scholarly journals Evaluation of Urban Heat Island (UHI) Using Satellite Images in Densely Populated Cities of South Asia

Earth ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 86-110
Author(s):  
Manisha Maharjan ◽  
Anil Aryal ◽  
Bijay Man Shakya ◽  
Rocky Talchabhadel ◽  
Bhesh Raj Thapa ◽  
...  

Rapid Urbanization, and other anthropogenic activities, have amplified the change in land-use transition from green space to heat emission in built-up areas globally. As a result, there has been an increase in the land surface temperature (LST) causing the Urban Heat Island (UHI) effect, particularly in large cities. The UHI effect poses a serious risk to human health and well-being, magnified in large developing cities with limited resources to cope with such issues. This study focuses on understanding the UHI effect in Kathmandu Valley (KV), Delhi, and Dhaka, three growing cities in South Asia. The UHI effect was evaluated by analyzing the UHI intensity of the city with respect to the surroundings. We found that the central urban area, of all three cities, experienced more heat zones compared to the peri-urban areas. The estimated average surface temperature ranged from 21.1 ∘C in March 2014 to 32.0 ∘C in June 2015 in KV, while Delhi and Dhaka experienced surface temperature variation from 29.7 ∘C in June 2017 to 40.2 ∘C in June 2019 and 23.6 ∘C in March 2017 to 33.2 ∘C in March 2014, respectively. Based on magnitude and variation of LST, highly built-up central KV showed heat island characteristics. In both Delhi and Dhaka, the western regions showed the UHI effect. Overall, this study finds that the UHI zones are more concentrated near the urban business centers with high population density. The results suggest that most areas in these cities have a rising LST trend and are on the verge of being UHI regions. Therefore, it is essential that further detailed assessment is conducted to understand and abate the impact of the temperature variations.

Author(s):  
Van Tran Thi ◽  
Bao Ha Duong Xuan ◽  
Mai Nguyen Thi Tuyet

In urban area, one of the great problem is the rise of temperature, which leads to form the urban heat island effect. This paper refers to the trend of the urban surface temperature extracted from the Landsat images from which to consider changes in the formation of surface urban heat island for the north of Ho Chi Minh city in period 1995-2015. Research has identified land surface temperature from thermal infrared band, according to the ability of the surface emission based on characteristics of normalized difference vegetation index NDVI. The results showed that temperature fluctuated over the city with a growing trend and the gradual expansion of the area of the high-temperature zone towards the suburbs. Within 20 years, the trend of the formation of surface urban heat island with two typical locations showed a clear difference between the surface temperature of urban areas and rural areas with space expansion of heat island in 4 times in 2015 compared to 1995. An extreme heat island located in the inner city has an area of approximately 18% compared to the total area of the region. Since then, the solution to reduce the impact of urban heat island has been proposed, in order to protect the urban environment and the lives of residents in Ho Chi Minh City becoming better


2021 ◽  
Vol 13 (18) ◽  
pp. 3684
Author(s):  
Yingying Ji ◽  
Jiaxin Jin ◽  
Wenfeng Zhan ◽  
Fengsheng Guo ◽  
Tao Yan

Plant phenology is one of the key regulators of ecosystem processes, which are sensitive to environmental change. The acceleration of urbanization in recent years has produced substantial impacts on vegetation phenology over urban areas, such as the local warming induced by the urban heat island effect. However, quantitative contributions of the difference of land surface temperature (LST) between urban and rural (ΔLST) and other factors to the difference of spring phenology (i.e., the start of growing season, SOS) between urban and rural (ΔSOS) were rarely reported. Therefore, the objective of this study is to explore impacts of urbanization on SOS and distinguish corresponding contributions. Using Hangzhou, a typical subtropical metropolis, as the study area, vegetation index-based phenology data (MCD12Q2 and MYD13Q1 EVI) and land surface temperature data (MYD11A2 LST) from 2006–2018 were adopted to analyze the urban–rural gradient in phenology characteristics through buffers. Furthermore, we exploratively quantified the contributions of the ΔLST to the ΔSOS based on a temperature contribution separation model. We found that there was a negative coupling between SOS and LST in over 90% of the vegetated areas in Hangzhou. At the sample-point scale, SOS was weakly, but significantly, negatively correlated with LST at the daytime (R2 = 0.2 and p < 0.01 in rural; R2 = 0.14 and p < 0.05 in urban) rather than that at nighttime. Besides, the ΔSOS dominated by the ΔLST contributed more than 70% of the total ΔSOS. We hope this study could help to deepen the understanding of responses of urban ecosystem to intensive human activities.


