Kuttippurath, J, Ardra, D, Raj, S et al. (1 more author) (2023) A seasonal OH minimum region over the Indian Ocean? Atmospheric Environment, 295. 119536. ISSN 1352-2310
Abstract
As the hydroxyl radical (OH) is the cleansing agent of the atmosphere, reduction in its concentration is a great concern for air quality and transport of trace gases across the latitudes and altitudes. In addition, OH determines the lifetime of most trace gases and non-CO2 greenhouse gases in the atmosphere. Since many pollutants have adverse health effects and are greenhouse gases, the changes in OH concentrations directly or indirectly affect public health and climate. Our analysis with OH data (from Tropospheric Emission Spectrometer and Copernicus Atmosphere Monitoring Service reanalyses) for the past 14 (2005–2018) years finds an OH minimum region over Indian Ocean, in the eastern Bay of Bengal at 6°–14° N and 92°–95° E. The Indian Ocean OH minimum reaches to 15 × 104 molec.cm−3 in April, and a secondary minimum of 18 × 104 molec.cm−3 in September–November. This seasonal minimum found around the Andaman and Nicobar Islands also hosts an active volcano, which releases noticeable amount of SO2 (OH sink) throughout the year. In addition, the biomass burning in spring and thus, the distribution of CO has a profound influence on the OH distribution in this region as Southeast Asia is one of the global hotspots of biomass burning, and the Indian Ocean OH minimum is located near that region. The El Niño and La Niño events also control the tropospheric ozone and CO distribution, and thus the interannual variability of OH minimum there. The WACCM model simulations reproduce the general latitudinal distribution and average seasonal cycle of OH, but not the extreme minimum OH values, although the simulations show the annual minimum in winter (December–January) in both ocean regions, which demands dedicated studies using chemical transport models. Therefore, this study reveals a seasonal OH minimum over Indian Ocean, which is very likely to influence the regional air quality and trace gas transport in the tropics.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022 Elsevier Ltd. All rights reserved. This is an author produced version of an article published in Atmospheric Environment. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Indian ocean, Stratosphere, Troposphere, Pollution, Western pacific ocean, OH |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > National Centre for Atmos Science (NCAS) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 21 Feb 2023 10:03 |
Last Modified: | 13 Dec 2023 01:13 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.atmosenv.2022.119536 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:196395 |
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