Urban Heat Islands and Vegetation Cover as a Controlling Factor

Journal of Geoscience and Environment Protection, 2018

Designing "liveable" cities as climate change effects are felt all over the world has become a priority to city authorities as ways are sought to reduce rising temperatures in urban areas. Urban Heat Island (UHI) effect occurs when there is a difference in temperature between rural and urban areas. In urban areas, impervious surfaces absorb heat during the day and release it at night, making urban areas warmer compared to rural areas which cool faster at night. This Urban Heat Island effect is particularly noticeable at night. Noticeable negative effects of Urban Heat Islands include health problems, air pollution, water shortages and higher energy requirements. The main objective of this research paper was to analyze the spatial and temporal relationship between Land Surface Temperature (LST) and Normalized Density Vegetation Index (NDVI) and Built-Up Density Index (BDI) in Upper-Hill, Nairobi Kenya. The changes in land cover would be represented by analyzing the two indices NDVI and BDI. Results showed the greatest increase in temperature within Upper-Hill of up to 3.96˚C between the years 2015 and 2017. There was also an increase in impervious surfaces as indicated by NDVI and BDI within Upper-Hill and its surroundings. The linear regression results showed a negative correlation between LST and NDVI and a positive correlation with BDI, which is a better predictor of Land Surface Temperature than NDVI. Data sets were analyzed from Landsat imagery for the periods 1987, 2002, 2015 and 2017 to determine changes in land surface temperatures over a 30 year period and it's relation to land cover changes using indices. Visual comparisons between Temperature differences between the years revealed that temperatures decreased around the urban areas. Minimum and maximum temperatures showed an increase of 1.6˚C and 3.65˚C respectively between 1987 and 2017. The comparisons between LST, NDVI and BDI show the results to be significantly different.

International Journal of Forestry Research

Banjarmasin City continues to develop rapidly. Malls and settlements are the newly built-up area that has reduced vegetation cover leading to changes in surface temperature in Banjarmasin City. Analysis of temperature changes is needed to determine the effect of increasing built-up areas and decreasing vegetation cover. The surface temperature can be detected and analyzed using satellite imagery. The study aimed to analyze the built-up area and vegetation density index and their effect on changes in surface temperature in Banjarmasin City from 2015 to 2019. We employed remote sensing and surveys to monitor and detect regional changes in urban areas due to rapid development. Built-up areas can be mapped using the Normalized Difference Built-Up Index (NDBI) algorithm, and vegetation density can be mapped using the Normalized Difference Vegetation Index (NDVI) algorithm. The correlation value between building density and surface temperature in 2015 was 0.826, and in 2019, it was 0.969....

Geodesy and Cartography, 2019

Journal of the Ghana Institution of Engineering (JGhIE)

The rapid urbanization coupled with tremendous growth in population and built-up areas in the cities has led to issues associated with global climate change impacts such as urban heat islands. This study is concerned with the spatial impact of the dynamics of urbanisation on urban heat island (UHI) in the Sunyani Municipality using Satellite Remote Sensing techniques. Sunyani municipal is a growing area in Ghana with increasing population and urbanisation. Many people in Ghana are moving to settle in Sunyani for different purposes. In this process, vegetated areas have been converted to urban areas and this has led to a reduction in the vegetation cover and increased the urban temperature in the municipality. Therefore, there is a need for a study on how the dynamics in the land use and land cover (LULC) in the municipal are contributing to urban heat. The main aim of this research is to identify the impact of LULC dynamics on UHI using multi-temporal Landsat images from 2001 to 202...

2012

Himalayan Journal of Applied Science and Engineering

Local Climate Zone (LCZ) classification has been intensively used in classification of urban and rural landscapes in the cities, which includes urban temperature studies. The urban heat island (UHI) in Kathmandu valley (Kathmandu, Bhaktapur, and Lalitpur), has been analyzed and standardized, which mainly focused on the Local Climate Zones (LCZs). The LCZs has distribute the landscape into homogeneous types on the basis of structural type, land surface cover, materials used, and into the anthropogenic activities. Such standardized classification has improved the meaning of urban research and made it easier to compare results among cities around the world. Landsat images, Google Earth, and SAGA-GIS software were used for creating LCZ map for Kathmandu for both March 2013 and March 2019 Landsat 8 TM/ETM+/OLI imagery was used to estimate land surface temperature (LST) For the estimation of LST world urban database and access portal tools (WUDAPT) algorithm was used considering emissivit...

