Investigating fire frequency and vegetative combustion sources using wildland fire tracer molecules archived in the Juneau Icefield of Alaska

The past decade includes some of the most extensive boreal forest fires in the historical record. Environmental drivers include warming temperatures, changing precipitation patterns, desiccation of thick organic soil layers, and increased ignition frequency from lightning. Wildland fires produce smoke aerosols that can travel thousands of kilometers, before blanketing the surfaces on which they fall, such as the Juneau Icefield of Alaska. This data release presents chemical constituent and physical particulate results from investigations of wildland fire smoke deposits and other atmospheric deposition characteristics stored in layers of ice in the Juneau Icefield of Alaska, USA (Tables 1 and 2). We drilled a series of four firn cores in summer of 2016 and two cores in summer of 2017 in cooperation with the Juneau Icefield Research Program (JIRP). The ice core sampling locations are shown in the Juneau Icefield Alaska Map jpg graphic. The JIRP cores comprise a transect that spans the high-precipitation southwestern slopes of the Juneau Icefield (Lemon Creek and Taku Glaciers), to the relatively drier sites of the central plateau (Matthes Glacier), and ends at the top of the Llewellyn Glacier, which is experiencing some of the most dramatic melt on the entire icefield. A new gas chromatography tandem mass spectrometry method was developed to analyze all ice core samples (2016 and 2017) for monosaccharide anhydrides, which are unique molecular identifiers of biomass combustion, rather than fossil fuel combustion (Tables 3 and 4). The 2016 ice samples were also analyzed for major ions, particle counts, and stable isotopes of oxygen and hydrogen in water which are also present in this data release (Table 4).