Browsing by Author "Harshbardhan Kumar"

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Airborne heavy metals deposition and contamination to water resources
(Elsevier, 2022) Harshbardhan Kumar; Gurudatta Singh; Virendra Kumar Mishra; Ravindra Pratap Singh; Pardeep Singh
Heavy metals are group of metals or metalloids with higher atomic weight, density, and toxicity. These metals occur in a natural background geochemical composition in Earth’s crust, atmosphere and water. But in the past few decades, due to increased anthropogenic activities and emissions, the background level of heavy metals has changed considerably, which has overwhelmed the natural biogeochemical cycling processes of the metals across the Earth’s system. Most of the metals exist in ionic or inorganic form which cannot be further disintegrated like organics and thus persist, accumulate, and get transported from one sphere to another in the interlinked environmental system. They are highly undesirable and of paramount concern because of their toxicity, even at a low concentration, except for some essential metals. Mining, smelting, and refining of metals, industrial processes (electroplating, coating, galvanizing, paint, and spray), coal-based power plant, agriculture activities, and open metallurgical processes are some potential anthropogenic sources of heavy metal emission to atmosphere. Once the metals or metalloids bound particle or vapor emitted to the surrounding atmosphere their fate come under the purview of prevailing meteorology and wind circulation. Their natures of nondegradability add another moment to persist longer in the atmosphere and thus get long-range transported far away from the source region. That eventually scavenged through wet or dry depositional processes over open lands, water bodies and on plant leaves. In aquatic system via physiochemical and biological processes, they get metabolized into ingestible form which may then be taken up by plants and lower living organisms. This chapter will present an overview of in-land emission sources of heavy metals, their advection in the free troposphere and eventually their deposition to aquatic body. © 2023 Elsevier Inc. All rights reserved.
Characterizing aerosols during forest fires over Uttarakhand region in India using multi-satellite remote sensing data
(Elsevier Ltd, 2022) Sunita Verma; Manish Soni; Harshbardhan Kumar; Swagata Payra; Manoj K Mishra; Rohini Bhawar
Confirmed rise in average surface temperature and consequent prolonged dry days in tropical Himalayan foothills (tarai region) favors frequent wildfire event which make susceptible to the local forest vegetation and ecology. Recent improvement in spatio-temporal resolution of space-borne sensors provides an opportunity to routinely map these wildfires and estimate the consequence. Utilizing both active and passive space-borne multi-sensors, this study presents the active fire counts, columnar and vertical distribution of aerosol during 2013–2018 over Uttarakhand region of India. Our analysis shows maxima in active fire counts during April to late June months while minima in monsoon over the region. Particularly owing to the high temperature, low moisture, drying up of natural spring and availability of fuel materials in summer and scare precipitation in winter. Some limited spatio-temporal scale fire episodes are also marked in winter. The AOD values with maximum of 3.2 (0.5 mean) observed during the April 2016, while for the successive next two months, AOD of 2.0 and 1.2 are found over the fire burning regions. The Normalized Burn Ratio Thermal (NBRT) index are also found to be much higher for April and May 2016 with respect to 2015 and 2017. The comparative analysis of NBRT shows a positive difference towards the western side of Uttarakhand. Vertical feature mask and aerosol subtype profile details about the polluted dust and elevated smoke aerosols from surface to 10 km range during the intense fire events smoke were elevated and trapped within 3 to 10 km. The results demonstrate the potential of earth's observing satellites for characterization of emissions and in air quality management. © 2022 COSPAR
Impact of climate change on water quality and its assessment
(Elsevier, 2022) Pramod Kumar Yadava; Harshbardhan Kumar; Anubhuti Singh; Vinod Kumar; Sunita Verma
Worldwide changes in climatic conditions are encouraged by increase in the concentration of Green House Gases (GHGs), are widely perceptible in terms of continuous changing patterns of superficial temperature, rainfall pattern, wind-flow patterns, radiations, and other life-threatening weather conditions. With a wider consent from the regional and global scientific communities, Intergovernmental Panel on Climate Change (IPCC) has indisputably summarized that kind of fact. Therefore, in this ongoing era of global climate-change, the assessment of probable impact on water and its quality, being the most prominent and reliable resource for human existence, become a significant task. Lots of assessment and review study have been reported on the possible impact of climate-change on water cycling and precipitation