Observations of Deep Convective Cloud Properties and their Modifications by Aerosols

We present results from our recent advances in studying the issue of aerosol-deep convective cloud (DCC) interactions. I first explain a conceptual model of cloud particle evolution inside deep convective clouds and present observational evidence for it. We find a robust relationship between ice particle size (IPS) and cloud brightness temperature (BT) of deep convective clouds. Important inference like cloud glaciation temperature can be made to the IPS-BT profiles. With the physical relationship and inferences from the profiles we investigate how aerosol could change DCC micro- and macro- physical properties. Under two scenarios we identified, smoke aerosols and pollutions are shown in decrease IPS of DCCs. Through case and ensemble statistics we also show aerosols can reduce glaciation temperature of DCCs. A robust correlation is identified between aerosol loading and glaciation temperature of clouds. Analysis of TRMM data also seems to agree with the notion that convection is invigorated as a result of this interaction. Dust particles, on the hand, are found to have just the opposite effect. Furthermore, we present evidences of aerosol changing lightning characteristics of maritime convection. The observed scarce lightning, ample convection (SLAC) paradox may be partly contributed by the clean environment of the maritime ocean. We show that a 60% of increase in aerosol loading can lead to a 100% increase in lightning activity. Moreover, we show evidences of increased tropospheric ozone concentration as a result of this aerosol effect. Important implications and applications are discussed for our results.