Multidecadal trends in aerosol radiative forcing over the Arctic: Contribution of changes in anthropogenic aerosol to Arctic warming since 1980

摘要: Arctic observations show large decreases in the concentrations of sulfate and black carbon (BC) aerosols since early 1980s. These near-term climate-forcing pollutants perturb radiative balance atmosphere may have played an important role recent warming. We use GEOS-Chem global chemical transport model to construct a 3-D representation that is generally consistent with their trends from 1980 2010. Observations at surface sites significant BC mass 2–3% per year. find anthropogenic yield negative forcing over Arctic, average 2005–2010 shortwave (RF) −0.19 ± 0.05 W m−2 top (TOA). Anthropogenic our study yields more strongly forcings troposphere spring (−1.17 ± 0.10 W m−2) than previously reported. From 2010, TOA RF by aerosol declined, −0.67 ± 0.06 W m−2 −0.19 ± 0.05 W m−2, yielding net +0.48 ± 0.06 W m−2. The positive due almost entirely loading Arctic. estimate 1980–2010 aerosol-radiation interactions Northern Hemisphere midlatitudes contributed warming +0.27 ± 0.04 K, roughly one quarter observed Our does not consider emissions gas flaring nor regional climate response aerosol-cloud or deposition on snow.