Ice core records of biomass burning tracers (levoglucosan, dehydroabietic and vanillic acids) from Aurora Peak in Alaska since 1660s: A new dimension of forest fire activities in the Northern Hemisphere

Abstract

<p><strong>Abstract.</strong> A 180 m long (ca. 274 years) ice core was drilled in the saddle of the Aurora Peak of Alaska (63.52° N; 146.54° W, elevation: 2825 m). The ice core samples were melt, concentrated and then derivatized with N,O-bis-(trimethylsilyl) trifluoroacetamide with 1 % trimethylsilyl chloride and pyridine followed by gas chromatography/mass spectrometry analyses. Levoglucosan, dehydroabietic acid, and vanillic acid are reported for the first time from the alpine glacier to better understand historical biomass burning activities in the source region of southern Alaska. These organic compounds showed higher concentrations with many sporadic peaks in the 1660s–1830s, 1913, and 2005. Moreover, there are few discrepancies of higher spikes among them after the 1970s with sporadic peaks in 1994–2007 for dehydroabietic acid. Historical trends of levoglucosan, dehydroabietic and vanillic acid showed that biomass burning activities from resin and lignin in boreal conifer trees, other higher plants and grasses were significant before the 1840s and after the 1970s in the source regions of southern Alaska, being different from previous ice core studies. Long-range atmospheric transport could be important for levoglucosan compared to dehydroabietic acid in the North Pacific Rim (NPR). We found weak or no correlations of levoglucosan with NO<sub>2</sub><sup>−</sup> (r = 0.06), NO<sub>3</sub><sup>−</sup> (0.04), nss-SO<sub>4</sub><sup>2−</sup> (0.08), nss-K<sup>+</sup> (0.11), and NH<sub>4</sub><sup>+</sup> (0.11) from the same ice core, suggesting that these anions and cations do not represent a gleaming signal of biomass burning activities in the source regions for southern Alaska. Hence, this study revels a new dimension of biomass burning periodic cycles in the NPR.</p>

Photodecay of guaiacol is faster in ice, and even more rapid on ice, than in aqueous solution

“…Guaiacol is one of the many aromatic compounds emitted by biomass burning, which is a significant source of organics to remote polar regions. [56][57][58][59] To understand what our experimental results mean for the lifetimes of guaiacol in polar snow, we calculated guaiacol photodegradation rate constants for Summit, Greenland under summer solstice sunlight. We used equation with:…”

Alpine snowpit profiles of polar organic compounds from Mt. Tateyama central Japan: Atmospheric transport of organic pollutants with Asian dust

“…Terrestrial higher plants to marine phytoplanktons emitted huge amounts of biogenic VOCs, which are 10 times larger than anthropogenic VOCs on a global scale (Seinfeld and Pandis, 1998). Biogenic and anthropogenic VOCs are oxidized in the atmosphere to result in secondary organic aerosols (SOA), which are further oxidized to diacids, oxoacids, glyoxal, and methylglyoxal via heterogeneous reactions (Talbot et al, 1995;Lim et al, 2005;Volkamer et al, 2009;Kunwar and Kawamura, 2014a,b;Pokhrel et al, 2019). Carlton et al (2006Carlton et al ( , 2007 and Zhu et al (2015) reported that primary organic aerosols (POA) are emitted from plants, fungal spore, fossil fuel combustion, biomass burning, and soil particles, whereas SOA are photochemically produced by heterogeneous oxidations of biogenic and anthropogenic VOCs (Surratt et al, 2010;Ho et al, 2010;Kundu et al, 2010).…”