Sensitivity of aerosol and cloud effects on radiation to cloud types: comparison between deep convective clouds and warm stratiform clouds over one-day period

摘要

Cloud and aerosol effects on radiation in two contrasting cloud types, adeep mesoscale convective system (MCS) and warm stratocumulus clouds, aresimulated and compared. At the top of the atmosphere, 45–81% ofshortwave cloud forcing (SCF) is offset by longwave cloud forcing (LCF) inthe MCS, whereas warm stratiform clouds show the offset of less than ~20%. 28% of increased negative SCF is offset by increased LCF withincreasing aerosols in the MCS at the top of the atmosphere. However, thestratiform clouds show the offset of just around 2–5%. Ice clouds aswell as liquid clouds play an important role in the larger offset in theMCS. Lower cloud-top height and cloud depth, characterizing cloud types,lead to the smaller offset of SCF by LCF and the offset of increasednegative SCF by increased LCF at high aerosol in stratocumulus clouds thanin the MCS. Supplementary simulations show that this dependence ofmodulation of LCF on cloud depth and cloud-top height is also simulatedamong different types of convective clouds.