Transport Regimes During the MOSAiC Campaign: a Lagrangian Analysis of Continental Sources and Sea Surface Interactions.

The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) campaign involved a one-year-long ship expedition into the Central Arctic (September 2019 - October 2020) with a comprehensive set of atmospheric measurements aiming to improve the understanding of the coupled climate processes in the region. To support the interpretation of trace gases and aerosol as well as meteorological measurements, backward transport calculations were performed along the ship track with the Lagrangian particle dispersion model FLEXPART (Stohl et al., 2005; Pisso et al., 2019). The simulations were driven with hourly ERA5 data at 0.5 horizontal resolution. Every 3 hours, 100000 particles were initialized at Polarsterns location and traced backward for 30 days. The simulations, coupled with emissions fluxes, give a description of the transport conditions of a specific species from its source to the point of measurements. We present here the results of the transport analysis for various trace gases and aerosols and a description of the main transport patterns during the whole MOSAiC campaign period. With a similar approach, the analysis has been coupled to daily-resolved satellite data of sea ice cover, providing an estimate of the sea ice influence and its seasonal variability as well as influence from the open ocean and continental land surface. References: Pisso, I., E. Sollum, H. Grythe, N. I. Kristiansen, M. Cassiani, S. Eckhardt, D. Arnold, D. Morton, R. L. Thompson, C. D. Groot Zwaaftink, N. Evangeliou, H. Sodemann, L. Haimberger, S. Henne, D. Brunner, J. F. Burkhart, A. Fouilloux, J. Brioude, A. Philipp, P. Seibert, and A. Stohl (2019): The Lagrangian particle dispersion model FLEXPART version 10.4. Geosci. Mod. Dev. 12, 4955-4997, doi:10.5194/gmd-12-4955-2019. Stohl, A., C. Forster, A. Frank, P. Seibert, and G. Wotawa (2005): Technical Note : The Lagrangian particle dispersion model FLEXPART version 6.2. Atmos. Chem. Phys. 5, 2461-2474.