Effect of Arctic sea ice on aerosols in Eastern Lapland, Finland

Theme 1. Environmental protection
Session Name 1.4 Sustainable development of the Arctic - boreal regions
Presentation Type Oral
Presenter
Author(s) Ella-Maria Duplissy (University of Helsinki, Finland), Simo Hakala (University of Helsinki, Finland), Victoria Sinclair (University of Helsinki, Finland), Riikka Väänänen (University of Helsinki, Finland), Veli-Matti Kerminen (University of Helsinki, Finland)
Abstract text

Changes in sea ice are likely to affect the aerosols in the continental Arctic. We calculated linear regressions to median aerosol concentrations and mode peak diameters at SMEAR I in eastern Lapland, Finland, as a function of time over sea ice (TOSI), time over open sea (TOOS) and time over land (TOL). We divided the data into summer (Jun-Sep) and winter (Oct-May) as well as NAO and AO positive and negative phases.


During summer, the total aerosol number, Aitken mode and accumulation mode


concentrations were decreasing with the time the air mass spent over the sea ice by -8.9, -5.3 and -1.6 cm-3h-1, respectively. Aitken and accumulation mode diameters were decreasing -0.3 nm/h and -0.5 nm/h, respectively. Accumulation mode concentration and diameter increased by 0.8 cm-3h-1 and 0.3 nm/h, respectively, as a function of TOOS. Total, nucleation mode and Aitken mode concentrations decreased in winter as a function of TOSI (-1.3, -0.3, -0.6 cm3/h, respectively). Accumulation mode concentration and diameter were decreasing by -0.4 cm-3h-1 and -0.2 nm/h as a function of TOOS.


We conclude, that Arctic sea ice has a strong impact on the aerosol concentrations in eastern Lapland, and the changes in the sea ice extent and time that the air parcel spends over sea ice can have an influence on the aerosol-cloud interactions in the continental Arctic. The concentrations of potential CCN have contrasting trends with decreasing sea ice during summer and winter.

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