Calculating Energy and Its Spatial Distribution for a Subsurface Urban Heat Island Using a GIS-Approach

In urban areas, the human influence on the city-ecosystem often results in a Subsurface Urban Heat Island (SUHI), which can be used geothermally. Unfortunately, a model of a SUHI does not consider the geology and hydrogeology of the subsoil. These can vary significantly over short distances, and are of considerable importance for the energy balance. In this work, we calculated the energy and its density stored in the subsoil via a SUHI. For this so-called energy-SUHI (e-SUHI), we evaluated the geology and its physical parameters for the first 20 m below ground level in the German city of Nuremberg and linked them to measured underground temperatures in a GIS application. This approach revealed stored energy of 1.634 × 1010 MJ within the soil and water for the study area with an area of 163 km2 and a volume of 3.26 × 109 m3. It corresponds to an average energy density of 5.0 MJ/m3. The highest energy density of 16.5 MJ/m3 was found in the city center area and correlated well to increases in subsurface temperature. As expected, our model reacts sensitively to thickness changes in the geological layers and the unsaturated zone.

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Data and techniques for studying the urban heat island effect in Johannesburg

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xl-7-w3-203-2015 ◽

2015 ◽

Vol XL-7/W3 ◽

pp. 203-206 ◽

Cited By ~ 3

Author(s):

C. H. Hardy ◽

A. L. Nel

Keyword(s):

Remote Sensing ◽

Urban Heat Island ◽

Urban Areas ◽

Remote Sensing Data ◽

Urban Heat Island Effect ◽

Heat Island ◽

Sensing Data ◽

Island Effect ◽

Urban Heat ◽

The City

The city of Johannesburg contains over 10 million trees and is often referred to as an urban forest. The intra-urban spatial variability of the levels of vegetation across Johannesburg’s residential regions has an influence on the urban heat island effect within the city. Residential areas with high levels of vegetation benefit from cooling due to evapo-transpirative processes and thus exhibit weaker heat island effects; while their impoverished counterparts are not so fortunate. The urban heat island effect describes a phenomenon where some urban areas exhibit temperatures that are warmer than that of surrounding areas. The factors influencing the urban heat island effect include the high density of people and buildings and low levels of vegetative cover within populated urban areas. This paper describes the remote sensing data sets and the processing techniques employed to study the heat island effect within Johannesburg. In particular we consider the use of multi-sensorial multi-temporal remote sensing data towards a predictive model, based on the analysis of influencing factors.

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How effective is ‘greening’ of urban areas in reducing human exposure to ground-level ozone concentrations, UV exposure and the ‘urban heat island effect’? An updated systematic review

Environmental Evidence ◽

10.1186/s13750-021-00226-y ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Teri Knight ◽

Sian Price ◽

Diana Bowler ◽

Amy Hookway ◽

Sian King ◽

...

Keyword(s):

Urban Heat Island ◽

Urban Areas ◽

Ground Level ◽

Urban Heat Island Effect ◽

Heat Island ◽

Ground Level Ozone ◽

Ozone Concentrations ◽

Island Effect ◽

Green Areas ◽

Urban Heat

Abstract Background This review updates a systematic review published in 2010 (http://www.environmentalevidence.org/completed-reviews/how-effective-is-greening-of-urban-areas-in-reducing-human-exposure-to-ground-level-ozone-concentrations-uv-exposure-and-the-urban-heat-island-effect) which addressed the question: How effective is ‘greening’ of urban areas in reducing human exposure to ground-level ozone concentrations, UV exposure and the ‘urban heat island effect’? Methods Searches of multiple databases and journals for relevant published articles and grey literature were conducted. Organisational websites were searched for unpublished articles. Eligibility criteria were applied at title, abstract and full text and included studies were critically appraised. Consistency checks of these processes were undertaken. Pre-defined data items were extracted from included studies. Quantitative synthesis was performed through meta-analysis and narrative synthesis was undertaken. Review findings 308 studies were included in this review. Studies were spread across all continents and climate zones except polar but were mainly concentrated in Europe and temperate regions. Most studies reported on the impact of urban greening on temperature with fewer studies reporting data on ground-level UV radiation, ozone concentrations (or precursors) or public health indicators. The findings of the original review were confirmed; urban green areas tended to be cooler than urban non-green areas. Air temperature under trees was on average 0.8 °C cooler but treed areas could be warmer at night. Cooling effect showed tree species variation. Tree canopy shading was a significant effect modifier associated with attenuation of solar radiation during the day. Urban forests were on average 1.6 °C cooler than comparator areas. Treed areas and parks and gardens were associated with improved human thermal comfort. Park or garden cooling effect was on average 0.8 °C and trees were a significant influence on this during the day. Park or garden cooling effect extended up to 1.25 kms beyond their boundaries. Grassy areas were cooler than non-green comparators, both during daytime and at night, by on average 0.6 °C. Green roofs and walls showed surface temperature cooling effect (2 and 1.8 °C on average respectively) which was influenced by substrate water content, plant density and cover. Ground-level concentrations of nitrogen oxides were on average lower by 1.0 standard deviation units in green areas, with tree species variation in removal of these pollutants and emission of biogenic volatile organic compounds (precursors of ozone). No clear impact of green areas on ground level ozone concentrations was identified. Conclusions Design of urban green areas may need to strike a balance between maximising tree canopy shading for day-time thermal comfort and enabling night-time cooling from open grassy areas. Choice of tree species needs to be guided by evapotranspiration potential, removal of nitrogen oxides and emission of biogenic volatile organic compounds. Choice of plant species and substrate composition for green roofs and walls needs to be tailored to local thermal comfort needs for optimal effect. Future research should, using robust study design, address identified evidence gaps and evaluate optimal design of urban green areas for specific circumstances, such as mitigating day or night-time urban heat island effect, availability of sustainable irrigation or optimal density and distribution of green areas. Future evidence synthesis should focus on optimal design of urban green areas for public health benefit.

