Incandescence-based single-particle method for black carbon quantification in lake sediment cores

Refractory black carbon (rBC) is an important contributor to radiative forcing, so quantifying rBC emissions and transport is critical for accurate climate modeling. Formed during incomplete combustion of fossil fuels or biofuels, rBC is emitted to the atmosphere from large wildfires and industrial sources where it can be transported and deposited globally. Ice cores have been used to reconstruct historical changes in biomass burning and industrial emissions but they are available only from glaciers and ice sheets, with reliable records longer than a few centuries generally limited to polar regions. Lake sediment cores provide a possible alternative to develop longer term, widely distributed records from mid- and low-latitude regions, albeit with lower temporal resolution and less directly linked to atmospheric concentrations than ice-core rBC records. Here, we present a new incandescence-based method for measuring rBC in lake sediment cores using the Single-Particle Soot Photometer. Compared to existing filter-based techniques, this highly sensitive method requires a much smaller sample size, resulting in reproducible, relatively high-temporal-resolution records of past rBC deposition.