Aircraft-based measurements of High Arctic springtime aerosol show evidence for vertically varying sources, transport and composition

Autor(en)

Megan D. Willis, Heiko Bozem, Daniel Kunkel, Alex K. Y. Lee, Hannes Schulz, Julia Burkart, Amir A. Aliabadi, Andreas B. Herber, W. Richard Leaitch, Jonathan P D Abbatt

Abstrakt

The sources, chemical transformations and removal mechanisms of aerosol transported to the Arctic are key factors that control Arctic aerosol-climate interactions. Our understanding of sources and processes is limited by a lack of vertically resolved observations in remote Arctic regions. We present vertically resolved observations of trace gases and aerosol composition in High Arctic springtime, made largely north of 80 degrees N, during the NETCARE campaign. Trace gas gradients observed on these flights defined the polar dome as north of 66-68 degrees 30' N and below potential temperatures of 283.5-287.5 K. In the polar dome, we observe evidence for vertically varying source regions and chemical processing. These vertical changes in sources and chemistry lead to systematic variation in aerosol composition as a function of potential temperature. We show evidence for sources of aerosol with higher organic aerosol (OA), ammonium and refractory black carbon (rBC) content in the upper polar dome. Based on FLEXPART-ECMWF calculations, air masses sampled at all levels inside the polar dome (i.e., potential temperature < 280.5 K, altitude 10 days) in the Arctic, while air masses in the upper polar dome had entered the Arctic more recently. Variations in aerosol composition were closely related to transport history. In the lower polar dome, the measured sub-micron aerosol mass was dominated by sulfate (mean 74 %), with lower contributions from rBC (1 %), ammonium (4 %) and OA (20 %). At higher altitudes and higher potential temperatures, OA, ammonium and rBC contributed 42 %, 8 % and 2 % of aerosol mass, respectively. A qualitative indication for the presence of sea salt showed that sodium chloride contributed to sub-micron aerosol in the lower polar dome, but was not detectable in the upper polar dome. Our observations highlight the differences in Arctic aerosol chemistry observed at surface-based sites and the aerosol transported throughout the depth of the Arctic troposphere in spring.

Organisation(en)

Aerosolphysik und Umweltphysik

Externe Organisation(en)

National University of Singapore (NUS), University of Toronto, Johannes Gutenberg-Universität Mainz, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, University of Guelph, Environment and Climate Change Canada

Journal

Atmospheric Chemistry and Physics

Band

19

Seiten

57-76

Anzahl der Seiten

20

ISSN

1680-7316

DOI

https://doi.org/10.5194/acp-19-57-2019

Publikationsdatum

01-2019

Peer-reviewed

Ja

ÖFOS 2012

105204 Klimatologie, 105904 Umweltforschung, 103039 Aerosolphysik, 105206 Meteorologie

Schlagwörter

ASJC Scopus Sachgebiete

Atmospheric Science

Sustainable Development Goals

SDG 13 – Maßnahmen zum Klimaschutz

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/986e1622-a556-40f8-863e-437f7c6c24a3