pattern. Recently, in-situ quality assessment, satellite observational assessment, and modeling simulation studies are in progress to assess the possible impact of climate change on the quality of available water. These studies mostly reported that the rising temperature and hence changing climatic conditions are capable of varying the ecological balance of water as well its qualitative contents either by its indirect impact or by direct impact by performing various biochemical alternations, as the rise in the water temperature and changes in extremes like flash-flood worsen various reasons of pollution caused in water bodies. In a natural water system, sediment load, nutrients availability, dissolved organic carbon, and essential zoo planktonic community are found to be in a delicate balance. Change in the flow pattern and thus augmentation in nutrients concentration, predictable variation in climatic phenomenon leads to periodic phytoplankton blossoms and alteration of the ecological tropical balance. The resultant dissolved oxygen (DO) level is varied constantly and algal-blooms may range to the perilous level to affect negatively. In addition, melting glaciers and consequent rising levels of the sea are expected to encompass the zones of salinization toward freshwater resources, which results in the reduction in available freshwater resources in the coastal areas. Additionally, variations in the qualitative value of water are predictable to affect nutriment accessibility, steadiness, access, and consumption. All these detrimental effects of changing climate hence water quality can adversely impact food security and hence enhancing the vulnerability of the agriculturalists and civilizations of our rural culture surviving in arid regions like Asian and African deltas (IPCC, Technical report on climate change and water, June 2008). © 2023 Elsevier Inc. All rights reserved.
Role of Lightning NOx in Ozone Formation: A Review
(Birkhauser, 2021) Sunita Verma; Pramod Kumar Yadava; D.M. Lal; R.K. Mall; Harshbardhan Kumar; Swagata Payra
This paper provides an overview on the spatiotemporal distribution and evolution mechanism of lightning. The predominant mechanism of ozone formation in the upper troposphere is lightning-induced precursors such as oxides of nitrogen (NOx), carbon monoxide (CO), and hydrocarbons (HC). Lightning-induced NOx (LNOx) is one of the major ordinary sources of NOx in the upper atmosphere, particularly in the tropical region, but it is still highly uncertain as to the exact quantity. Various ground measurements, satellite observations and modelling studies on the lightning and global NOx source rate have been extensively studied and compared to find the variability in estimated global lightning-induced NOx. Lightning can influence the climate via the production of nitrogen oxides (NO + NO2 = NOx) followed by the production of ozone, another efficient greenhouse gas. The global annual lightning NOx of 5 ± 3 Tg year−1 has been estimated by modelling studies with an ozone creation efficiency of 6.5 ± 4.7 times that of surface NOx sources. Understanding and quantifying the processes and production of lightning and LNOx is important for assessment of ozone concentrations and its associated impacts on the global climate. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
The major lightning regions and associated casualties over India
(Springer, 2020) Pramod Kumar Yadava; Manish Soni; Sunita Verma; Harshbardhan Kumar; Ajay Sharma; Swagata Payra
Lightning, a climate-related highly localized natural phenomenon, claims lives and damage properties. These losses could only be reduced by the identification of active seasons and regions of lightning. The present study identifies and correlates the lightning-prone regions with the number of casualties reported over India at the state/union territory level. The seasonal and monthly composite satellite data of Lightning Imaging Sensor for the duration of 16 years (1998–2013) have been analyzed in this study for the identification of the major lightning-prone seasons and regions over India. The casualties due to lightning have also been estimated using data from Accidental Deaths and Suicides in India, National Crime Record Bureau report of India. The spatial distribution analysis reveals that lightning occurs mostly in hilly regions over India throughout the year (26 flash/sq. km/yr) and, however, causes lesser casualties because of the sparse population over the hilly terrain. The seasonal analysis reveals the most lightning phenomena occur during the pre-monsoon period (40–45 flash/sq. km/yr) over the northeast region of India. During the winter period, the lightning dominates over the northern parts of India such as Jammu and Kashmir. The state-wise casualties’ study reveals that maximum casualties are reported in Madhya Pradesh (313 deaths), Maharashtra (281 deaths) and Orissa (255 deaths) on an average per annum. The favorable climatic conditions, such as availability of moisture content, unstable atmosphere and strong convection, cause severe cases of lightning over the regions of Orissa and Maharashtra. © 2020, Springer Nature B.V.