111 - Year-round Atmospheric Mercury Measurements Over the Central Arctic Ocean During the MOSAiC Expedition

Building on a synthesis of literature published since 2011, the Arctic Monitoring and Assessment Programme (AMAP) mercury (Hg) update Report gives an overview of our current understanding of the present-day Hg exchange fluxes and mass budget in the Arctic. Model-based estimates were obtained using an ensemble of four chemical transport models. These cutting-edge models were evaluated against available atmospheric measurements at circumarctic ground-based sites and against ambient air Hg concentrations collected over the western Arctic Ocean during the August-October 2015 US Arctic GEOTRACES cruise. However, the AMAP report highlights that a more thorough evaluation of models’ performances is hampered by the absence of year-round measurements over the Arctic Ocean. This study fills this gap by providing the first year-round record of gaseous elemental Hg concentrations over the central Arctic Ocean during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition (https://mosaic-expedition.org) from October 2019 to September 2020. In this poster we discuss seasonal variations and potential sources of Hg in the high Arctic. We also evaluate the performances of the above-mentioned model ensemble against this new set of atmospheric observations over the central Arctic Ocean.

Hélène Angot, Dean Howard, Stephen Archer, Ludovic Bariteau, Jesper Christensen, Ashu Dastoor, Detlev Helmig, Jacques Hueber, Hans-Werner Jacobi, Kevin Posman, Andrei Ryjkov, Oleg Travnikov, Byron Blomquist