The Hydrological Urban Heat Island: Determinants of Acute and Chronic Heat Stress in Urban Streams

2021 ◽  
Author(s):  
Einara Zahn ◽  
Claire Welty ◽  
James A. Smith ◽  
Stanley J. Kemp ◽  
Mary‐Lynn Baeck ◽  
...  
Keyword(s):  
Heat Stress ◽  
Urban Heat Island ◽  
Urban Streams ◽  
Heat Island ◽  
Urban Heat

scholarly journals Patterns of Urban Heat Island Effect in Adelaide: A Mobile Traverse Experiment

2017 ◽  
Vol 11 (4) ◽  
pp. 80
Author(s):  
Ehsan Sharifi ◽  
Ali Soltani
Keyword(s):  
Heat Stress ◽  
Urban Heat Island ◽  
Urban Policy ◽  
Urban Heat Island Effect ◽  
Urban Structure ◽  
Heat Island ◽  
Near Surface ◽  
Island Effect ◽  
Urban Rural ◽  
Urban Heat

Urban structure, hard surfaces and shortage of vegetation cause an artificial temperature increase in cities, known as the urban heat island effect. This paper determines the daily patterns of urban heat in Adelaide, Australia. The near-surface temperature profile of Adelaide was mapped in 60 journeys alongside a straight cross route connecting Adelaide Hills to the West Beach between 26 July and 15 August 2013. Results indicate that the most intense urban-rural temperature differences occurred during midnight in Adelaide. However, the afternoon urban heat had more temperature variation in the urban area. In the late afternoon, the near-surface urban heat fluctuates by 2°C within three kilometres and by 1.2°C in just one kilometer. Afternoon heat stress can vary based on space configurations and urban surface covers. Afternoon heat stress causes the highest heat load on urban dwellers. A better understanding of daily urban heat variations in cities assists urban policy making and public life management in the context of climate change.

Urban Informal Housing and Surface Urban Heat Island Intensity

2018 ◽  
Vol 9 (2) ◽  
pp. 158-177 ◽  
Author(s):  
Surabhi Mehrotra ◽  
Ronita Bardhan ◽  
Krithi Ramamritham
Keyword(s):  
Heat Stress ◽  
Spatial Analysis ◽  
Urban Heat Island ◽  
Urban Form ◽  
Spatial Association ◽  
Heat Island ◽  
Urban Heat ◽  
Surface Urban Heat Island ◽  
The Impact ◽  
Slum Housing

Urbanization leads to the densification of built-up areas, and thereby increases surface heat island intensity which is one of the growing concerns in the rapidly urbanizing cities. Another notable aspect of cities like Mumbai is the uncontrolled growth of informal slum housing clusters, which have emerged as a significant urban built form in the landscape of cities. This study presents a case of Mumbai that aims to explore the linkages between slum housing—here referred as ‘slum urban form’ (SUF)—and surface urban heat island (SUHI) supported by spatial-statistical analysis. The magnitude of the impact of urban form on SUHI, measured by land surface temperature (LST), is examined using Cohen’s d index, which measures the effect size for two groups—SUF and ‘formal’ housing—on LST. The results confirm a ‘large’ effect indicating a significant difference in mean LST between the two groups. The spatial analysis reveals a statistically significant spatial clustering of LST and SUF ( p-value < 0.05), and bivariate local indicator of spatial association (LISA) confirms that the spatial association of SUF is surrounded by ‘high’ LST (Moran I: 0.49). The exploratory spatial analysis indicates that the contribution of SUF in elevating SUHI intensity is more than the formal housing areas and has increased vulnerability to heat stress. The results were validated on the ground using environmental sensors, which confirms the susceptibility of SUF to heat stress.

Understanding and Analysing the Urban Heat Island (UHI) Effect in Micro-Scale

2019 ◽  
Vol 10 (2) ◽  
pp. 14-28 ◽  
Author(s):  
Ali Soltani ◽  
Ehsan Sharifi
Keyword(s):  
Heat Stress ◽  
Surface Temperature ◽  
Urban Heat Island ◽  
Metropolitan Area ◽  
Urban Environments ◽  
Heat Island ◽  
Late Afternoon ◽  
Micro Scale ◽  
Daily Cycles ◽  
Urban Heat

