Enhanced light absorption by mixed source black and brown carbon particles in UK winter
S Liu
AC Aiken
K Gorkowski
MK Dubey
CD Cappa
LR Williams
SC Herndon
P Massoli
EC Fortner
PS Chhabra
WA Brooks
TB Onasch
JT Jayne
DR Worsnop
S China
N Sharma
C Mazzoleni
L Xu
NL Ng
D Liu
JD Allan
JD Lee
ZL Fleming
C Mohr
P Zotter
S Szidat
ASH Prévôt
2381/45828
https://figshare.le.ac.uk/articles/journal_contribution/Enhanced_light_absorption_by_mixed_source_black_and_brown_carbon_particles_in_UK_winter/10216352
Black carbon (BC) and light-absorbing organic carbon (brown carbon, BrC) play key roles in warming the atmosphere, but the magnitude of their effects remains highly uncertain. Theoretical modelling and laboratory experiments demonstrate that coatings on BC can enhance BC’s light absorption, therefore many climate models simply assume enhanced BC absorption by a factor of ∼1.5. However, recent field observations show negligible absorption enhancement, implying models may overestimate BC’s warming. Here we report direct evidence of substantial field-measured BC absorption enhancement, with the magnitude strongly depending on BC coating amount. Increases in BC coating result from a combination of changing sources and photochemical aging processes. When the influence of BrC is accounted for, observationally constrained model calculations of the BC absorption enhancement can be reconciled with the observations. We conclude that the influence of coatings on BC absorption should be treated as a source and regionally specific parameter in climate models.
2019-10-02 14:40:57
Atmospheric science
Climate-change impacts