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Effect of Heat Islands over Urban Madras and measures for its mitigation
Abstract
In India the study of urban climate and its influences on urban planning and building climatology is a newly emerging area for detailed studies. This vast inter-disciplinary study encompasses such disciplines as meteorology, urban planning, architecture, building physics, landscape, land-use studies using remote-sensing, etc.This paper will discuss a heat island case study over urban Madras and its neighbourhood based on surface temperature, humidity and wind data collected from 77 points using mobile observations. Besides these measurements, additional information about the three-dimensional structure of the temperature distribution from special radiosonde-radiowind ascents was also taken in two observatories representing suburban and urban areas of the metropolis. The paper will also broadly discuss the mitigation measures and the future line of action of research in the area of urban climate and building climatology in India.
... The measurement of heat island can be carried out in five different ways such as fixed stations, mobile traverses (Brandsma and Wolters 2012;Sundersingh 1990), remote sensing, vertical sensing, and energy balances. The most common method of measuring heat islands is by comparing existing data from two or more fixed stations (Gartland 2012). ...
... Hereafter, many studies were carried out across India in different periods. However, only a few UHI (Amirtham and Monsingh 2008;Amirtham 2016;Amirtham et al. 2009;Jayanthi 1991;Sundersingh 1990) studies were noted in southern part of India, Chennai, by using in situ measurements. Chennai is one of the highly populated metropolitan cities in India. ...
... Similar studies have been carried out in the study area Chennai during the years 1988 (Jayanthi 1991), 1991 (Sundersingh 1990), 2003(Gopalakrishnan et al. 2003), 2008(Amirtham and Monsingh 2008, and (Amirtham 2016). The result of the analysis by Jayanthi (1991) conveys that UHI existence with maximum intensity changes by 4°C in the industrial zones Mambalam, Vepery, and Ennore. ...
Mounting human population and fast urban expansion has driven the ecosystem degradation within the past 3 decades by reducing permeable cultivable land surface for the construction and thus increasing land surface temperature (LST) and creating urban heat islands (UHI). It is well known that temporal assessment of land surface temperature and UHI are inevitable for city planning and ecosystem monitoring. Landsat-derived LST is widely used for urban temperature studies including the study of the urban heat island (UHI). In this study, remote sensing (RS) techniques have been used for the estimation and forecasting of LST and identification of UHI in one of the fast-growing cities of Tamil Nadu state, India, using Autoregressive Integrated Moving Average (ARIMA) model. Satellite data between the period 2008 and 2018 was used in the model study. Analysis of the images and model results show that there is a progressive increasing trend of LST in built-up areas. LST values obtained from model study exhibited a negative relationship with land use and land cover (LULC) for Chennai city and surrounding area. LST maps developed from the model study depicted growing UHI hotspots in the southeastern and western parts of the city where the development of the city is fast. The present study would help in forecasting the LST of a city and in identifying UHI hotspots for proper urban planning.
... Pioneers in the field of UHI used field measurements with thermometers ( (Sundersingh, 1990), (Jayanthi, 1991)) and mobile observation to collect data that was fairly well distributed all over the research area. These measurements were then extrapolated to obtain complete details of the field. ...
... Early studies in the erstwhile Madras ( (Sundersingh, 1990), (Jayanthi, 1991)) utilized mobile observations and other studies also used data from the meteorological weather stations ( (Mohan et al., 2012), (Maral & Mukhopadhyay, 2015)). The authors combined both mobile observations and meteorological data to map the UHI and observed that the heat islands are mainly situated in densely populated commercial and industrial areas. ...
With an estimated population of about 6 billion living in urban areas by 2050, controlling the rate of urbanization is one of the major challenges governments face in the twenty-first century. Increasing urbanization is problematic since it causes heat accumulation within urban areas due to the enhanced anthropogenic activities. With developing countries like India aiming for their economic growth, combating urban heat islands (UHIs) is a critical step in improving the quality of life. Efficient mitigation of UHI effects requires accurate mapping and monitoring, which can be enhanced through the use of machine learning and deep learning algorithms. This paper provides a critical review of UHI mapping approaches employed globally, with a particular emphasis on the Indian region along with a focus on AI-based methods. Key issues, challenges, and future research directions are also discussed.
... Especially forChennai, which is a tropical city that is going to expand to three times its current size [1]. At its existing size, Chennai is already vulnerable to urban heat and the phenomena of Urban Heat Islands (UHIs) due to rapid urbanization [2,3]. There is an instant requirement to conduct research and formulate a proactive approach in dealing with urban heat and the stresses on urban quality of life it generates. ...
