Publication Date:
2018-05-14
Description:
Atmospheric aging promotes internal mixing of black carbon (BC) leading to an enhancement of light absorption and radiative forcing. The relationship between BC mixing state and consequent absorption enhancement was never estimated for BC found in the Arctic region. In the present work, we aim to quantify the absorption enhancement and its impact on radiative forcing as a function of microphysical properties and mixing state of BC observed in-situ at the Zeppelin Arctic station (78°N) in the spring of 2012 during the CLIMSLIP (Climate impacts of short-lived pollutants in the Arctic) project. Single particle soot photometer (SP2) measurements showed a mean mass concentration of refractory black carbon (rBC) of 39ngm−3, while the rBC mass size distribution was of log-normal shape peaking at an rBC mass equivalent diameter (DrBC) of around 240nm. On average, the number fraction of particles containing a BC core with DrBC〉80nm was less than 5% in the size range (overall optical particle diameter) from 150–500nm. The BC cores were internally mixed with other particulate matter. The median coating thickness of BC cores with 220nm
Electronic ISSN:
1680-7375
Topics:
Geosciences