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 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 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.

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 How the urban environment affects the microclimate and the building energy demand for the City of Rome

2019 ◽  
Vol 23 (Suppl. 4) ◽  
pp. 1035-1042 ◽  
Author(s):  
Andrea Vallati ◽  
Luca Mauri ◽  
Chiara Colucci
Keyword(s):  
Urban Heat Island ◽  
Urban Environment ◽  
Urban Area ◽  
Air Temperature ◽  
Energy Demand ◽  
The Other ◽  
Weather Data ◽  
Heat Island ◽  
Urban Heat ◽  
The City

Urban heat island has significant impacts on buildings? energy consumption. The phenomenon is associated with increased urban air temperatures compared to the air temperature of the surrounding rural or suburban areas. The ambient air temperature growth due to climate changes and the urban heat island phenomenon are dramatically increasing the cooling demand in buildings. This is worsened by irradiation conditions, construction technologies, and subjective comfort expectations. This paper examines the impact of the urban environment on the energy demand of buildings, considering the case of two districts of the city of Rome, Italy: one is representative of a central zone, the other of a rural zone. Weather data were then used to calculate the thermal demand of a typical Italian building, ideally located in the monitored areas of the city. Standalone building with modified weather file was modeled in TRNSYS. Results show that urban heat island intensity causes an increase in cooling demand up to +33% for the urban area (+20% for the rural area) compared to the demand calculated using weather data from airportual areas. On the other hand, urban heat island intensity has a positive effect on heating demand which turns out to decrease up to -32% for the urban area (-14% for the rural area).

scholarly journals Spatio-Temporal Analysis of UHI using Geo-Spatial Techniques: A case study of Ahmedabad

2014 ◽  
Vol XL-8 ◽  
pp. 997-1002 ◽  
Author(s):  
A. Vyas ◽  
B. Shastri ◽  
Y. Joshi
Keyword(s):  
Remote Sensing ◽  
Land Cover ◽  
Urban Heat Island ◽  
Urban Area ◽  
Rural Areas ◽  
Remote Sensing Data ◽  
Observation Data ◽  
Heat Island ◽  
Urban Heat ◽  
The City

As per the current estimates, nearly half of the world’s population lives in the cities, by 2030 it is calculated to increase to 70%. This calls for a need of more sustainable structure in the urban areas as to support increase in the urban population. Urban Heat Island is one such conspicuous phenomenon which has its significance at local regional and also at the global levels. It is a microscale temperature variation between urban and rural areas, in which urban area are warmer compare to surrounding rural area. The temperature difference between the urban and the rural areas are usually modest, averaging less than 1°C, but occasionally rising to several degrees when urban, topographical and meteorological conditions are favorable for the UHI to develop. It is defined as the phenomena where in the occurrence of surface and atmospheric modifications due to the urbanization causes modification in the thermal climatic conditions which results into warmer areas as compared to the surrounding non urbanized areas, particularly in night. In that case urban built forms such as buildings, roofs, pavements etc. absorb more solar heat/radiation and remain warmer throughout the day time and slowly release energy during night time. The two major causes are rapid urbanization and anthropogenic heat generated due to transport and industrial activities. Urban Heat Island is a crucial subject for global environment. Urbanization has significant effects on local weather and climate. Among these effects one of the most popular is the urban heat island, for which the temperatures of the central urban locations are several degrees higher than those of nearby rural areas of similar elevation. Satellite data provides important inputs for estimating regional surface albedo and evapo-transpiration required in the studies related to surface energy balance. <br><br> The phenomenon of UHI affects environment and population in so many ways it can also be considered as an active element that cause vulnerabilities to human health, the marginal population affected largely as the natural environment is their only home or their main shelter. Furthermore elderly people also affected in greater amount as their weakening immunes system. Major effects of UHI on environment include: a) Air Quality, b) Energy consumption and c) Human health. <br><br> To study the causes and effect of UHI of any urban area, the first step is to demarcate the spatial distribution of UHI and its intensity over different time period of the day as well as difference in the temperature of urban area with the surrounding rural areas. Secondly, study of land use land cover change in the area also helps in identifying causes of heat accumulation for particular region. After marking up of intensity, analysis of different zones for understanding the relationship between UHI and urban morphological features can be done which further became suggestive towards planning of urban center that mitigates the effect of UHI. Mainly two approaches are there to demarcate UHI study as: <br><br> &ndash; Field data collection and observations <br> &ndash; Remote sensing data analysis <br><br> For a long period of time observations from interior of the city and outwards of it can analyze by a climatic methods, by observing many days as well as many times of a day continuously to analyze the daily variation law of the heat island effects. As the city is for its developmental approaches may cover an area of hundreds of square kilometers, the ground observation data is not able to provide enough detail about the urban heat island distribution characteristics. The most precise method is the Satellite Remote Sensing method. The UHI phenomenon can be analyzed by using the thermal infrared data obtained meteorological satellite sensing. The atmospheric attenuation can be corrected for the remote sensing data by use of meteorological soundings and ground observation data. Ideally the heat island effect over a city is not same for any other city. <br><br> Satellite images from AVHRR Advanced Very High Resolution Radiometer) or ENVISAT AATSR provides thermal infrared data and comparatively easy to acquire, process and analyze. In the case of Ahmedabad city, land cover changes over the time is to be studied by classifying the image and then temperature can be derived by using a quadratic regression model from Malaret at al. (1985). Band 6 produces the images that show the relative difference emitted thermal energy that correlate in part with the effects of solar heating on surface of varying composition and orientation. The surface temperatures are suitable to detect UHI at Urban canopy level. Nichol (1996) found that surface temperatures extracted are moreover similar to the actual ambient air temperatures recorded. <br><br> The paper has narrated analylitical framework on which the research has been carried out. The result derived on Land Surface Temperature variation causing Urban Heat Island, its relationship with the land use land cover. A time series data has been used. Authors are thankful to Ms. Darshana Rawal, Ms. Pallavi Knahdewal and Mr. Hardik Panchal.