The shortage of vegetation cover alongside urban structures and land hardscape in cities causes an artificial temperature increase in urban environments known as the urban heat island (UHI) effect. The artificial heat stress in cities has a particular threat for usability and health-safety of outdoor living in public space. Australia may face a likely 3.8°C increase in surface temperature by 2090. Such an increase in temperature will have a severe impact on regional and local climate systems, natural ecosystems, and human life in cities. This paper aims to determine the patterns of the UHI effect in micro-scale of Adelaide metropolitan area, South Australia. The urban near-surface temperature profile of Adelaide was measured along a linear east-west cross-section of the metropolitan area via mobile traverse method between 26 July 2013 and 15 August 2013. Results indicate that the while the maximum UHI effect occurs at midnight in the central business district (CBD) area in Adelaide, the afternoon urban warmth has more temperature variations (point-to-point variation), especially during the late afternoon when local air temperature is normally in its peak. Thus, critical measurement of heat-health consequences of the UHI effect need to be focused on the afternoon heat stress conditions in UHIs rather than the commonly known night time phenomenon. This mobile traverse urban heat study of Adelaide supports the hypothesis that the UHI effect varies in the built environment during daily cycles and within short distances. Classical UHI measurements are commonly performed during the night – when the urban-rural temperature differences are at their maximum. Thus, they fall short in addressing the issue of excess heat stress on human participants. However, having thermally comfortable urban microclimates is a fundamental characteristic of healthy and vibrant public spaces. Therefore, urban planning professionals and decision makers are required to consider diurnal heat stress alongside nocturnal urban heat islands in planning healthy cities. The results of this article show that the diurnal heat stress varies in the built environment during daily cycles and within short distances. This study confirms that the maximum urban heat stress occurs during late afternoon when both overall temperature and daily urban warmth are at their peak. Literature indicates that diurnal heat stress peaks in hard-landscapes urban settings while it may decrease in urban parklands and near water bodies. Therefore, urban greenery and surface water can assist achieving more liveable and healthy urban environments (generalisation requires further research). A better understanding of daily urban warmth variations in cities assists urban policy making and public life management in the context of climate change.

scholarly journals Evaluating the Effectiveness of Mitigation Options on Heat Stress for Sydney, Australia

2018 ◽  
Vol 57 (2) ◽  
pp. 209-220 ◽  
Author(s):  
Shaoxiu Ma ◽  
Andy Pitman ◽  
Jiachuan Yang ◽  
Claire Carouge ◽  
Jason P. Evans ◽  
...  
Keyword(s):  
Heat Stress ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Ambient Air ◽  
Mitigation Strategies ◽  
Heat Island ◽  
Human Thermal Comfort ◽  
Ambient Air Temperature ◽  
Populations At Risk ◽  
Urban Heat

AbstractGlobal warming, in combination with the urban heat island effect, is increasing the temperature in cities. These changes increase the risk of heat stress for millions of city dwellers. Given the large populations at risk, a variety of mitigation strategies have been proposed to cool cities—including strategies that aim to reduce the ambient air temperature. This paper uses common heat stress metrics to evaluate the performance of several urban heat island mitigation strategies. The authors found that cooling via reducing net radiation or increasing irrigated vegetation in parks or on green roofs did reduce ambient air temperature. However, a lower air temperature did not necessarily lead to less heat stress because both temperature and humidity are important factors in determining human thermal comfort. Specifically, cooling the surface via evaporation through the use of irrigation increased humidity—consequently, the net impact on human comfort of any cooling was negligible. This result suggests that urban cooling strategies must aim to reduce ambient air temperatures without increasing humidity, for example via the deployment of solar panels over roofs or via cool roofs utilizing high albedos, in order to combat human heat stress in the urban environment.

scholarly journals Global long-term mapping of surface temperature shows intensified intra-city urban heat island extremes

2021 ◽  
Author(s):  
Lorenzo Mentaschi ◽  
Gregory Duveiller ◽  
Grazia Zulian ◽  
Christina Corbane ◽  
Martino Pesaresi ◽  
...  
Keyword(s):  
Heat Stress ◽  
Surface Temperature ◽  
Urban Heat Island ◽  
Urban Areas ◽  
Human Impacts ◽  
Warm Season ◽  
Mitigation Strategies ◽  
Heat Island ◽  
Urban Heat

