Climatology and Characteristics of In-situ Aerosol Optical Properties in the Arctic

Tuesday, 15 December 2015: 17:30
3010 (Moscone West)
John A Ogren1, Lauren Schmeisser1,2, Sangeeta Sharma3, Eija Asmi4, Michael Howard Bergin5, Anne Jefferson6, Elisabeth Andrews6, Peter Tunved7 and John Backman4, (1)NOAA Boulder, ESRL/GMD, Boulder, CO, United States, (2)University of Washington Seattle Campus, Seattle, WA, United States, (3)Environment Canada, Toronto, ON, Canada, (4)Finnish Meteorological Institute, Helsinki, Finland, (5)Georgia Inst Tech, Atlanta, GA, United States, (6)University of Colorado at Boulder, Boulder, CO, United States, (7)Stockholm University, Stockholm, Sweden
Within the Arctic, climate forcers like atmospheric aerosols are important contributors to the observed warming and environmental changes in the region. Quantifying the forcing by aerosols in the Arctic is especially difficult, given short aerosol lifetimes, annual variability in illumination and surface albedo, stratified atmospheric conditions, complex feedbacks, and long-range aerosol transport. However, in-situ surface measurements of Arctic aerosol optical properties can be used to constrain variability of light scattering and absorption, identify potential particle sources, and help evaluate the resulting forcing. Data from six WMO Global Atmosphere Watch stations are presented: Alert, Canada (ALT); Barrow, Alaska (BRW); Pallas, Finland (PAL); Summit, Greenland (SUM); Tiksi, Russia (TIK); and Zeppelin Mountain, Norway (ZEP). These sites contribute to the International Arctic System for Observing the Atmosphere (IASOA), which facilitates Arctic-wide data collection and analysis. Climatologies of aerosol optical properties from each station show differences in magnitude and variability of observed parameters. For example, Figure 1 presents the annual cycle of aerosol light scattering at 550 nm at each site for 2012-2014, with most stations (ALT, BRW, TIK, ZEP) experiencing maximum scattering in winter/spring, while SUM and PAL exhibit minimum scattering in the winter. The observed range in scattering across these sites is large (almost an order of magnitude) - SUM has the lowest annual median scattering at 0.82 Mm-1 while BRW has the highest at 6.9 Mm-1. A closer look at systematic variability between optical properties at each station, as well as site back trajectories, suggest differences in aerosol processes, sources and transport. The development of consistent climatologies and additional analyses like the ones presented here can help provide a better understanding of trans-Arctic aerosol variability, which can be an asset for improving aerosol models in this remote region.