International Journal of Economic and Environmental Geology, 2019

Globally, urban temperature is gradually increasing day by day. The prominent climatic condition called Urban Heat Island (UHI), is rising especially in the rapidly developed cities. Gujranwala a city of Punjab, Pakistan is experiencing fast urbanization which has led to ultimately increase in the observable UHI. The objective of recent study is to determine the effects of increasing urbanization on surface temperature and vegetation cover by different techniques of remote sensing and GIS. For this purpose, different time series of Landsat images were selected through which land surface temperature and NDVI (Normalized Difference Vegetation Index) has been calculated and urban heat island effect is analyzed. It is found that built-up areas have high temperature as compared to vegetative areas. Surface radiant temperature has increased up to 8 ˚C in Gujranwala due to urbanization. There is negative correlation between NDVI and LST. Economic activities in study area have decreased the vegetated parts leading to an increase in surface temperature and change in urban microclimate.

2020

This work is part of a national strategy for sustainable urban development to offer more rational information for urban planning and help regional planners in appropriate land use planning and sustainable development policies. This paper investigates the effects of urbanization on land surface temperature LST variation of Dakhla city (Morocco), using two sensors (Thematic Mapper (TM) and Operational Land Imager (OLI)). Images are also used to analyse the urban landscape and their impact on the thermal environment using the processing of Landsat satellite images over the 1984–2018 periods. The results show that the urban landscape grew by almost 85.79% which may be explained by the increase of urban population and economic development respectably. Urbanization and its Impact on Land Surface Temperature Changes Using Landsat Image in Dakhla City, Morocco http://www.iaeme.com/IJARET/index.asp 144 [email protected] Moreover, these results indicate that the higher land surface temperature...

FUTY Journal of the Environment, 2012

Temperature is an important component of the climate. The temperature of a developing city or state is constantly changing. The trend in temperature change in Nigeria is not consistent. Changes in temperature appear to be closely related to concentrations of atmospheric carbon dioxide. The degree of concentration depends on human interventions and the amount of sunlight reaching the earth's surface. Lagos State particularly in recent time has experienced decrease in vegetation and water pervious surfaces, which reduces surface temperature through evapotranspiration. This is as a result of rapid urbanization arising from inundating rural-urban migration. One of the implications is that anthropogenic heat is released to the environment due to energy consumption and increased impervious surface coverage thereby increasing the surface and atmospheric temperatures. LandSat Satellite imageries have been used to estimate Land Surface Temperature (LST) and urban thermal conditions. The mean LST result shows that, there is a significant increase in the temperature values from 1984 to 2002 (28.40 0 C-28.86 0 C). However, in 2006 the temperature decreases significantly to 28.37 0 C below 2002 temperatures in all LGAs. This variation could be attributed to the economic crisis/power outage in Nigeria which left manufacturing companies out of production/manufacturing between 2002 and 2006. Findings from this study reveals that there is a relationship between the surface temperature and the various Land Cover types. It shows a broad classification of the Land Cover types into Water bodies, Vegetation and Built-up areas respectively. With the spatial resolution and temporal coverage of two Landsat data of the environment, the derivation of the temperature information was achieved.

Journal of emerging technologies and innovative research, 2021

Rapid changes in land use/geography as a result of urbanization and industrialization have a negative impact on biodiversity, habitats, and local and regional environment. The formation of the Urban Heat Island (UHI) Effect is one of the most important consequences of urbanization. Unnao is the main urban area that connects the two metros through transportation corridors. Unnao experienced rapid urbanization as a result of industrial growth, and the LULC model's rapid evolution had a direct effect on LST. Important changes in LST have resulted from rapid changes in land use and land cover forms. The climate is impacted by urban growth. Using multi-temporal satellite data, the researchers wanted to see how land use/land cover (LULC) affected soil surface temperature in the Unnao area. Landsat 4-5TM and Landsat 8OLI were used to mine LST in 2005, 2011, and 2019. The findings will be analyzed from Unnao's land use transition to LST change over three years.