... There is an instant requirement to conduct research and formulate a proactive approach in dealing with urban heat and the stresses on urban quality of life it generates. Most studies and research done on UHI is a reactive study [2,4]. Post urbanisation and generation UHIs or heat pockets, research is conducted to identify the heat pockets, study the various parameters causing the heat pockets and the intensity of the heat pockets, and mitigation measures are IOP Publishing doi: 10.1088/1755-1315/1210/1/012038 2 suggested. ...
A tropical Chennai city, is already enduring heat stresses in its urban areas and is extremely vulnerable to temperature rise. Furthermore, Chennai continues to expand, thus the need to conduct research and make informed decisions on sensible strategies and regulations on how to construct and with what to construct attains much significance in recent times. One of the major contributors to the urban heat is the materials used on the surfaces of the urban form. The current paper assesses and demonstrates the performance of two wall materials – Clay Brick and AAC, usually utilized in urban developments within the context of an optimal urban morphological region. This is accomplished by making a compact mid-rise urban form of residential typology and utilizing ENVI-met 4.0 and re-creating the outdoor microclimatic conditions with AAC and Clay Brick walls. The urban form created with the Clay brick walls are found to be cooler by 0.010°C. Compared to daytime, at night time, the outside air temperature with clay brick walls and AAC dividers are cooler respectively. This investigation additionally discovered that a huge distinction to outside air temperature for studied urban form structure can be made by expanding the Sky View Factor (SVF), contrasted with an adjustment of material. The understandings from this study can be expanded and be applied productively to impact changes in Urban development guidelines.
... In 1833, Howard [7] initially presented the idea of UHI; UHI is a phenomenon in which the temperatures of urban areas are more than the temperature of its associated rural areas [8]. In recent decades, a large number of researchers have studied the negative effects of UHI on human life, ecosystem, reduction of biodiversity [9], climate change [10], destruction of vegetation [11], increase in the rate of disease and mortality [12], and reduction in water and air quality [13]. ...
... Five different methods, including fixed stations, remote sensing, mobile traverses [12,13], vertical sensing, and energy balances, can be used to measure the two types of UHI: (1) atmospheric UHI (AUHI) and (2) surface UHI (SUHI) [14]. AUHI utilized temperature data from ground weather stations [15]; all over the world, weather stations are unevenly distributed and they are very few in numbers, which causes the low observation density of results [16]. ...
In the context of rapid urbanization, Urban Heat Island (UHI) is considered as a major anthropogenic alteration in Earth environments, and its temporal trends and future forecasts for large areas did not receive much attention. Using land surface temperature (LST) data from MODIS (Moderate Resolution Imaging Spectro-radiometer) for years 2006 to 2020, we quantified the temporal trends of daytime and nighttime surface UHI intensity (SUHII, difference of urban temperature to rural temperature) using the Mann-Kendall (MK) trend test in six major cities of the Punjab province of Pakistan and estimated the future SUHII for the year 2030 using the ARIMA model. Results from the study revealed that the average mean SUHII for daytime was noted as 2.221 °C and the average mean nighttime SUHII was noted as 2.82 °C for the years 2006 to 2020. The average mean SUHII for daytime and nighttime exhibited increasing trends for all seasons and annually, and for the daytime spring season it showed a maximum upward trend of 0.486 °C/year (p < 0.05) and for the nighttime annual SUHII with an increasing rate of 0.485 °C/year (p < 0.05) which exhibited a maximum upward trend. The ARIMA model forecast suggested an increase of 0.04 °C in the average daytime SUHII and an increase of 0.1 °C in the average nighttime SUHII until 2030. The results from this study highlight the increasing trends of daytime and nighttime SUHII, ARIMA also forecasted an increase in daytime and nighttime SUHII, suggesting various strategies are needed for an effective mitigation of the UHI effect.
... In Period-1 (Fig. 3), the main research areas were construction building technology, energy fuels, civil engineering, meteorology atmospheric sciences, and environmental sciences. Such research areas are primarily relevant to innovative building materials (e.g., reflective materials) [72], heat island causes, effects, and mitigation solutions [73][74][75], and microclimate regulation strategies [76]. The areas of geography and physics indicated the studies on urban meteorology [72,[77][78][79], and the areas of urban studies and regional urban planning showed the research scope and planning purpose (e.g., urban form, landscape) for investigation [80]. ...
