Study by Yi Ming and co-authors on the
Two opposing effects of absorbing aerosols on global-mean precipitation
Absorbing aerosols, such as black
carbon, which alter the Earth?s climate by absorbing solar radiation, may
suppress precipitation to some extent, a model-supported analysis of the global-mean
atmospheric energy budget coauthored by Yi Ming, V. Ramaswamy and Geeta Persad
they heat up both the atmosphere and the surface, absorbing aerosols affect
precipitation in opposite ways. When simulating with a coupled general
circulation-ocean model the overall hydrological response to increased black
carbon levels, the researchers found that the net effect on global-mean
precipitation is slightly negative.The effect is too small to outweigh the
2-3 % increase in global precipitation per each degree of greenhouse warming.
But absorbing aerosols could have a more pronounced impact on moist convection
and general circulation than carbon dioxide and non-absorbing aerosols, such as
sulfate, which merely scatter solar radiation, the authors suggest.
plot (crosses) of relative changes in precipitation (%) due to black
carbon simulated with the model (x-axis) and predicted with a theory
(y-axis, see the paper for detail). The Figure was created with help from Jeffrey Varanyak.
To read more: Ming et al., 2010