Measurement and Statistical Modeling of the Urban Heat Island of the City of Utrecht (the Netherlands)

2012 ◽  
Vol 51 (6) ◽  
pp. 1046-1060 ◽  
Author(s):  
Theo Brandsma ◽  
Dirk Wolters
Keyword(s):  
Land Use ◽  
Wind Speed ◽  
The Netherlands ◽  
Urban Heat Island ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Urban Heat ◽  
The Mean ◽  
View Factors ◽  
The City

AbstractMobile temperature and humidity measurements have been performed along a 14-km transect through the city of Utrecht, in the Netherlands (311 000 inhabitants), during the period March 2006–January 2009. The measurements took place on a bicycle during commuter traffic and resulted in 106 nighttime profiles (before sunrise) and 77 daytime (afternoon) profiles. It is shown how the intensity of the urban heat island depends on wind direction, cloudiness, and wind speed. Statistical models are constructed that relate the mean and maximum nighttime urban heat island intensity profiles to area-averaged sky-view factors and land use combined at both the micro- and local scales. Sky-view factors are estimated from a 0.5 m × 0.5 m surface elevation database, and land use is obtained from a 25 m × 25 m land-use database. The models are calibrated using the mobile measurements and provide estimates of the spatial distribution of the mean and maximum nighttime urban heat island intensity in Utrecht. Both models explain more than 75% of the variance. A separate nonlinear model is introduced that relates the temperature differences between the warmest part and coolest part of the transects to wind speed and cloudiness.

scholarly journals Radon-based technique for the analysis of atmospheric stability – a case study from Central Poland

Nukleonika ◽  
2018 ◽  
Vol 63 (2) ◽  
pp. 47-54 ◽  
Author(s):  
Agnieszka Podstawczyńska ◽  
Scott D. Chambers
Keyword(s):  
Wind Speed ◽  
Temperature Gradient ◽  
Urban Heat Island ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Vertical Temperature Gradient ◽  
Mixing State ◽  
Vertical Temperature ◽  
Near Surface ◽  
Urban Heat

Abstract An economical and easy-to-implement technique is outlined by which the mean nocturnal atmospheric mixing state (“stability”) can be assessed over a broad (city-scale) heterogeneous region solely based on near-surface (2 m above ground level [a.g.l.]) observations of the passive tracer radon-222. The results presented here are mainly based on summer data of hourly meteorological and radon observations near Łodź, Central Poland, from 4 years (2008–2011). Behaviour of the near-surface wind speed and vertical temperature gradient (the primary controls of the nocturnal atmospheric mixing state), as well as the urban heat island intensity, are investigated within each of the four radon-based nocturnal stability categories derived for this study (least stable, weakly stable, moderately stable, and stable). On average, the most (least) stable nights were characterized by vertical temperature gradient of 1.1 (0.5)°C·m−1, wind speed of ~0.4 (~1.0) m·s−1, and urban heat island intensity of 4.5 (0.5)°C. For sites more than 20 km inland from the coast, where soils are not completely saturated or frozen, radon-based nocturnal stability classification can significantly enhance and simplify a range of environmental research applications (e.g. urban climate studies, urban pollution studies, regulatory dispersion modelling, and evaluating the performance of regional climate and pollution models).

scholarly journals Spatial Variation of Land Use/Cover Composition and Impact on Surface Urban Heat Island in a Tropical Sub-Saharan City of Accra, Ghana

2020 ◽  
Vol 12 (19) ◽  
pp. 7953
Author(s):  
Darshana Athukorala ◽  
Yuji Murayama
Keyword(s):  
Land Use ◽  
Urban Heat Island ◽  
Heat Island ◽  
Human Beings ◽  
Rapid Urbanization ◽  
Bare Land ◽  
Urban Rural ◽  
Urban Heat ◽  
The Mean ◽  
Sub Saharan

