AMCATS

Black carbon and methane are believed to be significant climate forcers, but the sizes of their various sources and sinks remain highly uncertain. The Arctic region is known to have large reservoirs of carbon that can potentially be released as methane as the region warms. Black carbon may have a strong influence on snow and ice albedo. The sensitivities of emissions of CH4 and BC to changes in climate are also poorly understood and, therefore, cannot be included with confidence in climate models. Multiple sources of methane and black carbon contribute to concentrations of these species in the Arctic, which complicates the source attribution problem. Measurements of co-emitted species that act as natural tracers for sources of CH4 and BC can help to connect atmospheric concentrations to source emission rates.

The Arctic Methane, Carbon Aerosols, and Tracers Study involves the deployment of instruments to measure CH4, BC, and source tracers. We will deploy three in situ instruments to measure BC (an SP2, our new instrument CALIIOPI, and a PAX). We will also deploy in situ instruments to measure methane and the ratio of its isotopologues 13CH4/12CH4. In addition, we will measure other tracers for its sources, including CO, BC, and volatile organic compounds (using a PTRMS) for combustion sources and ethane for petroleum sources. Changes in emissions across different regions and seasons will be inferred using atmospheric transport and inverse techniques modeling.