scholarly journals Lisbon Urban Heat Island Updated: New Highlights about the Relationships between Thermal Patterns and Wind Regimes

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
António Lopes ◽  
Elis Alves ◽  
Maria João Alcoforado ◽  
Raquel Machete
Keyword(s):  
Urban Heat Island ◽  
Urban Climate ◽  
City Centre ◽  
Heat Island ◽  
Local Wind ◽  
Urban Heat ◽  
Thermal Patterns ◽  
Wind Regimes ◽  
The Relationship ◽  
The City

Urban growth implies significant modifications in the urban climate. To understand the influence of the city of Lisbon on the urban boundary layer, a mesoscale meteorological network was installed in 2004. The main goals of the present study are to update the results of the research published in 2007 and to bring more precise information about the relationship between the Urban Heat Island (UHI) and the regional and local wind systems. The highest frequencies of the UHI were found in the city centre (Restauradores). In the green park of Monsanto, the highest frequency occurred between −2 and 0°C. During the summer, the effect of the breezes was observed in Belém, lowering the temperature. The “strong” UHI (intensity >4°C) occurred more often during the summer, with median values of 2°C by night and 1.8°C by day. The highest frequencies of UHI occurred for winds between 2 and 6 m/s and were not associated with atmospheric calm, as pointed out in the literature. Winds above 8 m/s inhibit the occurrence of strong UHI in Lisbon. Summer nighttime strong UHI should be further investigated, due to the heat stress consequences on the population and probable increase of energy consumption.

Climate Bubbles: Games to Monitor Urban Climate

Leonardo ◽  
2011 ◽  
Vol 44 (1) ◽  
pp. 64-65
Author(s):  
Drew Hemment ◽  
Carlo Buontempo ◽  
Alfie Dennen
Keyword(s):  
Urban Heat Island ◽  
Air Flow ◽  
Urban Climate ◽  
Heat Island ◽  
Local Climate ◽  
Flow Circulation ◽  
Urban Heat ◽  
The City

Climate Bubbles was a playful, participatory mass observation project on local climate. Bubble blowing games were devised to enable people across the city of Manchester to test air flow circulation and, by sharing the results online, enabled the Met Office to create a snapshot of the effect the Urban Heat Island has on wind.

scholarly journals Large seasonal and diurnal anthropogenic heat flux across four Australian cities

2016 ◽  
Vol 66 (3) ◽  
pp. 342
Author(s):  
S. Chapman ◽  
J.E.M. Watson ◽  
C.A. McAlpine
Keyword(s):  
Heat Release ◽  
Urban Heat Island ◽  
Anthropogenic Heat ◽  
City Centre ◽  
Heat Island ◽  
Capital Cities ◽  
Australian Capital ◽  
Daily Average ◽  
Urban Heat ◽  
The City

Anthropogenic heat release is a key component of the urban heat island. However, it is often excluded from studies of the urban heat island because reliable estimates are not available. This omission is important because anthropogenic heat can contribute up to 4ºC to the urban heat island, and increases heat stress to urban residents. The exclusion of anthropogenic heat means the urban heat island effect on temperatures may be under-estimated. Here we estimate anthropogenic heat for four Australian capital cities (Brisbane, Sydney, Melbourne and Adelaide) to inform the management of the urban heat island in a changing climate. Anthropogenic heat release was calculated using 2011 population census data and an inventory of hourly traffic volume, building electricity and gas use. Melbourne had the highest annual daily average anthropogenic heat emissions, which reached 376 W/m2in the city centre during the daytime, while Brisbane’s emissions were 261 W/m2 and Sydney’s were 256W/m2. Adelaide had the lowest emissions, with a daily average of 39 W/m2 in the city centre. Emissions varied within and among the four cities and decreased rapidly with distance from the city centre, to 2 at 20 km from the city in Brisbane, and 15 km in Adelaide. The highest emissions were found in the city centres during working hours. The peak emissions reached in the centre of Melbourne are similar to the peak emissions in London and Tokyo, where anthropogenic heat is a large component of the urban heat island. This indicates that anthropogenic heat could be an important contributor to the urban heat island in Australian capital cities, and needs to be considered in climate adaptation studies. This is an important problem because climate change, combined with an ageing population and urban growth, could double the deaths from heatwaves in Australian cities over the next 40 years.

