Potential sources of black carbon during CHINARE summer shipborne surveys in the Arctic Ocean

Black carbon (BC) aerosols are considered key factors that contribute to rapid climate warming and ice melt in the Arctic region. However, compared with long-term observations from land-based stations, observational data over the Arctic Ocean remain relatively scarce. Four Arctic scientific expeditions were conducted in the summer and early autumn of 2010, 2012, 2016, and 2018 via the Chinese research vessel Xue Long, during which the BC concentrations along the routes were measured via light absorption methods. In this work, the spatiotemporal distribution characteristics of BC over the Arctic Ocean were examined on the basis of these observations. The potential sources of BC along the various routes were analyzed via the weighted potential source contribution function and weighted concentration-weighted trajectory methods of the hybrid single-particle Lagrangian integrated trajectory model in conjunction with Arctic transport potential climate model simulations. The analysis results indicated that wildfires in the western Aleutian Islands, Siberia, and Far East regions were the primary contributors to the BC aerosol concentration observed along the Arctic expedition routes in summer, identifying these regions as major potential source areas.