Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 8 4 2008 10.5194/acpd-8-15291-2008 http://www.atmos-chem-phys-discuss.net/8/15291/2008/ http://www.atmos-chem-phys-discuss.net/8/15291/2008/acpd-8-15291-2008.html http://www.atmos-chem-phys-discuss.net/8/15291/2008/acpd-8-15291-2008.pdf 15291 15341 2008-08-12 Cloud and aerosol effects on radiation in deep convective clouds: comparison with warm stratiform clouds S. S. Lee seoungl@umich.edu L. J. Donner V. T. J. Phillips Geophysical Fluid Dynamics Laboratory, Princeton University, Princeton, NJ, USA now at: Department of Atmospheric, Oceanic, and Space Science, University of Michigan, Ann Arbor, MI, USA now at: Department of Meteorology, University of Hawaii, Manoa, HI, USA Cloud and aerosol effects on radiation in two contrasting cloud types, a deep convective mesoscale cloud ensemble (MCE) and warm stratocumulus clouds, are simulated and compared. At the top of the atmosphere, 45–81% of shortwave cloud forcing (SCF) is offset by longwave cloud forcing (LCF) in the MCE, whereas warm stratiform clouds show the offset of less than ~20%. 28% of increased negative SCF is offset by increased LCF with increasing aerosols in the MCE at the top of the atmosphere. However, the stratiform clouds show the offset of just around 2–5%. Ice clouds as well as liquid clouds play an important role in the larger offset in the MCE. Hence, this study indicates effects of deep convective clouds on radiation and responses of deep convective clouds to aerosols are quite different from those of shallow clouds through the different modulation of longwave radiation; the presence of ice clouds in deep convective clouds contributes to the different modulation of longwave radiation significantly. 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