A 3‐year record of simultaneously measured aerosol chemical and optical properties at Barrow, Alaska

Abstract

[1] Results are presented from 3 years of simultaneous measurements of aerosol chemical composition and light scattering and absorption at Barrow, Alaska. All results are reported at the measurement relative humidity of 40%. Reported are the annual cycles of the concentration of aerosol mass, sea salt, non-sea-salt (nss) sulfate, methanesulfonate or MSA À , NH 4 + , and nss K + , Mg +2 , and Ca +2 for the submicron and supermicron size ranges. Submicron nss SO 4 = , NH 4 + , and nss K + , Mg +2 , and Ca +2 peak in winter and early spring corresponding to the arrival and persistence of Arctic Haze. Submicron sea salt displays a similar annual cycle presumably due to long-range transport from the northern Pacific Ocean. Supermicron sea salt peaks in summer corresponding to a decrease in sea ice extent. Submicron and supermicron MSA À peak in the summer due to a seasonal increase in the flux of dimethylsulfide from the ocean to the atmosphere. A correlation of MSA À and particle number concentrations suggests that summertime particle production is associated with this biogenic sulfur. Mass fractions of the dominant chemical species were calculated from the concentrations of aerosol mass and chemical species. For the submicron size range the ionic mass and associated water make up 80 to 90% of the aerosol mass from November to May. Of this ionic mass, sea salt and nss SO 4 = are the dominant species. The residual mass fraction, or fraction of mass that is chemically unanalyzed, is equivalent to the ionic mass fraction in June through October. For the supermicron size range the ionic mass and associated water make up 60 to 80% of the aerosol mass throughout the year with sea salt being the dominant species. Also reported for the submicron size range are the annual cycles of aerosol light scattering and absorption at 550 nm, Å ngström exponent for the 450 and 700 nm wavelength pair, and single scattering albedo at 550 nm. On the basis of linear regressions between the concentrations of sea salt and nss SO 4 = and the light scattering coefficient, sea salt has a dominant role in controlling light scattering during the winter, nss SO 4 = is dominant in the spring, and both components contribute to scattering in the summer. Submicron mass scattering efficiencies of the dominant aerosol chemical components (nss SO 4 = , sea salt, and residual mass) were calculated from a multiple linear regression of the measured light scattering versus the component concentrations. Submicron nss SO 4 = mass scattering efficiencies were relatively constant throughout the year with seasonal averages ranging from 4.1 ± 2.9 to 5.8 ± 1.0 m 2 g À1 . Seasonal averages for submicron sea salt ranged from 1.8 ± 0.37 to 5.1 ± 0.97 m 2 g À1 and for the residual mass ranged from 0.21 ± 0.31 to 1.5 ± 1.0 m 2 g À1 . Finally, concentrations of nss SO 4 = measured at Barrow were compared to those measured at Poker Flat Rocket Range, Denali National Park, and Homer for the 1997/1998 and 1998/1999 Arctic Haze seasons. Concentrations were highest at Barrow ...

Measurements of aerosol and CCN properties in the Mackenzie River delta (Canadian Arctic) during spring–summer transition in May 2014

“…8b. The monomodal accumulation-mode aerosol is characteristic for the Arctic haze, which mainly consists of POM and sulfate (Quinn et al, 2002). Single particle analysis of aerosol particles samples taken at the Zeppelin Observatory, Svalbard, that occurred before the transition to the Arctic summer showed a dominance of spherical organic-like particles in the submicrometer range with an Eurasian influence (Behrenfeld et al, 2008).…”

“…Hence the so-called Arctic haze can be trapped for 15 to 30 days (Shaw, 1981(Shaw, , 1995. The major part of the Arctic haze consists of particulate organic matter (POM) and sulfate but also contains ammonium, nitrate, mineral dust, black carbon and heavy metals (Quinn et al, 2002). Reported PNSDs show an accumulation mode with N CN constantly increasing during the winter months from October until April from below 50 to above 200 cm −3 (Tunved et al, 2013).…”

An update on polar aerosol optical properties using POLAR-AOD and other measurements performed during the International Polar Year

“…For this purpose, an evaluation of the mass fractions of the main particulate chemical components was performed, by taking into account the results found by Quinn et al (2002), who examined a 3-year set of simultaneous measurements of aerosol chemical composition and light scattering and absorption measurements performed at Barrow from October 1997 to December 2000, for rather low relative humidity conditions. These estimates were given by Quinn et al (2007) in terms of monthly mean concentrations of aerosol mass constituents, such as sea salt, non-sea salt (nss) sulphate, methane sulphonic acid (MSA), ammonium ions, and nss K, Mg and Ca ions, for both the submicron and supermicron size ranges.…”

Source Sector and Region Contributions to Black Carbon and PM<sub>2.5</sub> in the Arctic

“…Several studies, 10 as early as the 1980s, reported a distinctive seasonal cycle in the Arctic aerosol and BC concentration and visibility (Barrie, 1986;Quinn et al, 2007;Rosen et al, 1981;Schnell, 1984;Wang et al, 2011). The so-called Arctic Haze phenomenon in the winter-spring period has been attributed to increased levels of transported Particulate Matter (PM) from anthropogenic emission sources at lower latitudes and slower wet deposition removal processes (Barrie et al, 1981;Law and Stohl, 2007;Quinn et al, 2002Quinn et al, , 2007.…”