Copernicus Publications on behalf of the European Geophysical Society
Abstract
Particulate solar absorption is a critical factor in determining the value and even sign
of the direct radiative forcing of aerosols. The heating to the atmosphere and cooling
to the Earth’s surface caused by this absorption are hypothesized to have significant
climate impacts. We find that anthropogenic aerosols play an important role around
the globe in total particulate absorption of solar radiation. The global-average anthropogenic
fraction in total aerosol absorbing optical depth exceeds 65% in all seasons.
Combining the potentially highest dust absorption with the lowest anthropogenic absorption
within our model range, this fraction would still exceed 47% in most seasons
except for boreal spring (36%) when dust abundance reaches its peak. Nevertheless,
dust aerosol is still a critical absorbing constituent over places including North Africa,
the entire tropical Atlantic, and during boreal spring in most part of Eurasian continent.
The equality in absorbing solar radiation of dust and anthropogenic aerosols appears
to be particularly important over Indian subcontinent and nearby regions as well as
North Africa.National Science Foundation (U.S.) (ATM-0329759)United States. National Aeronautics and Space Administration (NNX07AI49G)Massachusetts Institute of Technology. Joint Program on the Science & Policy of Global Chang
