1Geophysical 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
Received: 27 May 2008 – Published in Atmos. Chem. Phys. Discuss.: 12 Aug 2008 – Published: 08 Apr 2009
Abstract. Cloud and aerosol effects on radiation in two contrasting cloud types, a deep mesoscale convective system (MCS) 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 MCS, 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 MCS 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 MCS. Lower cloud-top height and cloud depth, characterizing cloud types, lead to the smaller offset of SCF by LCF and the offset of increased negative SCF by increased LCF at high aerosol in stratocumulus clouds than in the MCS. Supplementary simulations show that this dependence of modulation of LCF on cloud depth and cloud-top height is also simulated among different types of convective clouds.
Lee, S. S., Donner, L. J., and Phillips, V. T. J.: Sensitivity of aerosol and cloud effects on radiation to cloud types: comparison between deep convective clouds and warm stratiform clouds over one-day period, Atmos. Chem. Phys., 9, 2555-2575, doi:10.5194/acp-9-2555-2009, 2009.