The Marginal Ice Zone as a dominant source region of atmospheric mercury during central Arctic summertime

• Published in: Nature Communications
• Main Authors: Yue, Fange, Angot, Hélène, Blomquist, Byron, Schmale, Julia, Hoppe, Clara, J M, Lei, Ruibo, Shupe, Matthew, D, Zhan, Liyang, Ren, Jian, Liu, Hailong, Beck, Ivo, Howard, Dean, Jokinen, Tuija, Laurila, Tiia, Quéléver, Lauriane, L J, Boyer, Matthew, Petäjä, Tuukka, Archer, Stephen, D, Bariteau, Ludovic, Helmig, Detlev, Hueber, Jacques, Jacobi, Hans-Werner, Posman, Kevin, Xie, Zhouqing
• Other Authors: Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Ecole Polytechnique Fédérale de Lausanne (EPFL), University of Colorado Boulder
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Arctic; Ozone; Mercury; Bromine; Cryosphere; Atmosphere; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Arctic Ocean; Gam
• Online Access: https://hal.science/hal-04292742; https://hal.science/hal-04292742/document; https://hal.science/hal-04292742/file/Yueetal_NatureComm2023.pdf; https://doi.org/10.1038/s41467-023-40660-9

International audience Atmospheric gaseous elemental mercury (GEM) concentrations in the Arctic exhibit a clear summertime maximum, while the origin of this peak is still a matter of debate in the community. Based on summertime observations during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition and a modeling approach, we further investigate the sources of atmospheric Hg in the central Arctic. Simulations with a generalized additive model (GAM) show that long-range transport of anthropogenic and terrestrial Hg from lower latitudes is a minor contribution (~2%), and more than 50% of the explained GEM variability is caused by oceanic evasion. A potential source contribution function (PSCF) analysis further shows that oceanic evasion is not significant throughout the ice-covered central Arctic Ocean but mainly occurs in the Marginal Ice Zone (MIZ) due to the specific environmental conditions in that region. Our results suggest that this regional process could be the leading contributor to the observed summertime GEM maximum. In the context of rapid Arctic warming and the observed increase in width of the MIZ, oceanic Hg evasion may become more significant and strengthen the role of the central Arctic Ocean as a summertime source of atmospheric Hg.