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Changes in Urbanization and Urban Heat Island Effect in Dhaka City

10.21203/rs.3.rs-442136/v1 ◽

2021 ◽

Author(s):

A S M Shanawaz Uddin ◽

Najeebullah Khan ◽

Abu Reza Md. Towfiqul I ◽

Mohammad Kamruzzaman ◽

Shamsuddin Shahid

Keyword(s):

Urban Heat Island ◽

Land Surface ◽

Urban Areas ◽

Clustering Algorithm ◽

Planning Process ◽

Urban Expansion ◽

Heat Island ◽

Dhaka City ◽

Urban Heat ◽

The City

Abstract Urbanization changes the local environment, resulting in urban heat island (UHI) effect and deteriorating human life quality. Knowledge of urban environments and temperature changes is important to outline the urban planning process for mitigation of UHI effect. The study aimed to assess the changes in urban areas and UHI effects in Dhaka city, Bangladesh from 2001to 2017, using Moderate Resolution Imaging Spectroradiometer (MODIS) daily day- and nighttime land surface temperature (LST) data from 2001to 2017. The expansion of the city was calculated using the city clustering algorithm (CCA). The temperature of the identified urbanized area was analyzed and compared with the adjacent regions. The changes in urban temperature were estimated using non-parametric statistical methods. The results showed that the Dhaka city area has grown by 19.12% and its inhabitants by 76.65% during 2001–2017. Urban expansion and dense settlements caused an increase in average temperature in some areas of Dhaka city nearly 3°C compared to that at its boundary. The day and night temperatures at Dhaka city's warmest location were nearly 7 and 5ºC, respectively, more than the coolest point outside the city. The city's annual average day- and nighttime temperature was increasing at a rate of 0.03° and 0.023°C/year over the period 2001–2017. The rising temperature would increase the UHI effect in the future, which combined with high humidity, may cause a significant increase in public health risk in the city if mitigation practices are not followed.

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Analysis of temperature trends and urban heat island in Madrid

10.5194/egusphere-egu2020-10969 ◽

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

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.

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Human thermal comfort in Local climate zones of Berlin

10.5194/egusphere-egu2020-7741 ◽

2020 ◽

Author(s):

Ines Langer ◽

Alexander Pasternack ◽

Uwe Ulbrich

Keyword(s):

Thermal Comfort ◽

Urban Heat Island ◽

Urban Areas ◽

Heat Island ◽

Climate Zones ◽

Local Climate ◽

Human Thermal Comfort ◽

Local Climate Zones ◽

Urban Heat ◽

The City

Urban areas show higher nocturnal temperature comparing to rural areas, which is denoted by urban heat island. This effect can intensify the impact of global warming in urban areas especially during heat waves, that leads to higher energy demand for cooling the building and higher thermal stress for residents.&#160;&#160;The aim of this study is to identify the Urban Heat Island (UHI) effect during the heat spell 2018 and 2019 in order to calculated human thermal comfort for Berlin. Berlin, the capital city of Germany covers an area of 892km2 and its population is growing, therefore more residential areas will be planned in future through higher building. The methodology of this research is to divide Berlin into Local Climate Zones (LCZ's) regarding the concept of Stewart & Oke (2012). Then to evaluate the accuracy of this concept using 30 microclimate stations. Estimating the magnitude of urban heat island and its seasonal changes in combination with human thermal perception in different LCZ during summer time is another objective of this research.&#160;Ten LCZ's for Berlin were selected, as class 1 (compact high rise), class 3 (compact low rise), class 7 (lightweight low-rise), class C (bush, scrub), class E (bare rock or paved) and class F (bare soil or sand) don't exist in Berlin. Class A (dense trees) is with a fraction of 18.6% in a good agreement with the percentage of dense trees reported from the city administration of Berlin (18.4%), class G (water) has a coverage of 5.1% through our classification instead of 6.7% reported by the city administration. In summary, the LCZ 1-10 cover 59.3% (more than half) of the city area.Regarding temperature measurements, which represent a hot summer day with calm wind and clear sky the difference of Local Climate Zones will be calculated and the temperature variability in every LCZ's regarding sky view factor values show the hot spot of the city.The vulnerability of LCZ's to heat stress will be ranked and discussed regarding ventilation and other factors.&#160;LiteratureMatzarakis, A. Mayer, H., Iziomon, M. (1999) Applications of a universal thermal index: Physiological equivalent temperature: Intern. J. of Biomet 43 (2), 76-84.Stewart, I.D., Oke, T.R. (2012) Local climate zones for urban temperature studies. Bull. Amer. Meteor. Soc. 93 1879-1900. DOI: 10.1175/BAMS-D-11-00019.1.&#160;

