Assessment of Black Carbon in Snow and Ice from the Tibetan Plateau and Pacific Northwest

Matthew Glen Jenkins
December 2011

Abstract

An ice core from Mt. Geladandong, Tibetan Plateau, spanning 1853-1983, and snow samples collected over two winters from the Cascade Mountains were analyzed for concentrations of black carbon (BC) using a Single Particle Soot Photometer (SP2). From the ice core, the high-resolution BC record displayed substantial variability, a 2-fold increase in peak concentrations from 1853-1930 to 1930-1983, and a 1.6-fold increase in average concentrations from 1853-1975 to 1975-1983. Concentrations were also higher than at two areas closer to BC sources and analyzed by the same method. In the Pacific Northwest, BC concentrations varied seasonally and annually, with the highest concentrations in the first winter (2010) and spring of both years. Estimates for BC-induced reductions in albedo ranged from 0.1-5.5% for both sites, and may be high enough to impact on snow, ice, and water resources when analytical uncertainties, the timing of reductions, and the potential for feedback cycles are considered.

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