Rapid urbanization is one of the most crucial issues in the world of the 21st century. Notably, the urban heat island phenomenon is becoming more prominent in megacities and their hinterlands in temperate and subtropical climatic regions. In the daytime in summer, there exists a high possibility of accelerating the land surface temperature (LST) in desert cities, due to the alterations made by human beings in the natural environment. In this study, we investigate the spatial formation of LST in a tropical sub-Saharan city of Accra, a gateway to West Africa, using Landsat data in 2003 and 2017. Machine learning techniques and the different spatial and statistical methods such as tasseled cap transformation (TCT), urban-rural gradient, and multiresolution grid-based and landscape metrics were employed to examine procured land use/cover (LUC) and LST maps. LUC was classified into five categories: Built up, Green 1, Green 2, Bare land, and Water. The results of the analysis indicate that Built up, Green 2, and Bare land had caused the highest heating effect while Green 1 and Water had caused the considerable cooling effect during the daytime in Accra. The urban-rural difference in LST recorded 1.4 °C in 2003 and 0.28 °C in 2017. The mean size, mean shape, largest patch, and aggregation of Built up, Green 1, and Green 2 had a strong relationship with the mean LST. It is essential for urban planners to carefully examine the formation and effect of the urban heat island (UHI) for sustainable urban development and landscape policy toward mitigation and adaptation planning in Accra.

Modelling Inter-pixel Spatial Variation of Surface Urban Heat Island Intensity

2021 ◽  
Author(s):  
Yanhua Chen ◽  
Wendy Y. Chen ◽  
Raffaele Lafortezza
Keyword(s):  
Land Use ◽  
Spatial Variation ◽  
Urban Heat Island ◽  
Heat Load ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Density Curve ◽  
Gaussian Density ◽  
Urban Heat ◽  
Surface Urban Heat Island

Abstract Context Surface urban heat island intensity (SUHII) is a classical measure, which is sensitive to the selection of pixels/measurements representative of urban and rural areas, and overlooks pixel-level SUHII variation and thermodynamics of heterogeneous urban landscape. Accounting inter-pixel landscape heterogeneity in SUHII would capture inter-pixel thermodynamics and reveal complicated micro-thermal situations, contribute to assessment of potential heat risks at micro-pixel scale. Objectives This study develops [[EQUATION]] using pixel-based sharpening enhancement method. It integrates a pixel’s LST magnitude that reflects a city’s thermal context with local SUHII considering landscape variations and cognate thermal interactions of neighboring pixels. Methods [[EQUATION]] is constructed using MODIS LST product for Guangzhou (south China) in the summer season of 2015 through cloud-based GEE platform. Its effectiveness is tested using a bivariate choropleth map and Gaussian density curve with stepwise increments of the thermal influence from neighboring pixels. Results We found that (1) local SUHII variations are sensitive to the spatial configuration of a center pixel’s land use and that of its neighbors; (2) [[EQUATION]] makes more pronounced those spots that are heat per se (with higher original LST), but also receive additional heat load from adjacent pixels due to land-use homogeneity; (3) the effectiveness of [[EQUATION]] could be demonstrated by Gaussian density curve. Conclusions This paper proposed a new SHUII indicator, [[EQUATION]] , which models inter-pixel spatial variation of SHUI and highlights how neighboring pixels’ homogenous/heterogeneous land-use and associated thermal properties could affect center pixels’ thermal characteristics via either reinforcement or mitigation of heat load.

scholarly journals MONITORING SPATIOTEMPORAL CHANGES OF HEAT ISLAND IN BABOL CITY DUE TO LAND USE CHANGES

2017 ◽  
Vol XLII-4/W4 ◽  
pp. 17-22 ◽  
Author(s):  
S. K. Alavi Panah ◽  
M. Kiavarz Mogaddam ◽  
M. Karimi Firozjaei
Keyword(s):  
Land Use ◽  
Surface Temperature ◽  
Urban Heat Island ◽  
Land Surface ◽  
Land Use Changes ◽  
Heat Island ◽  
Time Period ◽  
Urban Heat ◽  
The City ◽  
Very High