Climate ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 71
Author(s):  
Priyanka Kumari ◽  
Sukriti Kapur ◽  
Vishal Garg ◽  
Krishan Kumar

Rapid urbanization and associated land-use changes in cities cause an increase in the demand for electricity by altering the local climate. The present study aims to examine the variations in total energy and cooling energy demand in a calibrated building energy model, caused by urban heat island formation over Delhi. The study used Sentinel-2A multispectral imagery for land use and land cover (LULC) of mapping of Delhi, and Moderate Resolution Imaging Spectroradiometer (MODIS) imagery for land surface temperature (LST) mapping during March 2018. It was observed that regions with dense built-up areas (i.e., with built-up area greater than 90%) had a higher annual land surface temperature (LST), i.e., 293.5 K and urban heat island intensity (UHII) ranging from 0.9 K–5.9 K. In contrast, lower annual values of LST (290K) and UHII (0.0–0.4 K) were observed in regions with high vegetation cover (53%). Statistical analysis reveals that a negative correlation exists between vegetation and nighttime LST, which is further confirmed by linear regression analysis. Energy simulations were performed on a calibrated building model placed at three different sites, identified on the basis of land use and land cover percentage and annual LST. Simulation results showed that the site located in the central part of Delhi displayed higher annual energy consumption (255.21 MWh/y) compared to the site located in the rural periphery (235.69 MWh/y). For all the three sites, the maximum electricity consumption was observed in the summer season, while the minimum was seen in the winter season. The study indicates that UHI formation leads to increased energy consumption in buildings, and thus UHI mitigation measures hold great potential for energy saving in a large city like Delhi.


2020 ◽  
Vol 12 (3) ◽  
pp. 1171 ◽  
Author(s):  
Hongyu Du ◽  
Fengqi Zhou ◽  
Chunlan Li ◽  
Wenbo Cai ◽  
Hong Jiang ◽  
...  

In the trend of global warming and urbanization, frequent extreme weather influences the life of citizens seriously. Shanghai, as a typical mega-city in China that has been successful in urbanization, suffers seriously from the urban heat island (UHI) effect. The research concentrates on the spatial and temporal pattern of surface UHI and land use. Then, the relation between them are further discussed. The results show that for the last 15 years, the UHI effect of Shanghai has been increasing continuously in both intensity and area. The UHI extends from the city center toward the suburban area. Along with the year, the ratio in area of Agricultural Land (AL), Wetland (WL), and Bare Land (BL) has decreased. On the contrary, Construction Land (CL) and Green Land (GL) have increased. The average land surface temperature (LST) rankings for each research year from high to low were all CL, BL, GL, AL, and WL. CL contributed the most to the UHI effect, while WL and GL contributed the most to mitigate the UHI. The conclusion provides practical advice aimed to mitigate the UHI effect for urban planning authorities.


Author(s):  
A. Galodha ◽  
S. K. Gupta

Abstract. At least 2 billion urban occupants will be concentrated in Asia and Africa, amounting to 70% of the global population by 2050. This rapid urbanization has caused an innate effect on the ecology and environment, which further results in intense temperature variations in urban and rural areas, especially in India. According to a recent IPCC report, 8 out of the 15 hottest cities in the world are situated in India. The rising industrial work, construction activities, type of material used for construction, and other factors have reduced thermal cooling and created temperature imbalance, thereby creating a vicious effect called “urban heat island” (UHI) or “surface urban heat island” (SUHI). Several researchers have also related it with climate change due to their contribution to the greenhouse effect and global warming. In this study, we have particularly emphasized northern India, including Punjab, Rajasthan, Haryana, and Delhi. We created a Google Earth Engine (GEE) based Web-App to assess the UHI intensity over the past 15 years (2003–2018). We are using Moderate Resolution Imaging Spectroradiometer (MODIS) images, Landsat 5, 7, and 8 data for studying UHI. The land surface temperature (LST) based UHI intensity (day and night time) will be available for major metropolitan cities with their respective clusters. With feasibility in SUHI monitoring, we can address an increasing need for resilient, sustainable, and safe urban planning of our cities as portrayed under the Sustainable Development Goals (SDG 11 highlighted by United Nations).


Author(s):  
Safdar Ali Shirazi ◽  
Khadija Shakrullah ◽  
Saadia Sultan Wahla ◽  
Mareena Khurshid

The aim of present study is to evaluate and assess the impact of built-up areas on development of the urbanheat island (UHI).The study mainly focused on Lahore, which is one of the mega cities of Pakistan. In terms ofpopulation size, Lahore is the second largest city of Pakistan with 11.13 million inhabitants. The geospatial techniques(Remote Sensing and Geographical Information System) along with statistical applications were applied to find out theLand Cover Land Uses changes and consequent development of builtup areas over the period of 2000 and 2015. Tostudy the UHI, the meteorological data of each 30 minutes for 36 days starting from 30th June 2015 to 4th August 2015were collected through direct on site observation by using digital weather station. The results of UHI were crosschecked by obtaining land surface temperature by using thermal infrared (TIR) band 6 of the Landsat-7 TM. The resultsshow that the LCLU and built environment have direct impact on development of UHI. The areas where there wasmore vegetation cover had less temperature while in urban areas, the temperature was measured higher. Over the periodof 36 days, the average UHI remained 5.5°C and the highest intensity of UHI was observed as 8.3°C thus augmentedresearch rationale. The study suggests establishment of a thick network of automatic weather stations in Lahore togauge the urban heat island intensity and to plant indigenous trees on vacant swaths and develop urban forest tomitigate city’s rising temperature.


Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhi Qiao ◽  
Xiping Han ◽  
Chen Wu ◽  
Luo Liu ◽  
Xinliang Xu ◽  
...  

In the process of rapid urbanization, urban heat island (UHI) effect has been showing more and more significant impacts on human well-being. Therefore, a more detailed understanding of the impact of three-dimensional (3D) building morphology on UHI effect across a continuum of spatial scales will be necessary to guide and improve the human settlement.This study selected 31 provincial capital cities of mainland China to analyze the impacts of the 3D building morphology, including the number, area, height, volume, and the surface area of the buildings, on the land surface temperature (LST). By exploring how the influence of 3D building morphology on LST changes with the increase of spatial scale (between 0 and 600 m radii), this study finally recognized which 3D building morphology index is the most significant index affecting LST in different cities, and which spatial scale these 3D building morphology indexes have the most significant impact on LST. The results showed that the building area is the most important 3D building morphology parameter affecting the LST, while the building height has the slightest influence on the LST. These effects are more significant in the spatial scale of 150 m–540 m, and the spatial scale increases with the increase of building areas in developed cities. These results highlight the necessity of considering fine-grained management in the governance and alleviating of the urban thermal environment through urban planning and urban renewal strategies.


2020 ◽  
Vol 10 (4) ◽  
pp. 64-68
Author(s):  
Safdar Ali Shirazi ◽  
Khadija Shakrullah ◽  
Saadia Sultan Wahla ◽  
Mareena Khurshid

The aim of present study is to evaluate and assess the impact of built-up areas on development of the urbanheat island (UHI).The study mainly focused on Lahore, which is one of the mega cities of Pakistan. In terms ofpopulation size, Lahore is the second largest city of Pakistan with 11.13 million inhabitants. The geospatial techniques(Remote Sensing and Geographical Information System) along with statistical applications were applied to find out theLand Cover Land Uses changes and consequent development of builtup areas over the period of 2000 and 2015. Tostudy the UHI, the meteorological data of each 30 minutes for 36 days starting from 30th June 2015 to 4th August 2015were collected through direct on site observation by using digital weather station. The results of UHI were crosschecked by obtaining land surface temperature by using thermal infrared (TIR) band 6 of the Landsat-7 TM. The resultsshow that the LCLU and built environment have direct impact on development of UHI. The areas where there wasmore vegetation cover had less temperature while in urban areas, the temperature was measured higher. Over the periodof 36 days, the average UHI remained 5.5°C and the highest intensity of UHI was observed as 8.3°C thus augmentedresearch rationale. The study suggests establishment of a thick network of automatic weather stations in Lahore togauge the urban heat island intensity and to plant indigenous trees on vacant swaths and develop urban forest tomitigate city’s rising temperature.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Afrilyani Kontryana ◽  
Abdul Wahid Hasyim ◽  
Amin Setyo Leksono

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.


Author(s):  
Jefferson Inayan de Oliveira Souto ◽  
Julia Clarinda Paiva Cohen

Abstract Cities experience the extensive urban heat island effect (UHI), which continue to pose challenges for humanity's increasingly urban population, where tropical cities have experienced a continued and rapid urbanization process in the past few decades. We present the evolution of surface UHI and its controlling factors in the Metropolitan Region of Belém, over the last 16 years (2003-2018), which has experienced unique consolidated economic growth and urban transformation under wet equatorial climate. We incorporate MODIS and Landsat satellite data and evaluate statistical techniques for estimates the variation in the land surface temperature (LST) during two seasons: wet season and dry season. Our result revealed that the regions of fast urbanization resulted in a decrease of normalized difference vegetation index and increase of LST. In addition, annual maps showed the spatial pattern of surface UHI intensities were produced based on daytime and nighttime temperature, and the analysis result indicated that the spatial distribution of high heat capacity was closely related with the densely built-up areas. These findings are helpful for understanding the urbanization process as well as urban ecology, which both have significant implications for urban planning and minimize the potential environmental impacts of urbanization in Metropolitan Region of Belém.


Sign in / Sign up

Export Citation Format

Share Document