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Publication Date
1 June 2012

Potential aerosol indirect effects on atmospheric circulation and radiative forcing through deep convection



Aerosol indirect effects (i.e., the interactions of aerosols with clouds by serving as cloud condensation nuclei or ice nuclei) constitute the largest uncertainty in climate forcing and projection. The previous Intergovernmental Panel on Climate Change reported negative aerosol indirect forcing, which does not account for aerosol convective cloud interactions because the complex processes involved are poorly understood and represented in climate models. Here, we elucidated how aerosols change convective intensity, diabatic heating, and regional circulation under different environmental conditions. We found that aerosol indirect effects on deep convective cloud systems could lead to enhanced regional convergence and a strong top-of-atmosphere warming. Aerosol invigoration effect occurs mainly in warmed-based convection with weak shear. This could result in a strong radiative warming in the atmosphere (up to +5.6 W m-2), a lofted latent heating, and a reduced diurnal temperature difference, all of which could potentially impact regional circulation and modify weather systems. The positive aerosol radiative forcing on deep clouds could offset the negative aerosol radiative forcing on low clouds to an unknown extent.

“Potential Aerosol Indirect Effects On Atmospheric Circulation And Radiative Forcing Through Deep Convection”. 2012. Geophysical Research Letters, L09806. doi:10.1029/ 2012GL051851.
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