This paper presents a bibliometric review of the history and evolution of Urban Heat Mitigation and Adaptation (UHMA) from 1989 to 2021 to identify research progress, knowledge gaps, and future research directions. The results indicate that research on UHMA is booming and that the field has diversified over time. Existing studies have examined UHMA from the environmental, technical, health, economic, and social perspectives. Over time, UHMA has evolved into a transdisciplinary research field, covering many emerging areas beyond built environments, including materials, computer sciences, physiology, chemistry, and geosciences. Relevant UHMA topics can be divided into four research clusters: (i) UHI impact assessment and cause identification, (ii) microclimate regulation and human thermal comfort, (iii) climate-related health impact and adaptation, and (iv) urban heat mitigation strategies and techniques. This study highlights some knowledge gaps in UHMA research, including (i) overfocusing on urban heat causes, effects, and mitigation solutions; (ii) more focus on mitigation, overshadowing adaptation, and preparation; (iii) highlighting materials and vegetation, but overlooking water features and urban form; (iv) incomplete understanding of heat-related impacts; (v) focusing more on microclimate and heat islands rather than extreme heat; (vi) unsound policy, social, and economic support; and (vii) lack of actual UHMA implementation. There are also some challenges in UHMA development, including (i) the uneven distribution of publications, authors, and affiliations; (ii) topic, affiliation, and nation aggregation and bias; (iii) slow evolution in key disciplines, publications, and authors; (iv) knowledge isolation owing to tendentious academic collaboration and communication; and (v) limited journal scope and restricted methodological approaches. To overcome such challenges and enhance UHMA research and policy, 13 suggestions were made. Overall, by promoting trans-disciplinary UHMA research informed by climatic sciences, scientific models, policy-relevant techniques, and socio-economic support, this study is expected to better frame UHMA research and bridge science and policy.
... All these studies have documented profound impact of urbanization on climate of tropical cities by identifying a strong heat island over the city region. However, there is not much literature on Indian UHI studies from late 1980 to 2000s except for Sundersingh (1990) for Chennai city (erstwhile Madras), Padmanabhamurty (1990) for Delhi, and few studies for Pune (Mukherjee et al., 1987;Gadgil and Deosthali, 1994;Deosthali, 2000). All these studies measured canopy layer heat island in their respective study areas. ...
Research for urban heat island (UHI) in India has accelerated in past few years covering not only megacities but small towns as well. This chapter presents a discussion on the UHI scenario in India, which is the second largest populated country and one of the top growing economies in the world. It examines UHI quantification across India from multiple assessment methods, possible impacts, mitigation strategies and finally, identifies future research directions. In India, UHI intensities up to 8–10°C have been reported in areas with dense urban and commercial pockets. The varied methods of determination of UHI (such as fixed instruments, mobile surveys, and satellite-derived measurements) at surface and canopy layer are discussed while noting the paucity of research for the boundary layer UHI in India. Measurements alone are not adequate due to limitations of instrumental installation and errors and spatiotemporal continuity. Hence, mathematical tools such as empirical models and numerical mesoscale weather prediction models are used to understand the UHI phenomenon at region of interest, assess major causative factors, and design mitigation strategies. Case studies of such model applications are presented in this chapter. UHI effect has shown significant implications on spatiotemporal rainfall patterns, perceived thermal comfort, and heat-related morbidity and mortality for Indian cities. The review brings out emergence of concepts such as regional heat island and UHI based on local climate zones. Efficacy of various mitigation measures such as increasing green cover/plantation, thermally resistant building materials, reflective coating, etc., on surfaces is discussed in detail. The comprehensive review of different aspects of UHI in this chapter should help the scientific community as well as the regulatory bodies to determine future research focus and action plans with regard to UHI effect, its impact and mitigation in India.
... Few studies that are conducted in Chennai focused on UHI investigation using mobile traverses. In an early study conducted in 1987, Sundersingh [23] used mobile traverses to collect temperature, humidity and wind data from 77 locations in Chennai using three routes. The difference between cool pockets and heat islands ranged from 2.5 to 4°C. ...
Urban heat island (UHI) studies using ground-based observations are limited in the tropical cities of India. This chapter reviews the UHI studies in the tropical cities located in the southern and central states of the subcontinent, namely Tamil Nadu, Karnataka, Kerala and Maharashtra. In tropical cities that experience high latent heat fluxes, the thermal environments are also affected by the heterogenous nature of urban settings. Majority of the UHI studies were conducted for a short period using either non-standard stations or mobile surveys, or a combination of these, with the reported UHI intensities ranging from 1.76 to 4.6 °C. Comparison between studies are difficult due to the variation in the methodology and the way results are presented. Ground-based measurements deployed in both micro and macro scales informed by high resolution remote sensing outputs will help to address the gap in the current knowledge. Dense network of stations installed using crowd sourcing approach are proven to be beneficial if uncertainties are carefully addressed. This chapter also discusses the application of UHI mitigation strategies established in similar climatic conditions and land use patterns. Mitigation actions including tree planting, use of appropriate materials as well as enhancing ventilation should be carefully chosen according to the geometry and orientation of the streets.