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Effect of urban geometry and green area on the formation of the urban heat island in Baghdad city

MATEC Web of Conferences ◽

10.1051/matecconf/201816205025 ◽

2018 ◽

Vol 162 ◽

pp. 05025 ◽

Cited By ~ 1

Author(s):

Younis Mohammed ◽

Aws Salman

Keyword(s):

Urban Heat Island ◽

Urban Areas ◽

Research Work ◽

Ambient Air ◽

Width Ratio ◽

Heat Island ◽

Green Area ◽

Urban Geometry ◽

Urban Heat ◽

The City

With the growth of cities, the ambient air temperatures (Ta) inside the urban areas are expected to be higher compared to the surrounding rural areas, creating urban heat island (UHI) phenomenon. The city of Baghdad is an example of a hot dry climate cities and during summer, the UHI intensity is significantly affected by the extreme direct solar radiation and leads to outdoor thermal discomfort. Also it causes an increase in energy consumption and air pollution. This research work focuses on the effect of urban geometry and green area in the formation of heat island through a study of two different fabrics of residential neighbourhoods. The height to width ratio (H/W) and vegetation are adopted while the materials of buildings were unified in all study cases. Three-dimensional numerical software Envi-met 4.1 was utilized to analyze and assess the studied parameters including: ambient air temperature (Ta), street surface temperature (Ts) and mean radiant temperature (Tmrt). This study has given a better understanding of the role of urban geometry and green area on forming the UHI that influence on the microclimatic conditions in hot dry climate of the city of Baghdad. So that helped to generate guidelines of urban design and planning practices for a better thermal performance in hot and dry cities.

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Spatial and Temporal Characteristics of Beijing Urban Heat Island Intensity

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-12-0125.1 ◽

2013 ◽

Vol 52 (8) ◽

pp. 1803-1816 ◽

Cited By ~ 76

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

Jurnal Serambi Engineering ◽

10.32672/jse.v6i1.2608 ◽

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.

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How urbanisation alters the intensity of the urban heat island in a tropical African city

PLoS ONE ◽

10.1371/journal.pone.0254371 ◽

2021 ◽

Vol 16 (7) ◽

pp. e0254371

Author(s):

Xueqin Li ◽

Lindsay C. Stringer ◽

Sarah Chapman ◽

Martin Dallimer

Keyword(s):

Urban Heat Island ◽

Rural Areas ◽

Urban Areas ◽

Heat Island ◽

African City ◽

Local Climate ◽

Urban Cluster ◽

Urban Heat ◽

Management Institutions ◽

The City

Due to the combined effects of urban growth and climate change, rapid urbanisation is particularly challenging in African cities. Areas that will house a large proportion of the urban population in the future coincide with where natural hazards are expected to occur, and where hazard risk management institutions, knowledge, and capacity are often lacking. One of the challenges posed by rapid urbanisation is the Urban Heat Island (UHI) effect, whereby urban areas are warmer than the surrounding rural areas. This study investigates urbanisation patterns and alterations in surface UHI (SUHI) intensity for the Kampala urban cluster, Uganda. Analyses show that between 1995 and 2017, Kampala underwent extensive changes to its urban built-up area. From the centre of the city to adjoining non-built up areas in all directions, the urban land cover increased from 12,133 ha in 1995 to 25,389 ha in 2016. The area of SUHI intensity in Kampala expanded significantly over the 15-year period of study, expanding from 22,910 ha in 2003 to 27,900 ha in 2016, while the annual daytime SUHI of 2.2°C in 2003 had decreased to 1.9°C by 2017. Although SUHI intensity decreased in some parts of the city, elsewhere it increased, suggesting that urbanisation does not always lead to a deterioration of environmental conditions. We postulate that urban development may therefore not necessarily create an undesirable impact on local climate if it is properly managed. Rapidly growing cities in Africa and elsewhere should ensure that the dynamics of their development are directed towards mitigating potentially harmful environmental impacts, such as UHI effect through careful planning that considers both bluespaces and greenspaces.

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