, suburban, and rural area, were post-processed by means of a clustering technique. Six clusters characterized by different ranges of wind directions were analyzed. The analysis reveals that UHI is affected by the synoptic weather conditions (i.e., sea breeze and hot air coming from the desert) and is larger at night. In the urban area, air temperature and night-time UHI intensity, averaged on the five year period, are 1.3 °C and 3.3 °C higher with respect to the rural area, respectively, and the UHI and air temperature are independent of each other only when the wind comes from the desert. A negative and inverse correlation was found between the UHI and wind speed for all the wind directions, except for the northern wind where no correlation was observed. In the suburban area, the UHI and both temperatures and wind speed ranged between the strong and a weak negative correlation considering all the wind directions, while a strong negative correlation was observed in the rural area. This paper concludes that UHI intensity is strongly associated with local climatic parameters and to the changes in wind direction.

scholarly journals A new method for fine-scale assessments of the average urban Heat island over large areas and the effectiveness of nature-based solutions

One Ecosystem ◽  
2018 ◽  
Vol 3 ◽  
Author(s):  
Dirk Lauwaet ◽  
Ton De Nijs ◽  
Inge Liekens ◽  
Hans Hooyberghs ◽  
Els Verachtert ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Climate Model ◽  
Climate Adaptation ◽  
Urban Climate ◽  
Horizontal Resolution ◽  
Heat Island ◽  
Adaptation Measures ◽  
Mean Wind Speed ◽  
Urban Heat ◽  
The Impact

People living in cities experience extra heat stress due to the so-called Urban Heat Island (UHI) effect. To gain an insight into the spatial variability of the UHI for the Netherlands, a detailed map (10 m horizontal resolution) has been calculated that shows the summer-averaged daily maximal UHI situation. The map is based on a relationship between the UHI, mean wind speed at 10 m height and the number of people living within a distance of 10 km, derived from simulations of over 100 European cities with the extensively validated urban climate model UrbClim. The cooling effect of green and blue infrastructure is also taken into account in the map, based on these simulation results. The presented map will help local authorities in defining target areas for climate adaptation measures and estimate the impact of nature-based solutions.

scholarly journals Review on Urban Heat Island in China: Methods, Its Impact on Buildings Energy Demand and Mitigation Strategies

2021 ◽  
Vol 13 (2) ◽  
pp. 762
Author(s):  
Liu Tian ◽  
Yongcai Li ◽  
Jun Lu ◽  
Jue Wang
Keyword(s):  
Energy Consumption ◽  
Urban Heat Island ◽  
Building Energy ◽  
Design Stage ◽  
Heat Island ◽  
Building Energy Consumption ◽  
Rapid Urbanization ◽  
Substantial Impact ◽  
Urban Heat ◽  
The Impact

High population density, dense high-rise buildings, and impervious pavements increase the vulnerability of cities, which aggravate the urban climate environment characterized by the urban heat island (UHI) effect. Cities in China provide unique information on the UHI phenomenon because they have experienced rapid urbanization and dramatic economic development, which have had a great influence on the climate in recent decades. This paper provides a review of recent research on the methods and impacts of UHI on building energy consumption, and the practical techniques that can be used to mitigate the adverse effects of UHI in China. The impact of UHI on building energy consumption depends largely on the local microclimate, the urban area features where the building is located, and the type and characteristics of the building. In the urban areas dominated by air conditioning, UHI could result in an approximately 10–16% increase in cooling energy consumption. Besides, the potential negative effects of UHI can be prevented from China in many ways, such as urban greening, cool material, water bodies, urban ventilation, etc. These strategies could have a substantial impact on the overall urban thermal environment if they can be used in the project design stage of urban planning and implemented on a large scale. Therefore, this study is useful to deepen the understanding of the physical mechanisms of UHI and provide practical approaches to fight the UHI for the urban planners, public health officials, and city decision-makers in China.

scholarly journals Characterization of the subsurface urban heat island and its sources in the Milan city area, Italy

2021 ◽  
Author(s):  
Alberto Previati ◽  
Giovanni B. Crosta
Keyword(s):  
Urban Heat Island ◽  
Urban Areas ◽  
Heat Fluxes ◽  
Shallow Aquifer ◽  
Heat Island ◽  
Groundwater Temperature ◽  
City Area ◽  
Groundwater Environment ◽  
Urban Heat ◽  
The Impact

AbstractUrban areas are major contributors to the alteration of the local atmospheric and groundwater environment. The impact of such changes on the groundwater thermal regime is documented worldwide by elevated groundwater temperature in city centers with respect to the surrounding rural areas. This study investigates the subsurface urban heat island (SUHI) in the aquifers beneath the Milan city area in northern Italy, and assesses the natural and anthropogenic controls on groundwater temperatures within the urban area by analyzing groundwater head and temperature records acquired in the 2016–2020 period. This analysis demonstrates the occurrence of a SUHI with up to 3 °C intensity and reveals a correlation between the density of building/subsurface infrastructures and the mean annual groundwater temperature. Vertical heat fluxes to the aquifer are strongly related to the depth of the groundwater and the density of surface structures and infrastructures. The heat accumulation in the subsurface is reflected by a constant groundwater warming trend between +0.1 and + 0.4 °C/year that leads to a gain of 25 MJ/m2 of thermal energy per year in the shallow aquifer inside the SUHI area. Future monitoring of groundwater temperatures, combined with numerical modeling of coupled groundwater flow and heat transport, will be essential to reveal what this trend is controlled by and to make predictions on the lateral and vertical extent of the groundwater SUHI in the study area.

The impact of COVID-19 lockdowns on surface urban heat island changes and air-quality improvements across 21 major cities in the Middle East

2021 ◽  
pp. 117802
Author(s):  
Ahmed M. El Kenawy ◽  
Juan I. Lopez-Moreno ◽  
Matthew F. McCabe ◽  
Fernando Domínguez-Castro ◽  
Dhais Peña-Angulo ◽  
...  
Keyword(s):  
Air Quality ◽  
Middle East ◽  
Urban Heat Island ◽  
Heat Island ◽  
Quality Improvements ◽  
Urban Heat ◽  
Surface Urban Heat Island ◽  
The Impact

scholarly journals The Impact of the Urban Heat Island during an Intense Heat Wave in Oklahoma City

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Jeffrey B. Basara ◽  
Heather G. Basara ◽  
Bradley G. Illston ◽  
Kenneth C. Crawford
Keyword(s):  
Urban Heat Island ◽  
Heat Wave ◽  
Rural Areas ◽  
Oklahoma City ◽  
Apparent Temperature ◽  
Heat Island ◽  
Atmospheric Conditions ◽  
Urban Heat ◽  
The Impact ◽  
Intense Heat

During late July and early August 2008, an intense heat wave occurred in Oklahoma City. To quantify the impact of the urban heat island (UHI) in Oklahoma City on observed and apparent temperature conditions during the heat wave event, this study used observations from 46 locations in and around Oklahoma City. The methodology utilized composite values of atmospheric conditions for three primary categories defined by population and general land use: rural, suburban, and urban. The results of the analyses demonstrated that a consistent UHI existed during the study period whereby the composite temperature values within the urban core were approximately C warmer during the day than the rural areas and over C warmer at night. Further, when the warmer temperatures were combined with ambient humidity conditions, the composite values consistently revealed even warmer heat-related variables within the urban environment as compared with the rural zone.

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