Chennai city is the capital of Tamil Nadu, located in the Southeastern India. The
average population growth of the city is 25% per decade, which recurrently reduces the
green-covered area. Exceptionally, during the post-economic liberalization period, i.e.
between the years 1997-2001, the city lost up to 99% of its green-covered areas in some
parts. Subsequently, Chennai city started to experience a wide range of environmental
issues, like urban heat islands, pollution, groundwater depletion, etc. Though other
factors are also the reason for that, the receding green covers mainly lower the urban
system's self-rejuvenation capacity. In other words, the diminishing green-covers
simplified many aspects of the natural process, thus ultimately affecting Chennai
city's environmental performance. To appraise this sensitive association between the
green cover and the city's environmental performance, a GIS model has been developed.
The model is evolved using the three sets of green-cover services, namely the air
quality amelioration, the hydrological process regulation, and the micro-climatic
amelioration. Through this model, the correlation between Chennai city's green cover
change and its environmental performance change is appraised. The output
confirms the positive relationship between per capita green cover modification and the
Chennai City's environmental performance change. The result also shows that the
Chennai city's environmental performance was reduced drastically across the city
between the years 1997- 2001, at some parts to the degree of 38%.
Urban heat island is a phenomenon affecting cities across the world. While in cold climates it could be regarded as an even beneficious process, in temperate climates and especially in the inter-tropical latitude range, the increase in urban temperature can generate risks for health, outdoor and indoor discomfort, and an increase in buildings energy needs. This chapter provide a state of art review of UHI studies conducted recently in Latin-American area, with special focus on tropical climate cities. First step is determining which big Latin-American cities are placed in tropical or subtropical climates. Then, Journals articles, Book Chapters and Proceedings are investigated to establish the state of art, putting in evidence which kind of methods are used in determining UHI intensities, which impacts are searched, and which mitigation strategies are proposed.
Mobile temperature surveys were conducted in Delhi during the winter months in the early hours m of 18 December 1976,29 Jauary1977, 26 February 1977 and 26 March1977. The surveys show the formation of heat island within the thickly populated walled city encompassing areas from Delhi Gate, Chandni Chowk to Ajmeri Gate. Secondary, Heat Island in the trans-Yamuna area and near Y usaf Sarai area in South Delhi are also found. The maximum temperature difference between the warmest part of the city and the coldest area of the suburb was nearly 5°C during December which increased to nearly 7°C in the months January to March.
Delhi exhibited several small warm pockets due to agglomeration of houses in 30. colonies interspersed by green vegetation, open areas, wide roads, parks and maidans etc. Two peaks of heat island intensity were observed -one in the early night and another in the early morning. The early morning heat island is stronger than the early night. Humidity islands exhibited inverse relation to heat islands wherever moisture is not available but followed heat islands in intensity where moisture is available. Humidity islands also exhibited two peaks similar to heat islands. The early morning peak was in phase with heat island but the early night peak is out of phase. The thermal radiant emittance from different surfaces in Delhi like green areas, concrete roads, tar roads, built-up areas are found to be responsible for the formation of several warm pockets instead of a single intense heat island.
A mobile temperature survey of Bombay and Greater Bombay was conducted in the early hours of 11 January 1975. The survey shows a 'heat Island' over the Malabar Hill, Girgaum and Cuffee Parade area with a maximum temperature difference of about 11° between the urban and the almost rural suburbs. The horizontal temperature distribution is found to be influenced by proximity to the sea, concentration of population, tall buildings and industry and the prevailing wind field. Vertical temperature profile measurements over the Worli Television tower indicate the top of presumably the first inversion layer in this area to be around 127 m on this day.
Results of two temperature mobile surveys conducted during clear, calm winter nights at Pune are presented. Warm pockets existed wherever agglomeration of buildings existed. Twin heat islands are noticed in Pune on either side of the river. Isohumes followed the same pattern of isotherms except vice versa in magnitudes. Isohumes and isotherms exhibited double peaks-one, four hours after sunset and another at the minimum temperature epoch.