Overview paper: New insights into aerosol and climate in the Arctic

Jonathan P. D. Abbatt (1) , W. Richard Leaitch (2) , Amir A. Aliabadi (3) , Allan K. Bertram (4) , Jean-Pierre Blanchet (5) , Aude Boivin-Rioux (6) , Heiko Bozem (7) , Julia Burkart (8) , Rachel Y. W. Chang (9) , Joannie Charette (6) , Jai P. Chaubey (9) , Robert J. Christensen (1) , Ana Cirisan (5) , Douglas B. Collins (10) , Betty Croft (9) , Joelle Dionne (9) , Greg J. Evans (11) , Christopher G. Fletcher (12) , Marti Gali (13) , Roghayeh Ghahremaninezhad (2) , Eric Girard (5) , Wanmin Gong (2) , Michel Gosselin (6) , Margaux Gourdal (14) , Sarah J. Hanna (4) , Hakase Hayashida (15) , Andreas B. Herber (16) , Sareh Hesaraki (17) , Peter Hoor (7) , Lin Huang (2) , Rachel Hussherr (14) , Victoria E. Irish (4) , Setigui A. Keita (5) , John K. Kodros (18) , Franziska Köllner (7, 19) , Felicia Kolonjari (2) , Daniel Kunkel (7) , Luis A. Ladino (20) , Kathy S. Law (21) , Maurice Levasseur (13) , Quentin Libois (5) , John Liggio (22) , Martine Lizotte (13) , Katrina M. Macdonald (11) , Rashed Mahmood (15, 23) , Randall V. Martin (9) , Ryan H. Mason (4) , Lisa A. Miller (24) , Alexander Moravek (1) , Eric Mortenson (15) , Emma L. Mungall (1) , Jennifer G. Murphy (1) , Maryam Namazi (25) , Ann-Lise Norman (26) , Norman T. O'Neill (17) , Jeffrey R. Pierce (18) , Lynn M. Russell (27) , Johannes M. Schneider (19) , Hannes Schulz (16) , Sangeeta Sharma (2) , Meng Si (4) , Ralf M. Staebler (2) , Nadja S. Steiner (24) , Jennie L. Thomas (28, 21) , Knut von Salzen (23) , Jeremy J. B. Wentzell (2) , Megan Willis (29) , Gregory R. Wentworth (30) , Jun-Wei Xu (9) , Jacqueline D. Yakobi-Hancock (31)

1 Department of Chemistry [University of Toronto]
2 ECCC - Environment and Climate Change Canada
3 School of Engineering [Guelph]
4 UBC Chemistry - Department of Chemistry [Vancouver]
5 SCTA - Département des sciences de la terre et de l'atmosphère [Montréal]
6 ISMER - Institut des Sciences de la MER de Rimouski
7 IPA - Institute for Atmospheric Physics [Mainz]
8 Aerosol Physics and Environmental Physics [Vienna]
9 Department of Physics and Atmospheric Science [Halifax]
10 Department of Chemistry [Lewisburg]
11 CHEM ENG - Department of Chemical Engineering and Applied Chemistry
12 Department of Geography and Environmental Management [Waterloo]
13 Department of Biology [Québec]
14 Departement de Biologie [Québec]
15 SEOS - School of Earth and Ocean Sciences [Victoria]
16 AWI - Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine
17 CARTEL - Centre d'Applications et de Recherches en TELédétection [Sherbrooke]
18 Department of Atmospheric Science [Fort Collins]
19 Particle Chemistry Department [Mainz]
20 Centro de Ciencias de la Atmosfera [Mexico]
21 TROPO - LATMOS
22 Air Quality Processes Research Section
23 CCCma - Canadian Centre for Climate Modelling and Analysis
24 IOS - Institute of Ocean Sciences [Sidney]
25 Department of Mathematics [Isfahan]
26 Department of Physics and Astronomy [Calgary]
27 SIO - UC San Diego - Scripps Institution of Oceanography
28 IGE - Institut des Géosciences de l’Environnement
29 LBNL - Lawrence Berkeley National Laboratory [Berkeley]
30 AEP - Alberta Environment and Parks
31 NRC - National Research Council of Canada

Motivated by the need to predict how the Arc-tic atmosphere will change in a warming world, this article summarizes recent advances made by the research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) that contribute to our fundamental understanding of Arctic aerosol particles as they relate to climate forcing. The overall goal of NETCARE research has been to use an in-terdisciplinary approach encompassing extensive field observations and a range of chemical transport, earth system, and biogeochemical models. Several major findings and advances have emerged from NETCARE since its formation in 2013. (1) Unexpectedly high summertime dimethyl sulfide (DMS) levels were identified in ocean water (up to 75 nM) and the overlying atmosphere (up to 1 ppbv) in the Cana-dian Arctic Archipelago (CAA). Furthermore, melt ponds, which are widely prevalent, were identified as an important DMS source (with DMS concentrations of up to 6 nM and a potential contribution to atmospheric DMS of 20 % in the study area). (2) Evidence of widespread particle nucleation and growth in the marine boundary layer was found in the CAA in the summertime, with these events observed on 41 % of days in a 2016 cruise. As well, at Alert, Nunavut, particles that are newly formed and grown under conditions of minimal anthropogenic influence during the months of July and August are estimated to contribute 20 % to 80 % of the 30-50 nm particle number density. DMS-oxidation-driven nucle-ation is facilitated by the presence of atmospheric ammonia arising from seabird-colony emissions, and potentially also from coastal regions, tundra, and biomass burning. Via accumulation of secondary organic aerosol (SOA), a significant fraction of the new particles grow to sizes that are active in cloud droplet formation. Although the gaseous precursors to Arctic marine SOA remain poorly defined, the measured levels of common continental SOA precursors (isoprene and monoterpenes) were low, whereas elevated mixing ratios of oxygenated volatile organic compounds (OVOCs) were inferred to arise via processes involving the sea surface micro-layer. (3) The variability in the vertical distribution of black carbon (BC) under both springtime Arctic haze and more pristine summertime aerosol conditions was observed. Measured particle size distributions and mixing states were used to constrain, for the first time, calculations of aerosol-climate interactions under Arctic conditions. Aircraft-and ground-based measurements were used to better establish the BC source regions that supply the Arctic via long-range transport mechanisms, with evidence for a dominant springtime contribution from eastern and southern Asia to the middle troposphere, and a major contribution from northern Asia to the surface. (4) Measurements of ice nucleating particles (INPs) in the Arctic indicate that a major source of these particles is mineral dust, likely derived from local sources in the summer and long-range transport in the spring. In addition, INPs are abundant in the sea surface microlayer in the Arctic, and possibly play a role in ice nucleation in the atmosphere when mineral dust concentrations are low. (5) Amongst multiple aerosol components, BC was observed to have the smallest effective deposition velocities to high Arctic snow (0.03 cm s −1).

Domaines: Physique Atmosphérique et Océanique [physics.ao-ph]; Climatologie

Jonathan P. D. Abbatt, W. Richard Leaitch, Amir A. Aliabadi, Allan K. Bertram, Jean-Pierre Blanchet, et al.. Overview paper: New insights into aerosol and climate in the Arctic. Atmospheric Chemistry and Physics, 2019, 19 (4), pp.2527-2560. ⟨10.5194/acp-19-2527-2019⟩. ⟨insu-02052254⟩