Analysis of temperature trends and urban heat island in Madrid

2020 ◽  
Author(s):  
Gregorio Maqueda ◽  
Carlos Yagüe ◽  
Carlos Román-Cascón ◽  
Encarna Serrano ◽  
Jon Ander Arrillaga
Keyword(s):  
Urban Heat Island ◽  
Urban Areas ◽  
Surface Energy Budget ◽  
City Centre ◽  
Synoptic Situation ◽  
Heat Island ◽  
Temperature Trends ◽  
Measuring Period ◽  
Urban Heat ◽  
The City

<p>The temperature in the cities is affected by both global climate change and local changes due to human activities and the different land use compared to rural surroundings. These local changes, which modify the surface energy budget in urban areas, include the replacement of the natural surfaces by buildings and pavements and the heat of anthropogenic origin (heating, air conditioning, traffic). Madrid city (Spain) has a current population of near 3.3 million people and a larger metropolitan area reaching around 6.5 million people. Hence, it is affected by the phenomenon called urban heat island (UHI), which indicates that a higher temperature is found in the city compared with the surrounding rural areas. UHI is defined as the temperature difference between the urban observatory and the rural one and especially affects the minimum temperatures since urban areas cool down to a lesser extent than the neighbouring rural sites. Moreover, the intensity of the UHI is modulated by the meteorological conditions (wind, cloudiness, surface pressure, precipitation), highly associated with different synoptic situations. In this work, we use the Madrid-Retiro meteorological station as the urban one, which has regular and homogeneous data from the beginning of XX century; and the station at Barajas airport (12 km from the city centre) as well as other stations out of Madrid city (but within a range of 20 km from the city centre) as the rural stations. They all have a common measuring period from 1961 until present. The main objectives of the work are: 1) to identify temperature trends in the meteorological stations (both urban and rural); 2) to evaluate the intensity of the UHI for the different rural stations; 3) to apply a systematic and objective algorithm to classify each day in different categories (related to synoptic situation) that produce a different degree of UHI intensity; and, 4) to evaluate possible trends in the UHI intensity.</p>

scholarly journals The diurnal evolution of the urban heat island of Paris: a model-based case study during Summer 2006

2013 ◽  
Vol 13 (17) ◽  
pp. 8525-8541 ◽  
Author(s):  
H. Wouters ◽  
K. De Ridder ◽  
M. Demuzere ◽  
D. Lauwaet ◽  
N. P. M. van Lipzig
Keyword(s):  
Boundary Layer ◽  
Urban Heat Island ◽  
Sensible Heat Flux ◽  
City Centre ◽  
Heat Island ◽  
Regional Prediction ◽  
Prevailing Wind Direction ◽  
Adiabatic Cooling ◽  
Urban Heat ◽  
The City

Abstract. The urban heat island (UHI) over Paris during summer 2006 was simulated using the Advanced Regional Prediction System (ARPS) updated with a simple urban parametrization at a horizontal resolution of 1 km. Two integrations were performed, one with the urban land cover of Paris and another in which Paris was replaced by cropland. The focus is on a five-day clear-sky period, for which the UHI intensity reaches its maximum. The diurnal evolution of the UHI intensity was found to be adequately simulated for this five day period. The maximum difference at night in 2 m temperature between urban and rural areas stemming from the urban heating is reproduced with a relative error of less than 10%. The UHI has an ellipsoidal shape and stretches along the prevailing wind direction. The maximum UHI intensity of 6.1 K occurs at 23:00 UTC located 6 km downstream of the city centre and this largely remains during the whole night. An idealized one-column model study demonstrates that the nocturnal differential sensible heat flux, even though much smaller than its daytime value, is mainly responsible for the maximum UHI intensity. The reason for this nighttime maximum is that additional heat is only affecting a shallow layer of 150 m. An air uplift is explained by the synoptic east wind and a ramp upwind of the city centre, which leads to a considerable nocturnal adiabatic cooling over cropland. The idealized study demonstrates that the reduced vertical adiabatic cooling over the city compared to cropland induces an additional UHI build-up of 25%. The UHI and its vertical extent is affected by the boundary-layer stability, nocturnal low-level jet as well as radiative cooling. Therefore, improvements of representing these boundary-layer features in atmospheric models are important for UHI studies.

scholarly journals Anthropogenic and natural drivers of a strong winter urban heat island in a typical Arctic city