Urban heat island is one of the most vital environmental risks in urban areas. The advent of remote sensing technology provides better visibility due to the integrated view, low-cost, fast and effective way to study and monitor environmental and humanistic changes. The aim of this study is a spatiotemporal evaluation of land use changes and the heat island in the time period of 1985-2015 for the studied area in the city of Babol. For this purpose, multi-temporal Landsat images were used in this study. For calculating the land surface temperature (LST), single-channel and maximum likelihood algorithms were used, to classify Images. Therefore, land use changes and LST were examined, and thereby the relationship between land-use changes was analyzed with the normalized LST. By using the average and standard deviation of normalized thermal images, the area was divided into five temperature categories, inter alia, very low, low, medium, high and very high and then, the heat island changes in the studied time period were investigated. The results indicate that land use changes for built-up lands increased by 92%, and a noticeable decrease was observed for agricultural lands. The Built-up land changes trend has direct relation with the trend of normalized surface temperature changes. Low and very low-temperature categories which follow a decreasing trend, are related to lands far away from the city. Also, high and very high-temperature categories whose areas increase annually, are adjacent to the city center and exit ways of the town. The results emphasize on the importance of attention of urban planners and managers to the urban heat island as an environmental risk.

scholarly journals Synergies between urban heat island and heat waves in Seoul: The role of wind speed and land use characteristics

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243571
Author(s):  
Jack Ngarambe ◽  
Jacques Nganyiyimana ◽  
Inhan Kim ◽  
Mat Santamouris ◽  
Geun Young Yun
Keyword(s):  
Land Use ◽  
Wind Speed ◽  
Urban Heat Island ◽  
Rural Areas ◽  
Urban Areas ◽  
Heat Waves ◽  
Weather Conditions ◽  
Heat Island ◽  
Emergency Relief ◽  
Urban Heat

The effects of heat waves (HW) are more pronounced in urban areas than in rural areas due to the additive effect of the urban heat island (UHI) phenomenon. However, the synergies between UHI and HW are still an open scientific question and have only been quantified for a few metropolitan cities. In the current study, we explore the synergies between UHI and HW in Seoul city. We consider summertime data from two non-consecutive years (i.e., 2012 and 2016) and ten automatic weather stations. Our results show that UHI is more intense during HW periods than non-heat wave (NHW) periods (i.e., normal summer background conditions), with a maximum UHI difference of 3.30°C and 4.50°C, between HW and NHW periods, in 2012 and 2016 respectively. Our results also show substantial variations in the synergies between UHI and HW due to land use characteristics and synoptic weather conditions; the synergies were relatively more intense in densely built areas and under low wind speed conditions. Our results contribute to our understanding of thermal risks posed by HW in urban areas and, subsequently, the health risks on urban populations. Moreover, they are of significant importance to emergency relief providers as a resource allocation guideline, for instance, regarding which areas and time of the day to prioritize during HW periods in Seoul.

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 Variação Microclimática de Sítios Urbanos com Diferentes Níveis de Cobertura Vegetal Como Subsídio à Formação de Ilha de Calor

2020 ◽  
Vol 13 (07) ◽  
pp. 3254
Author(s):  
Pedro Hugo Oliveira Moreira ◽  
Alan Cavalcanti da Cunha ◽  
João De Athaydes Silva Júnior ◽  
Antonio Carlos Lola da Costa
Keyword(s):  
Land Use ◽  
Relative Humidity ◽  
Urban Heat Island ◽  
Urban Space ◽  
Vegetation Index ◽  
Data Series ◽  
Heat Island ◽  
Urban Heat ◽  
Meteorological Elements ◽  
The City

