Manu Mehta

Indian Space Research Organization | ISRO · Indian Institute of Remote Sensing (IIRS)

This study has made an effort to understand the long-term changes of aerosol loadings as well as temperature in the post-monsoon season (October–November) over a long period of 40 years (1980–2019) for the Indian region using MERRA-2 reanalysis data. Special emphasis has been given on the highly populated and polluted cities of the country notably,...

Previous attempts at aerosol optical depth (AOD) retrieval from top-of-atmosphere satellite signals using a simplified approach have been limited in their assessment over selective surface types, calibration sites and given the low surface reflectance components at lower wavelengths, have mostly relied, fully or partially, on near-UV or blue spectr...

COVID-19 had such a devastating effect on humanity that several governments worldwide were forced to establish regional and national level Lockdowns in an attempt to reduce the severity of the infection. The nationwide lockdown had been implemented on 24 March 2020 in India with the inevitable restrictions. Along with the effect on the population o...

This study has made an effort to understand the long-term changes of aerosol loadings as well as temperature in the post-monsoon season (October-November) over a 40-year long period (1980–2019) for the Indian region using MERRA-2 reanalysis data. Special emphasis has been given on the highly populated and polluted cities of Delhi, Mumbai, Kanpur, a...

The present study employs Google Earth Engine (GEE), a new cloud computing platform, to monitor changes in LULC, focusing on the shifting forest cover in the East Godavari district of Andhra Pradesh through loss and gain scenarios. Satellite data collected in 2001, 2016, and 2022 at a spatial resolution of 30 m from Landsat 7 ETM+, Landsat 8 OLI/TI...

Knowledge of aerosol distribution and trends in the total atmospheric column as well as at different vertical levels of the atmosphere can provide crucial inputs to understand the role of aerosols in the changing climatic scenario. Indian region is one of the major aerosol hotspots and it is therefore important to have a continuous monitoring of va...

The spatial and temporal variation of satellite derived pre-monsoonal Aerosol Optical Depth (AOD) over the Indian region has been studied using long-term (2005–2021) satellite data from Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI). In particular, three zones were selected, based on the dominance of nat...

The decoupling of aerosol signals from the at-sensor reflectance measured through a space-borne sensor is a complex task due to the involved coupling mechanism of the interaction of light with the Earth's surface and the atmosphere. Specifically, the retrieval becomes more challenging over the land surface due to appreciable reflectance from the ta...

On 21 June 2020, an annular solar ec-lipse phenomenon took place. The path of the ‘ring of fire’ spanned across Afri-ca and Asia (Figure 1a). In addition to the traditional methods of observing the solar eclipse through telescopes using so-lar filters or using solar projectors, this phenomenon can also be captured using satellite data. The shadow c...

Since the past two decades, high aerosol loading is being observed over the Indian mainland. It becomes necessary to continuously monitor and understand the distribution of aerosol loading over the Indian landmass, as it might have serious health and climatic implications. Whereas there have been extensive studies reporting seasonal distribution an...

Aerosol loadings over the Indian region has been increasing since several years increasing levels of the particulate matter may increase the health risks and also can influence the Earth’s radiation budget Further, the impacts may also be observed over cloud properties The information from low earth orbit satellites could provide spatially continuo...

This study presents the aerosol vertical profiles for the last 10 years 2008-2018 over Vishakhapatnam and surrounding region within a circle of 50 km. For this purpose, we have used daily Level 2 version 4 aerosol products from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO) sensor onboard Cloud-Aerosol Lidar and Infrared Pathfinder Sate...

Snow and glaciers in the NorthEastern Himalayas are primary water resources for various rivers originating in the eastern side of the Himalayan range. Global warming and changes in the climate system are believed to play a pivotal role in the changes of snow cover over the NorthEastern Himalayas. The analysis of data from remote sensing sensors can...

Aerosols play a vital role in influencing the climate both by cooling and warming up the Earth’s surface and also by altering the cloud properties. Due to natural and large amount of anthropogenic factors, Indian region observes high variability of loadings in aerosols both in terms of space and time in the planetary boundary layer. Dust storms in...

The correlations between absorbing aerosol index (AAI), precipitation and Normalised Differential Vegetation Index (NDVI) have been shown in this study for the Indian region annually and seasonally (winter, pre-monsoon, monsoon and post-monsoon) from 2000 to 2013. Daily Aerosol Index has been obtained from OMAERov003 product provided by OMI-Aura se...

Asia, being the largest continent, both in its size and population is affected by different types of atmospheric aerosols. Also, owing to different local emissions/sources along with the long range transport mechanisms, there is a large variability in the distribution of different types of aerosols across the continent. Not only the effects are per...

Studies have shown that aerosol loading particularly due to the absorbing particles over Himalayan region might impact the snow properties and cover. Hence, a comprehensive study on the aerosol distribution over this large mountain ecosystem, particularly focussing on the absorbing particles requires utmost attention. The purpose of this study is t...

