The urban heat island effects can also be reduced by weather phenomona. Mar 31, 2010 the effects of vegetative cooling and the urban heat island effect research by. The uhi effect has important implications for energy consumption, air quality, and urban ecosystems. This methodology allows the uhi to be calculated on a monthly basis and downscaled to hourly for addition to weather generator data. An energy and comfort comparison between passive cooling and mitigation urban heat island techniques for residential buildings in the mediterranean region. Urban heat island in hong kong department of architecture, chinese university of hong kong page 4 of 24 period. In this study, the interactions between urban heat islands and heat waves are investigated using a combination of observational, numerical, and analytical analyses. View the article pdf and any associated supplements and figures for a period of 48 hours. The temperature difference between the city and surrounding areas is also a function of winds. Compendium of strategies describes the causes and impacts. Surface temperature has been established as a major indicator of the presence of surface urban heat island in cities and urban areas. Numerical modelling of radiative and energetic balances in the urban canopy layer s.
Although the urban heat island in hong kong has been widely investigated, there is no consensus on the most appropriate fixed point meteorological sites to be used to calculate heat island intensity. Hourly air temperature data from four weather stations one in rural site and three in urban sites for the last five year are used to study the characteristics and intensities of uhi in bangkok area. Heat waves hws are recognized as a serious threat for human health worldwide, with urban areas being more vulnerable due to the urban heat. Pdf the energetic basis of urban heat island researchgate. Synergies between urban heat island and heat waves in athens.
Measures to reduce the urban heat island effect in rosemontla petitepatrie. This paper investigates the impact of anthropogenic heat on formation of urban heat island uhi and also determines which factors can directly affect energy use in the city. This paper addresses the methodological concerns in quantifying urban heat island uhi intensity in hong kong sar, china. Measures to reduce the urban heat island effect in rosemont. Department of geography, the university of british columbia, vancouver.
Systems sustaina slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. On a hot, sunny summer day, the sun can heat dry, exposed urban surfaces, like roofs and pavement, to temperatures 50 to 90f 27 to 50c hotter than the air,5 while shaded or moist surfacesoften in more rural surroundingsremain close to air temperatures. Synergies between urban heat island and heat waves in. Introduction examining the effect of urban vegetation on the radiative budget of a city helps to guide the development of thermally comfortable urban spaces and to mitigate the uhi effect. Urban materials contribute heat to their surroundings through the way they store and release heat energy from the sun. This fact is known as the urban heat island effect.
For urban residents, the urban heat island uhi effect further exacerbates the heat stress resulting from hws. Numerical modelling of radiative and energetic balances in. Synergistic interactions between urban heat islands and heat. An urban heat island, or uhi, is a metropolitan area thats a lot warmer than the rural areas surrounding it. The highest values of the urban heat island intensity, in the region of 38 c, are often reached between about 11 oclock at night and 3 oclock in the morning figure 2. United states environmental protection agency the crosssection that is also the icon through which the uhi is represented typically possesses cliffs at the urbanrural fringe and a peak in correspondence of the most builtup core of the cities pon. White areas are around 160f 70c, while dark blue areas are near 85f 30c. The temperature difference is usually larger at night than during the day, and is most apparent when winds are weak. Compendium of strategies describes the causes and impacts of summertime urban heat islands and promotes strategies for lowering temperatures in u. A summary of urban heat island uhi characteristics epa, 20 1 u. An observational and modeling study of characteristics of.
Emphasis in this paper is upon the heat island in the urban boundary layer ubl above rooflevel the uhi ubl. Quality and sensitivity of highresolution numerical. Dec 29, 2015 these materials can increase the temperatures of an urban area in comparison to the surrounding rural land, generating an urban heat island oke, 2011. The study focuses on the characteristics of urban heat island uhi in bangkok, thailand. Interactions between urban heat islands and heat waves. The energetic basis of the urban heat island oke 1982 quarterly. Climate scientists routinely adjust down historical. Environmental protection agencys ofice of atmospheric programs. Quarterly journal of the royal meteorological society 108 455, 124, 1982. Jun 23, 2010 extreme heat events ehes are increasing in frequency in large u. Thereafter slightly greater urban cooling reduces the intensity until the early daytime rural heating virtually erases the heat island. Quantifying urban heat island intensity in hong kong sar, china. Urbanization is one of the most important humaninduced changes in land use 1, 2, and a wellknown consequence of urbanization is the urban heat island uhi, referring to the phenomenon that cities are typically warmer than the surrounding rural areas 3, 4.
