Single-Particle Chemical Composition in the Arctic during the Winter-Spring Transition

Abstract:

Atmospheric particles have significant, but highly uncertain, impacts on the Arctic climate by decreasing snow/ice albedo, scattering/absorbing solar radiation, nucleating cloud droplets and ice crystals, and contributing to atmospheric trace gas budgets. In the winter, atmospheric particles and trace gases are transported from the mid-latitudes to the Arctic, forming a springtime ‘Arctic haze’. In the winter-spring, thinning sea ice is causing ice fracturing and the formation of open sea ice leads, which are suggested to be a source of local sea spray aerosol. To investigate the chemical composition and source of atmospheric aerosols during the winter-spring transition in the Arctic, 0.1-5 µm particles were collected during January and February 2014 near Barrow, Alaska. The elemental composition and morphology of these particles were examined using computer-controlled scanning electron microscopy with energy dispersive X-ray spectroscopy (CCSEM-EDX). Significantly, major contributions of sea spray aerosol were observed for both submicron and supermicron size ranges during a nearby open lead event, and organic-sulfate (‘Arctic haze’) particles were also abundant at <1 µm in diameter. The single-particle chemical composition, sources, and evidence of aging processes will be discussed.