2018 ◽  
Author(s):  
Mikhail Varentsov ◽  
Pavel Konstantinov ◽  
Alexander Baklanov ◽  
Igor Esau ◽  
Victoria Miles ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Temperature Anomaly ◽  
Urban Climate ◽  
Thermal Conditions ◽  
Cold Climate ◽  
The Arctic ◽  
City Centre ◽  
Heat Island ◽  
Strong Argument ◽  
Urban Heat

Abstract. The Arctic has rapidly urbanized in recent decades with two million people currently living in more than a hundred cities north of 65° N. These cities have a harsh but sensitive climate and warming here is the principle driver of destructive thawing, water leakages, air pollution, and other detrimental environmental impacts. This study reports on the urban temperature anomaly in a typical Arctic city. This persistent warm anomaly reaches up to 11  K in winter with the wintertime mean urban temperature being on average 1.9 K higher in the city centre than in the surrounding natural landscape. An urban temperature anomaly, also known as an urban heat island (UHI), was found in remote sensing and in situ temperature data. High-resolution (1 km) model experiments run with and without an urban surface parametrization helped to identify the leading physical and geographical factors supporting a strong temperature anomaly in a cold climate. The statistical analysis and modelling suggest that direct anthropogenic heating contributes at least 50 % to the observed UHI intensity, and the rest is created by natural microclimatic variability over the undulating relief of the area. The current UHI effect can be as large as the projected, and already amplified, warming for the region in the 21st century. In contrast to earlier reports, this study found that the wintertime UHI in the Arctic should be largely attributed to direct anthropogenic heating. This is a strong argument in support of energy efficiency measures, urban climate change mitigation policy, and against high-density urban development in polar settlements. The complex pattern of thermal conditions, as revealed in this study, challenges urban planners to account for the observed micro-climatic diversity in perspective sustainable development solutions.

scholarly journals The diurnal evolution of the urban heat island of Paris: a model-based case study during Summer 2006

2012 ◽  
Vol 12 (10) ◽  
pp. 25941-25981
Author(s):  
H. Wouters ◽  
K. De Ridder ◽  
N. P. M. van Lipzig ◽  
M. Demuzere ◽  
D. Lauwaet
Keyword(s):  
Urban Heat Island ◽  
Rural Areas ◽  
Sensible Heat Flux ◽  
Horizontal Resolution ◽  
City Centre ◽  
Heat Island ◽  
Regional Prediction ◽  
Prevailing Wind Direction ◽  
Urban Heat ◽  
The City

Abstract. The urban heat island (UHI) over Paris during summer 2006 was simulated using the Advanced Regional Prediction System (ARPS) updated with a simple urban parametrization at a horizontal resolution of 1 km. Two integrations were performed, one with the urban land cover of Paris and another in which Paris was replaced by cropland. The focus is on a five-day clear-sky period, for which the UHI intensity reaches its maximum. The diurnal evolution of the UHI intensity was found to be adequately simulated for this five day period. The maximum difference at night in 2-m temperature between urban and rural areas stemming from the urban heating is reproduced with a relative error of less than 10%. The UHI has an ellipsoidal shape and stretches along the prevailing wind direction. The maximum UHI intensity of 6.1 K occurs at 23:00 UTC located 6 km downstream of the city centre and this largely remains during the whole night. An idealized one-column model study demonstrates that the nocturnal differential sensible heat flux, even though much smaller than its daytime value, is mainly responsible for the maximum UHI intensity. The reason for this nighttime maximum is that additional heat is only affecting a shallow layer of 150 m. At the same time, an idealized study shows that the orography around the city of Paris induces an uplift. This leads to a considerable nocturnal adiabatic cooling over cropland. In contrast, this uplift has little effect on the mixed-layer temperature over the city. About twenty percent of the total maximum UHI intensity is estimated to be caused by this uplift.

scholarly journals Variabilidad temporal de la isla de calor urbana de la ciudad de Zaragoza (España)

2021 ◽  
Author(s):  
José M. Cuadrat ◽  
Roberto Serrano-Notivoli ◽  
Samuel Barrao ◽  
Miguel Ángel Saz ◽  
Ernesto Tejedor
Keyword(s):  
Urban Heat Island ◽  
Urban Area ◽  
City Centre ◽  
Heat Island ◽  
Time Data ◽  
Wind Speeds ◽  
Urban Heat ◽  
The City ◽  
Temporal Intensity

