The evolution of the global aerosol system in a transient climate simulation from 1860 to 2100
Article, Other literature type
Stier , P.
Feichter , J.
Roeckner , E.
Kloster , S.
Esch , M.
- Publisher: European Geosciences Union
(issn: 1680-7324, eissn: 1680-7324)
[ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere | Caltech Library Services
mesheuropmc: respiratory system
The evolution of the global aerosol system from 1860 to 2100 is investigated
through a transient atmosphere-ocean General Circulation Model climate
simulation with interactively coupled atmospheric aerosol and oceanic
biogeochemistry modules. The microphysical aerosol module HAM incorporates
the major global aerosol cycles with prognostic treatment of their
composition, size distribution, and mixing state. Based on an SRES A1B
emission scenario, the global mean sulfate burden is projected to peak in
2020 while black carbon and particulate organic matter show a lagged peak
around 2070. From present day to future conditions the anthropogenic aerosol
burden shifts generally from the northern high-latitudes to the developing
low-latitude source regions with impacts on regional climate. Atmospheric
residence- and aging-times show significant alterations under varying
climatic and pollution conditions. Concurrently, the aerosol mixing state
changes with an increasing aerosol mass fraction residing in the internally
mixed accumulation mode. The associated increase in black carbon causes a
more than threefold increase of its co-single scattering albedo from 1860 to
2100. Mid-visible aerosol optical depth increases from pre-industrial times,
predominantly from the aerosol fine fraction, peaks at 0.26 around the
sulfate peak in 2020 and maintains a high level thereafter, due to the
continuing increase in carbonaceous aerosols. The global mean anthropogenic
top of the atmosphere clear-sky short-wave direct aerosol radiative
perturbation intensifies to −1.1 W m<sup>−2</sup> around 2020 and weakens
after 2050 to −0.6 W m<sup>−2</sup>, owing to an increase in atmospheric
absorption. The demonstrated modifications in the aerosol residence- and
aging-times, the microphysical state, and radiative properties challenge
simplistic approaches to estimate the aerosol radiative effects from emission