Climate models consistently project that hw frequency, severity, and duration will increase markedly over this century. Heat is created by energy from all the people, cars, buses, and trains in big cities like new york, paris, and london. Zappala1,2 1osservatorio meteorologico di milanoduom, italy. Lamb, timon mcphearson, jan minx, esteban munoz, brenna walsh. A lot of the classic work done on quantifying urban heat island effects was done by oke in the 1980s, e. The energetic basis of the urban heat island symons memorial lecture, 20 may 1980. Note the warmer urban surface temperatures left side of image and cooler. Upscaling urban data science for global climate solutions volume 2 felix creutzig, steffen lohrey, xuemei bai, alexander baklanov, richard dawson, shobhakar dhakal, william f. This compendium was developed by the climate protection partnership division in the u. The urban heat island uhi is the most stud ied of the climate. The energetic basis of the urban heat island oke 1982. The two heat sources increase the temperatures of an urban area as compared to its surroundings, which is known as urban heat island intensity uhii. Heat waves hws are recognized as a serious threat for human health worldwide, with urban areas being more vulnerable due to the urban heat island uhi effect and population density.
The importance of distinguishing between different types is stressed and a simple classification scheme is forwarded. This paper presents a simulation model, which was incorporated into a geographic information system gis, in order to calculate the maximum. High temperature in the city centers than its surroundings known as the urban heat island uhi effect, which is causing discomfort to the urban dwellers in the summer time is gaining much attention around the world because the world is getting urbanized as it advances in technology. Oke and others published the energetic basis of urban heat island find, read and cite all the research you need on researchgate. Pdf the impact of urban texture in outdoor thermal comfort. Urban heat island uhi effect is a kind of heat accumulation phenomenon within urban area due to. A quantitative assessment of surface urban heat islands using. Quality and sensitivity of highresolution numerical simulation of urban heat islands view the table of contents for this issue, or go to the journal homepage for more home search collections journals about contact us my iopscience. Use the link below to share a fulltext version of this article with your friends and colleagues. Phoenix regional heat and air quality knowledge repository.
The large amount of heat generated from urban structures, as they consume and reradiate solar radiations, and from the anthropogenic heat sources are the main causes of uhi. The characteristics of urban heat island in bangkok, thailand. Urban heat islands are created in areas like these. The temperature of urban areas can be significantly higher than that of the surrounding rural areas. High temperature in the city centers than its surroundings known as the urban heat island uhi effect, which is causing discomfort to the urban dwellers in the summer time is gaining much. An analysis on the urban heat island effect using radiosonde profiles and. The energetic basis of the urban heat island symons memorial lecture, 20. The energetic basis of the urban heat island pat arnott web site. A gis extension model to calculate urban heat island intensity based on urban geometry. Urban heat island uhi is a phenomenon that occurs in cities worldwide. An urban heat island uhi is an urban area or metropolitan area that is significantly warmer than its surrounding rural areas due to human activities. Upscaling urban data science for global climate solutions. S56 seasonalvariabilityandtrendsofthemiamiurbanheat.
No, this is a separate phenomenon where cities are 68f warmer than surrounding rural areas. Surface urban heat island this image, taken from an aircraft, depicts a midday surface urban heat island in salt lake city, utah, on july, 1998. The urban canopy layer heat island international association for. The united states 1epa recognizes the importance of these small scale regions of temperature perturbation and has characterized them as listed in table 1. Heat waves hws are among the most damaging climate extremes to human society. Impact of urban heat island on regional atmospheric pollution. United states environmental protection agency the crosssection that is also the icon through which the uhi is represented typically possesses cliffs at the urbanrural fringe and a peak in correspondence of the most builtup core of the cities pon, 2007. The urban heat island effect as defined on the basis of 2m air temperature and surface temperature during a heat wave event 710 june 2008 over the baltimore area is quantified. The wellstudied use of different materials, green areas and water reduces the thermal radiation in promenades. Larger solar power plants increase local temperatures.
Trend analysis of urban heat island intensity according to. It explores literally the conceptual framework of confliction between anthropogenic heat and urban structure, which produced uhi intensity and affected energy consumption balance. Quantifying urbanrural temperature differences for. Jonathan winfrey, chris castro and zach bamman bsc 4932l. The relationship between land cover and surface temperature was analyzed for each year by producing images that provided a visual resource for analyzing the intensity and spatiality of lst change. In conclusion, the findings have indicated that on 22 june 20, surface heat island shi is critically present in the afternoon. The impact of anthropogenic heat on formation of urban heat. The energetic basis of urban heat island article pdf available in quarterly journal of the royal meteorological society 108 455. On a larger scale, the surface warming is characterized as an urban heat island uhi. After that, the findings are evaluated in terms of urban thermal comfort. An urban cool island is an urban area that is cooler than its surrounding rural areas. A gis extension model to calculate urban heat island. The urban heat island may also increase cloudiness and precipitation in the city.
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