1International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Drive, Fairbanks, Alaska, 99775, USA
2Department of Atmospheric Sciences, University of Alaska Fairbanks, 930 Koyukuk Drive, Fairbanks, Alaska, 99775, USA
3Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, Alaska, 99775, USA
4Department of Earth System Science, University of Fukuoka, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
5Department of Physics, University of Alaska Fairbanks, P.O. Box 755920, Fairbanks, AK 99775-5920, USA
6Department of Chemistry, University of Alaska Fairbanks, P.O. Box 755920, Fairbanks, AK 99775-5920, USA
7Department of Meteorology, The Florida State University, Dept. of Meteorology/404 LOV, 1017 Academic Way/P.O. Box 3064520, Tallahassee, FL 32306-4520, USA
*present address: Department of Geography, University of Victoria, P.O. Box 3060 STN CSC, Victoria, BC, V8W 3R4, Canada
Received: 20 Apr 2011 – Published in Atmos. Chem. Phys. Discuss.: 10 Jun 2011
Abstract. Aerosol loading over Interior Alaska displays a strong seasonality, with pristine conditions generally prevailing during winter months. Long term aerosol research from the University of Alaska Fairbanks indicates that the period around April typically marks the beginning of the transition from winter to summer conditions. In April 2008, the NASA-sponsored "Arctic Research of the Composition of the Troposphere from Aircraft and Satellites" (ARCTAS) field campaign was conducted to analyze incursions of aerosols transported over Alaska and the Canadian North. In and around Fairbanks, Alaska, data concerning aerosol characteristics were gathered by polarization (0.693 μm) lidar, DRUM Impactor sampler, and balloon-borne optical particle counter. These data provide information on the vertical distribution and type of aerosol, their size distributions, the chemical nature of aerosol observed at the surface, and timing of aerosol loading. A detailed synoptic analysis placed these observations into their transport and source-region context. Evidence suggests four major aerosol loading periods in the 25 March–30 April 2008 timeframe: a period during which typical Arctic haze conditions prevailed, several days of extremely clear conditions, rapid onset of a period dominated by Asian dust with some smoke, and a period dominated by Siberian wildfire smoke. A focused case study analysis conducted on 19 April 2008 using a balloon-borne optical particle counter suggests that, on this day, the majority of the suspended particulate matter consisted of coarse mode desiccated aerosol having undergone long-range transport. Backtrack trajectory analysis suggests aged Siberian wildfire smoke. In the last week of April, concentrations gradually decreased as synoptic conditions shifted away from favoring transport to Alaska. An important result is a strong suggestion of an Asian dust incursion in mid-April that was not well identified in other ARCTAS measurements. The lidar and OPC-sonde unambiguously discern aerosols height stratification patterns indicative of long range transport. Identification of a dust component is suggested by DRUM sampler results, which indicate crustal species, and supported by synoptic and trajectory analysis, which indicates both a source-region lifting event and appropriate air-mass pathways.
Revised: 11 Dec 2012 – Accepted: 14 Dec 2012 – Published: 01 Feb 2013
Atkinson, D. E., Sassen, K., Hayashi, M., Cahill, C. F., Shaw, G., Harrigan, D., and Fuelberg, H.: Aerosol properties over Interior Alaska from lidar, DRUM Impactor sampler, and OPC-sonde measurements and their meteorological context during ARCTAS-A, April 2008, Atmos. Chem. Phys., 13, 1293-1310, doi:10.5194/acp-13-1293-2013, 2013.