We analyse the temporal intensity and variability of the urban heat island (UHI) in the city of Zaragoza (Spain), and assess the role of wind as an important atmospheric conditioning factor. Based on the time data provided by the city’s urban mesoscale meteorological network, the temperature difference between two observatories, one urban (Plaza Santa Marta) and one located on the outskirts of the urban area (Ciudad Deportiva), was calculated for the 2015-2020 period. The results indicate that the temperature in the city centre is very frequently 1º or 2ºC higher than in the surroundings, sometimes even more than 8ºC higher. The UHI is more intense in summer (an average of 2.5ºC per hour) than in winter (an average of 2.2ºC per hour) and more intense during the night than during the day. The maximum UHI value is reached in calm atmospheric situations; however, this value is very limited with winds over 10 km/h and it practically disappears with wind speeds over 50 km/h.

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 Does historic construction suffer or benefit from the urban heat island effect in Ghent and global warming across Europe?

2019 ◽  
Vol 46 (11) ◽  
pp. 1032-1042 ◽  
Author(s):  
Isabeau Vandemeulebroucke ◽  
Klaas Calle ◽  
Steven Caluwaerts ◽  
Tim De Kock ◽  
Nathan Van Den Bossche
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Urban Heat Island Effect ◽  
City Centre ◽  
Heat Island ◽  
Freeze Thaw ◽  
Island Effect ◽  
Northern Latitudes ◽  
Urban Heat ◽  
The City

Renovating historical buildings with valuable facades often includes interior retrofitting, perhaps entailing an increased durability risk. However, the urban heat island effect and the ongoing climate change might mitigate the severity of frost action and mould growth. By means of heat air moisture (HAM) simulations in Delphin, this study evaluates interior retrofitting of solid masonry on three scales. First, the sensitivity to the intra-urban climatic differences of the freeze–thaw cycles in Ghent is analysed. Secondly, the spatial pattern of freeze–thaw behaviour across Europe is assessed. Finally, the influence of observed climate change on the European freeze–thaw pattern is investigated. A decreasing number of critical freeze–thaw cycles is found when comparing the rural area with the city centre of Ghent. Furthermore, due to climate change, the number of freeze–thaw cycles across Europe generally decreases as well, except at northern latitudes exposed to increased wind-driven rain loads.

scholarly journals Multi-annual variability of summertime atmospheric and surface urban heat island in Kraków, Poland

2021 ◽  
Author(s):  
Monika J. Hajto ◽  
Anita Bokwa
Keyword(s):  
Spatial Distribution ◽  
Urban Heat Island ◽  
Spatial Resolution ◽  
Heat Load ◽  
Detailed Knowledge ◽  
Heat Island ◽  
Diurnal Variability ◽  
Urban Heat ◽  
The Relationship ◽  
The City

<p>The urban heat island (UHI) effect is primarily related to the atmosphere, but may also refer to the surfaces. The atmospheric UHI (AUHI), determined using air temperature (Tair), and the surface UHI (SUHI), assessed using land surface temperature (LST), are distinguished. There is undoubtedly a relationship between SUHI and AUHI due to the modulation of Tair by LST. On hot days in the summer months, the SUHI/AUHI effect may increase the heat load, which is dangerous to the health and comfort of people staying in the city. Detailed characteristics of the spatial distribution of Tair and LST in urban areas are required to identify the parts of the city with the highest heat load. Spatially continuous Tair data, enabling better characterizing AUHI, can be obtained by modelling. Satellite thermal data (LST) can be used as input to the Tair spatial distribution model. Satellite data with 1 km spatial resolution, due to availability several times a day, are most useful in characterizing SUHI diurnal variability and the relationship of LST with Tair. The detailed knowledge of LST and Tair correlation should be helpful in the development of the Tair estimation algorithm based on the LST values. Better recognition of the relationship between LST and Tair, and thus improving the quality of modelling the spatial distribution of Tair in urban area, can possibly be achieved through downscaling of LST data to higher spatial resolution. In the study the method of LST downscaling from 1 km to 100 m was developed, using LST derived from AVHRR, Landsat, ASTER and ECOSTRESS data. The LST-Tair correlation in the diurnal course was examined and the influence of LST downscaling on the correlation was assessed. A Tair regression model was developed based on LST, depending on local climate zone (LCZ). LST and Tair maps for Kraków and its vicinities were prepared, and on the basis of them the intensities of AUHI and SUHI in the multi-year period (2010-2019) in the summer months (June, July, August) were determined, separately for day and night.</p>

Sign in / Sign up

Export Citation Format

Share Document