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Interannual variability of air-sea exchange of mercury in the global ocean: the “seesaw effect” in the equatorial Pacific and contributions to the atmosphere
  • shaojian huang,
  • Yanxu Zhang
shaojian huang
Nanjing University
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Yanxu Zhang
Nanjing University

Corresponding Author:zhangyx@nju.edu.cn

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Air-sea exchange of mercury (Hg) is influenced by meteorological factors that have substantial interannual variability. Here we investigate its interannual variability and influcing factors by using the MITgcm ocean model. We elucidate a latitudinal pattern with a relatively small variability in the mid-latitudes (6.4%-8.5%) and a large one in the Arctic and Equator (15%). Wind speed, salinity, and sea ice dominate the patterns in equatorial, mid-, and high-latitudinal oceans, respectively. A in equatorial Pacific is found between El Niño and La Niña events, owing to wind speed anomaly caused by the variation of Walker circulation. A higher atmospheric Hg concentration (1-2%) in northern hemisphere is found by the GEOS-Chem simulation due to higher ocean evasion fluxes, consistent with the CAMNet and EMEP (1-11%) observations. Besides, a slight fluctuation in the upper tropospheric (±0.5%) reveals a potential contribution from the ocean evasion for interannual variability of tropospheric Hg.
18 May 2021Published in Environmental Science & Technology volume 55 issue 10 on pages 7145-7156. 10.1021/acs.est.1c00691