Publications by authors named "Pradeep Khatri"

Long-term aerosol optical depth (AOD) datasets focused on the Pacific Ocean in the downwind area of China over a 19-year period from 2003 to 2021 were derived from satellite observations, reanalysis datasets, and numerical simulations. Considering the significant year-to-year changes in the amounts of aerosols transported from China to the Pacific Ocean during this period, we proposed a metric named R. This is defined as the AOD over the ocean relative to that near the eastern coast of China within the same latitude band (25-30°N).

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Exposure to particulate matter less than 2.5 µm in diameter (PM) is a cause of concern in cities and major emission regions of northern India. An intensive field campaign involving the states of Punjab, Haryana and Delhi national capital region (NCR) was conducted in 2022 using 29 Compact and Useful PM Instrument with Gas sensors (CUPI-Gs).

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Article Synopsis
  • Aerosols influence cloud properties and the hydrological cycle by modifying cloud droplet sizes, leading to a phenomenon known as the Twomey-effect, where increased aerosols usually reduce droplet sizes.
  • However, in regions with high aerosol concentrations, these aerosols can also enhance cloud droplet sizes depending on the liquid water path, showing both negative and positive effects on droplet size.
  • The study emphasizes that in thicker clouds, aerosols can promote droplet coalescence, while in thinner clouds, they may decrease droplet size, indicating complex interactions between aerosols and cloud formation in polluted areas.
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Biomass burning emits a large quantity of gaseous pollutants and aerosols into the atmosphere, which perturbs the regional and global climate and has significant impacts on air quality and human health. In order to understand the temporal and spatial distributions of biomass burning and its contribution to aerosol optical and radiative impacts, we examined fire emission data and its contribution to aerosol optical and radiative impacts over six major hot-spot continents/sub-continents across the globe, namely North-Central (NC) Africa, South America, US-Hawaii, South Asia, South East Asia, and Australia-New Zealand, using long-term satellites, ground-based and re-analysis data during 2000-2021. The selected six sites contributed ∼70% of total global fire data.

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COVID-19 related restrictions lowered particulate matter and trace gas concentrations across cities around the world, providing a natural opportunity to study effects of anthropogenic activities on emissions of air pollutants. In this paper, the impact of sudden suspension of human activities on air pollution was analyzed by studying the change in satellite retrieved NO concentrations and top-down NOx emission over the urban and rural areas around Delhi. NO was chosen for being the most indicative of emission intensity due to its short lifetime of the order of a few hours in the planetary boundary layer.

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