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.

Identifikasi Pertumbuhan Urban Heat Island secara Spasial-Temporal di Kota Palangka Raya Menggunakan Penginderaan Jauh dan Sistem Informasi Geografis

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Afrilyani Kontryana ◽  
Abdul Wahid Hasyim ◽  
Amin Setyo Leksono
Keyword(s):  
Surface Temperature ◽  
Urban Heat Island ◽  
Urban Area ◽  
Land Surface ◽  
Urban Areas ◽  
Landsat 8 ◽  
Heat Island ◽  
Urban Village ◽  
Urban Heat ◽  
The City

Developments in the city of Palangka Raya y giving different temperature between urban and sub-urban. Phenomenon that  cities have warmer temperatures than sub-urban and rural areas called Urban Heat Island (UHI). This study aims to find out about the development of the UHI phenomenon in the city of Palangka Raya  from 2000  to 2018 using remote sensing and geographical system. Based on the analysis of the TIR band landsat 7,  in Kota Palangka Raya since 2000 has been UHI phenomenon, where high Land Surface Temperature (LST) was found dominantly in urban areas  compared to sub-urban areas . In 2018, as Palangka Raya city  had developed, based on the result of TIR band Landsat 8, the distribution of high LST not only found in the urban area, but in the sub-urban zone, especially at  Menteng Urban Village and Panarung Urban Village. The development of UHI in Palangka Raya city over eighteen years (2000-2018) show  in the sub-urban area  experienced changes of UHIindex’s area more dynamic than the urban area. Urban development causing to conversion of  vegetated land into impervious land,  which greatly affects the energy balance. The increase in impervious areas causes more solar radiation  that reaches the surfaces of the earth   more absorbing and it is converted into sensible thermal  energy which increases the surface temperature.

scholarly journals The spatial variability of air temperature and nocturnal urban heat island intensity in the city of Brno, Czech Republic

2015 ◽  
Vol 23 (3) ◽  
pp. 8-16 ◽  
Author(s):  
Petr Dobrovolný ◽  
Lukáš Krahula
Keyword(s):  
Spatial Variability ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Temperature Measurements ◽  
City Centre ◽  
Heat Island ◽  
Entire Study ◽  
Urban Heat ◽  
Mobile Measurements ◽  
The City

AbstractThis study seeks to quantify the effects of a number of factors on the nocturnal air temperature field in a medium-sized central European city located in complex terrain. The main data sources consist of mobile air temperature measurements and a geographical database. Temperature measurements were taken along several profiles through the city centre and were made under a clear sky with no advection. Altogether nine sets of detailed measurements, in all seasons, were assembled. Altitude, quantity of vegetation, density of buildings and the structure of the transportation (road) system were considered as explanatory variables. The result is that the normalized difference vegetation index (NDVI) and the density of buildings were the most important factors, each of them explaining a substantial part (more than 50%) of overall air temperature variability. Mobile measurements with NDVI values as a covariate were used for interpolation of air temperature for the entire study area. The spatial variability of nocturnal air temperature and UHI intensity in Brno is the main output presented. Air temperatures interpolated from mobile measurements and NDVI values indicate that the mean urban heat island (UHI) intensity in the early night in summer is at its highest (approximately 5 °C) in the city centre and decreases towards the suburban areas.

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