Abstract Surface temperatures are generally higher in cities than in rural surroundings. This phenomenon, known as surface urban heat island (SUHI), increases the risk of heat-related human illnesses and mortality. Past global studies analysed this phenomenon aggregated at city scale or over seasonal and annual time periods, while human impacts strongly depend on shorter term heat stress experienced locally. Here we develop a global long-term high-resolution dataset of daytime SUHI as urban-rural surface temperature differences. Our results show that across urban areas worldwide over the period 2003-2020, 3-day SUHI extremes are on average more than twice as high as the warm-season median SUHI, with local exceedances up to 10 K. Over this period, SUHI extremes have increased more rapidly than warm-season medians, and averaged worldwide are now 1.04 K or 31% higher compared to 2003. This can be linked with increasing urbanisation, more frequent heatwaves, and greening of the earth, processes that are all expected to continue in the coming decades. Within many cities there are hotspots where extreme SUHI intensity is 10 to 15 K higher compared to relatively cooler city parts. Given the limited human adaptability to heat stress, our results advocate for mitigation strategies targeted at reducing SUHI extremes in the most vulnerable and exposed city neighbourhoods.

scholarly journals Quantitative Evaluation of Urban Heat Island Mitigation Effect and Reduction Human Heat Stress by Large Greening of Roof

2008 ◽  
Vol 64 (4) ◽  
pp. 257-270 ◽  
Author(s):  
Naru TAKAYAMA ◽  
Haruhiko YAMAMOTO ◽  
Kiyoshi IWAYA ◽  
Wang FEI ◽  
Yoko HARADA ◽  
...  
Keyword(s):  
Heat Stress ◽  
Urban Heat Island ◽  
Quantitative Evaluation ◽  
Heat Island ◽  
Urban Heat

scholarly journals Heat Stress and Vulnerability

2020 ◽  
Author(s):  
Bhupesh Upadhyay
Keyword(s):  
Heat Stress ◽  
Urban Heat Island ◽  
Health Effects ◽  
Heat Stroke ◽  
Heat Island ◽  
Health Issues ◽  
Respiratory Problems ◽  
Temperature Heat ◽  
Urban Heat ◽  
Related Mortality

With the rising global temperature heat stress is emerging as a major issue. Exposure of humans in a warmer temperature is affecting the health and the productivity. On an average, 5-6 heat wave events occur every year over the northern parts of India. Most cities in India are turning into Urban Heat Island and becoming a major risk for health issues like respiratory problems, heat cramps and exhaustion's, heat stroke and heat related mortality. This study examined the most vulnerable population due to heat stress and the health effects. Formation of Urban Heat Island is also reviewed.

Analisis Pengaruh Kerapatan Vegetasi Terhadap Suhu Permukaan dan Keterkaitannya Dengan Fenomena UHI

2020 ◽  
Vol 21 (1) ◽  
pp. 99
Author(s):  
Dewi Miska Indrawati ◽  
Suharyadi Suharyadi ◽  
Prima Widayani
Keyword(s):  
Urban Heat Island ◽  
Landsat 8 ◽  
Heat Island ◽  
Landsat 8 Oli ◽  
Urban Heat ◽  
Split Window Algorithm

Kota Mataram adalahpusat dan ibukota dari provinsi Nusa Tenggara Barat yang tentunya menjadi pusat semua aktivitas masyarakat disekitar daerah tersebut sehingga menyebabkan peningkatan urbanisasi. Semakin meningkatnya peningkatan urbanisasi yan terjadi di perkotaan akan menyebabkan perubahan penutup lahan, dari awalnya daerah bervegetasi berubah menjadi lahan terbangun. Oleh karena itu, akan memicu peningkatan suhu dan menyebabkan adanya fenomena UHI dikota Mataram.Tujuan dari penelitian ini untuk mengetahui hubungan kerapatan vegetasi dengan kondisi suhu permukaan yang ada diwilayah penelitian dan memetakan fenomena UHI di Kota Mataram. Citra Landsat 8 OLI tahun 2018 yang digunakan terlebih dahulu dikoreksi radiometrik dan geometrik. Metode untuk memperoleh data kerapatan vegetasi menggunakan transformasi NDVI, LST menggunakan metode Split Window Algorithm (SWA) dan identifikasi fenomena urban heat island. Hasil penelitian yang diperoleh menunjukkan kerapatan vegetasi mempunyai korelasi dengan nilai LST. Hasil korelasi dari analisis pearson yang didapatkan antara kerapatan vegetasi terhadap suhu permukaan menghasilkan nilai -0,744. Fenomena UHIterjadi di pusat Kota Mataram dapat dilihat dengan adanya nilai UHI yaitu 0-100C. Semakin besar nilai UHI, semakin tinggi perbedaan LSTnya.

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