O objetivo da investigação é analisar variações espaciais e sazonais de elementos meteorológicos que evidenciam a formação e ocorrência do fenômeno da Ilha de Calor Urbana (ICU) na cidade de Macapá. A metodologia de estudo avaliou a evolução histórica da cobertura de vegetação e da malha urbana utilizando-se técnicas de geoprocessamento e de classificação supervisionada de Máxima Verossimilhança (MAXVER). Com este objetivo foram analisadas séries de dados contínuos coletados durante dez dias consecutivos nos períodos chuvoso (Abril/2018), Seco (Novembro/2018) e Transição (Junho/2019). Os elementos meteorológicos quantificados foram a umidade relativa do ar (UR) e a temperatura média do ar (T). Cinco estações semi-automáticas foram estrategicamente distribuídas ao longo de dois eixos de máximo prolongamento da zona urbana de Macapá, nos sentidos Nordeste-Sudoeste e Oeste-Leste. Os resultados indicaram significativa variação sazonal da Temperatura e da Umidade Relativa (p<0,05). Espacialmente, os resultados também foram significativos (p<0,05), sugerindo influência espaço-sazonal dos padrões de variabilidade de T e UR sobre ICU correlacionados com as taxas de uso e ocupação do solo. Assim, ICU mostrou-se significativamente dependente tanto do índice de vegetação (R2=0,47, p<0,05) quanto do índice de urbanização (R2=0,62, p<0,05). Conclui-se que a sazonalidade diária observada sugere existência do fenômeno da ilha de calor urbana, especialmente nas zonas central e sul da cidade, cujos índices inclusive têm sido confirmados por estudos similares. Os dados de sazonalidade dos elementos meteorológicos analisados, sua relação com o uso do solo, podem trazer elementos importantes para o debate sobre a formação da ICU nas cidades amazônicas. Microclimatic Variation in Urban Sites with Different Levels of Vegetable Cover as a Subsidy to the Formation of Heat Island A B S T R A C TThe objective of the investigation is to analyze spatial and seasonal variations of meteorological elements that evidence the formation and occurrence of the phenomenon of the Urban Heat Island (UHI) in the city of Macapá. The study methodology comprised the historical evolution of vegetation cover and urban space using geoprocessing techniques and supervised classification of Maximum Likelihood (MAXVER). With this objective, continuous data series collected during ten consecutive days in the rainy (April/2018), Dry (November/2018) and Intermediate (June/2019) periods were analyzed. The meteorological elements quantified were relative humidity (RH) and average air temperature (T). Five semi-automatic gauges were strategically distributed along two axes of maximum extension of the urban area of Macapá, in the Northeast-Southwest and West-East directions. The results indicated significant seasonal variation of Temperature and Relative Humidity (p<0.05). Spatially, the results were also significant (p<0.05), suggesting influence of T and RH variability patterns on UHI correlated with land use and occupation rates on. Thus, ICU was significantly dependent on both the vegetation index (R2=0.47, p<0.05) and the urbanization index (R2=0.62, p<0.05). We concluded that the daily seasonality observed suggests the existence of the phenomenon of the urban heat island, especially in the central and southern zones of the city, whose indices have even been confirmed by similar studies. The seasonality data of the meteorological elements analyzed, their relationship with land use, can bring important elements to the debate on the formation of ICU in Amazonian cities.Keywords: Meteorological element, vegetation, urbanization, urban heat island, Macapá.

scholarly journals Spatial and Temporal Characteristics of Beijing Urban Heat Island Intensity

2013 ◽  
Vol 52 (8) ◽  
pp. 1803-1816 ◽  
Author(s):  
Ping Yang ◽  
Guoyu Ren ◽  
Weidong Liu
Keyword(s):  
Urban Heat Island ◽  
Urban Areas ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Temporal Characteristics ◽  
Seasonal Basis ◽  
Urban Heat ◽  
The City ◽  
Urban Sites ◽  
Spatial And Temporal Characteristics

AbstractAn hourly dataset of automatic weather stations over Beijing Municipality in China is developed and is employed to analyze the spatial and temporal characteristics of urban heat island intensity (UHII) over the built-up areas. A total of 56 stations that are located in the built-up areas [inside the 6th Ring Road (RR)] are considered to be urban sites, and 8 stations in the suburban belts surrounding the built-up areas are taken as reference sites. The reference stations are selected by using a remote sensing method. The urban sites are further divided into three areas on the basis of the city RRs. It is found that the largest UHII generally takes place inside the 4th RR and that the smallest ones occur in the outer belts of the built-up areas, between the 5th RR and the 6th RR, with the areas near the northern and southern 6th RR experiencing the weakest UHI phenomena. On a seasonal basis, the strongest UHII generally occurs in winter and weak UHII is dominantly observed in summer and spring. The UHII diurnal variations for each of the urban areas are characterized by a steadily strong UHII stage from 2100 local solar time (LST) to 0600 LST and a steadily weak UHII stage from 1100 to 1600 LST, with the periods 0600–1100 LST and 1600–2100 LST experiencing a swift decline and rise, respectively. UHII diurnal variation is seen throughout the year, but the steadily strong UHII stage at night is longer (shorter) and the steadily weak UHII stage during the day is shorter (longer) during winter and autumn (summer and spring).

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