Spatial and temporal variability of iodine in aerosol

Gómez Martín, Juan C., Saiz-Lopez, Alfonso, Cuevas, Carlos A., Fernandez, Rafael P., Gilfedder, Benjamin, Weller, Rolf, Baker, Alex R., Droste, Elise and Lai, Senchao (2021) Spatial and temporal variability of iodine in aerosol. Journal of Geophysical Research: Atmospheres, 126 (9). ISSN 2169-897X

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Abstract

In this work we describe the compilation and homogenization of an extensive dataset of aerosol iodine field observations in the period between 1963 and 2018 and we discuss its spatial and temporal dependences by comparison with CAM-Chem model simulations. A close to linear relationship between soluble and total iodine in aerosol is found (~80% aerosol iodine is soluble), which enables converting a large subset of measurements of soluble iodine into total iodine. The resulting data shows a distinct latitudinal dependence, with an enhancement towards the northern hemisphere (NH) tropics and lower values towards the poles. This behavior, which has been predicted by atmospheric models to depend on the global distribution of the main oceanic iodine source (which in turn depends on the reaction of ozone with aqueous iodide on the sea water-air interface, generating gas-phase I2 and HOI), is confirmed here by field observations for the first time. Longitudinally, there is some indication of a wave-one profile in the Tropics, which peaks in the Atlantic and shows a minimum in the Pacific. New data from Antarctica show that the south polar seasonal variation of iodine in aerosol mirrors that observed previously in the Arctic, with two equinoctial maxima and the dominant maximum occurring in spring. While no clear seasonal variability is observed in NH middle latitudes, there is an indication of different seasonal cycles in the NH tropical Atlantic and Pacific. Long-term trends cannot be unambiguously established as a result of inhomogeneous time and spatial coverage and analytical methods.

Item Type: Article
Faculty \ School: Faculty of Science > School of Environmental Sciences
Depositing User: LivePure Connector
Date Deposited: 23 Apr 2021 23:50
Last Modified: 10 May 2021 00:16
URI: https://ueaeprints.uea.ac.uk/id/eprint/79876
DOI: 10.1029/2020JD034410

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