6 research outputs found

    Seasonal Aerosol Classification Over South Asia by Satellite based Atmospheric Optical Data

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    Aerosol optical characteristics have been investigated to explore regional and seasonal inconsistencies of aerosols and to define the dominant type throughout South Asia from 2001 to 2021. MODIS aerosol products from collection 6.1 have been used in present study, that comprise daily values of Angstrom exponent (AE) and aerosol optical depth (AOD) data. MODIS-derived AODs are validated by using nine ground-based AERONET station data. Overall, an adequate correlation is found among the two datasets. However, an overestimation of the MODIS retrievals is found in one site named Jaipur and underestimations are found at two sites named as Gandhi-college and Karachi. The seasonal evaluation shows that aerosol distribution found between 0 and 1.05, depending on the change in geographical location. The highest AOD value originates over the Indo-Gangetic plain (IGP), mostly throughout warm season. The second maximum AOD value covers a large area of South Asia during spring, summer and autumn. The lowest values of AOD are found in winter season excluding the IGP. A region with high aerosol optical depth (AOD) values support a low value of angstrom exponent (AE) indicating the coarse aerosol during warm seasons (spring and summer) over IGP. The region with high AOD and high AE values is showing fine aerosol during the mild to cold seasons (autumn and winter). The threshold values for AOD and AE have been used to classify aerosols. The results demonstrate that urban/industrial aerosols prominent in every season across the region dominate in spring and summer due to frequent occurrence of dust events. The mixed type aerosol is second largest contributor in aerosol formation in all seasons. The Biomass burning/smoke aerosol is dominant over IGP due to open forest and crop burning in autumn. Clean and maritime aerosol has small unnoticeable involvement in the studied region

    Impact of Urbanization Growth on Land Surface Temperature using remote sensing and GIS: A Case Study of Gujranwala City, Punjab, Pakistan

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    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 ËšC 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

    Analytical Review of Land Use Changes by Remote Sensing and GIS Techniques in District Gujrat, Pakistan

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    Assessment of changes in land use and land cover through remote sensing and GIS is very important and keyanalysis. Urbanization has been continued by the rapid growth in the world economy so; it is the key study withregards to agriculture and urbanization. The aim of this study is to determine the loss of agriculture land and effects ofincreasing urbanization on surface temperature. For urban temperature impact analysis, distinctive time series ofLandsat images have been chosen. Temporal analysis for different time series shows the decrease in agriculture landand increase in built up area. Urbanization increased the temperature up to 20C. Positive correlation is found betweenbuilt-up area and temperature and negative correlation is found between green spaces and temperature. Unplannedurban sprawl and lack of proper irrigation system according to population are major problems in study area. Recentstudy will be helpful for decision makers to develop the sustainable environment policy in future

    Spatial Distribution of Noise Released from Iron and Steel Industry and their Effects on Human Health in the Lahore City, Pakistan

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    This research investigates the phenomenon of perception of people about industrial noise pollution and its effects on human health. Thirty-six (36) industries were selected for estimation of noise levels and its effects on human health. Concurrently, samples of one hundred and fifty (150) respondents were also taken from nearby residential area, using random sampling method. The key tool of data collection was well-structured questionnaires consisting of twenty-one questions. Chi-Square test was used for examination of data, which illustrated effects of industrial noise on people living in industrial zone. The noise level results indicated that the mean values were exceeding permissible environmental standard used in Pakistan. Majority of respondents (50.6 %) were conscious about the basic reason of noise pollution in study area. Eighty-two percent (82%) people have opinion that old technology was the basic cause for noise pollution. It was shocking to see the results which indicate that 99.8% people are suffering from noise related diseases. This include 81.3% with increase anger, 81.5% with ear ache, 16% with ear discharge, 79.3% with high blood pressure, 78% with depression, 77.3% temporary hearing loss, 9.3% permanent hearing loss. Only 23.3% of people conduct regular hearing test
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