Dust particles of different size and origins, form major part of air pollution in the atmosphere. The qualitative and quantitative estimates of dust from ground-based measurements provide accurate information at regional scales. However, data from space-borne instruments provide continuous spatial information at a variety of different spatial scale...

National Symposium on Understanding Weather and Climate Variability: Research for Society

On 18 th June, 2017 an ample amount of smoke plume had been dispersed into the atmosphere during the raging forest fire event which had taken place in Central Portugal, thereby affecting the air quality of the surrounding regions. The detection of smoke aerosols has been carried out by using the aerosol data from MODIS and OMI. The transport of air...

On 18th June 2017, an ample amount of smoke plume had been dispersed into the atmosphere during the raging forest fire event which had taken place in Central Portugal, thereby affecting the air quality, vegetation, socioeconomic life of the surrounding regions. This study deals with the vertical profile of aerosols during the forest fire. The verti...

In 2016 a large amount of smoke was dispersed into the atmosphere from forest fires in the state of Uttarakhand thereby affecting the air quality in the surrounding regions. The detection of smoke aerosols has been carried out by using data from Moderate Resolution Imaging Spectrometer (MODIS) & Ozone Monitoring Instrument (OMI). The smoke transpor...

Every year a large amount of smoke is released into the air from forest fire incidents across the Indian state of Uttarakhand thereby affecting the air quality in and around the area. Detection of smoke aerosols along the vertical air column has been carried out by using data from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (C...

Single Scattering Albedo (SSA) is one of the most important parameters in deciding the type of aerosols present in the atmosphere. This study mainly aims to study the characteristics of SSA at 388nm wavelength (UV region) at global scale using Ozone Monitoring Instrument (OMI) (level-3) data which is on board the NASA Aura. The study is carried out...

Based on their interaction with solar radiations, aerosols may be categorized as absorbing or scattering in nature. The absorbing aerosols are coarser and influence precipitation mainly due to microphysical effect (participating in the formation of Cloud Condensation Nuclei) and radiative forcing (by absorbing electromagnetic radiations). The promi...

Aerosol distribution at global and regional scales is one of the crucial parameters for climate change assessment. The study presents global spatio-temporal variations in aerosol optical depth (AOD) retrieved by Moderate Resolution Imaging Spectroradiometer (MODIS) and Multiangle Imaging Spectroradiometer (MISR) sensors at spatial resolutions of 1°...

Natural vegetation cover and crop yield vary spatially and temporally in a diverse manner. Understanding this variation requires a robust analysis of important climatic factors such as rainfall, temperature, sunshine hours etc., along with LULC dynamics. In this study, NDVI has been used as an indicator of vegetative greenness and productivity. Bas...

Natural vegetation cover and crop yield vary spatially and temporally in a diverse manner. In this study, NDVI has been used as an indicator of vegetative greenness and productivity. Understanding this variation requires a robust analysis of important climatic factors such as rainfall, temperature, sunshine hours etc., along with LULC dynamics. Bas...

Natural vegetation cover and crop yield vary spatially and temporally in a diverse manner. Understanding this variation requires a robust analysis of important climatic factors such as rainfall, temperature, sunshine hours etc., along with LULC dynamics. In this study, NDVI has been used as an indicator of vegetative greenness and productivity. Bas...

This study considers the seasonal and annual analysis of aerosol optical depth (AOD) in three most populated countries of Asia namely: China, India and Indonesia. These countries are having increasing rates of population, industrialization, transportation etc., due to which aerosol loading in these nations is becoming a subject of great concern. Th...

Aerosols affect the earth's climate system both on a regional as well as on a global scale. Several studies have identified India (the second most populous country) as one of the regional hot spots of aerosols due its increasing anthropogenic activities. The paper presents a temporal (annual and seasonal) study of aerosol optical depth (AOD) in the...

Atmospheric aerosols affect the earth’s climate system both directly and indirectly. Once aerosols are produced, they can get transported from areas of high emissions to clean remote and marine environments under favourable meteorological conditions. The study of vertical distribution of aerosols in the troposphere is important for determining thei...

Aerosol optical depth retrieval over land surface using remote sensing employs the use of radiative transfer simulations and/or simultaneous measurements of atmospheric parameters at the time of satellite pass. Also, an accurate estimate of land surface parameters is also required in order to separate the atmospheric component from the land surface...

The retrieval of aerosols using remote sensing requires an accurate estimation of both atmospheric and land surface parameters. Radiative transfer codes along with simultaneous field measurements are used to solve the forward and the inverse problems. This study uses the simple model for atmospheric radiative transfer to simulate the aerosol optica...

Land degradation is one of the major ecological problems faced by the world today. Remote sensing, now-a-days plays an important role to map degraded lands with regard to their extension, type, and severity. Traditional classification methods are mostly based on the properties of spectral reflectance. Thus, classification of features having similar...

An attempt was made to retrieve vegetation albedo in Red and SWIR bands (AWiFS data) and results were compared with Moderate Resolution Imaging Spectroradiometer (MODIS) albedo product. Relative error of 0.4 in red and 0.18 in red bands was observed.