Regional Impacts of Aerosols on Convection: Using Satellite and Reanalysis data to Isolate Aerosol Effects

The impact of aerosols on the microphysical and dynamic properties of clouds has been much debated since the introduction of the first and second aerosol indirect effects. Many studies have examined both the modeling and observational sides of aerosol-cloud interactions. The buffering effect of the surrounding environment on individual clouds makes it difficult to isolate the effects of aerosols, particularly at larger spatial and temporal scales. This study uses observations from the Tropical Rainfall Measuring Mission (TRMM), CloudSat, and Aqua satellites to identify convective clouds systems in clean and dirty environments. MODIS aerosol index is collocated with radar precipitation features (RPFs) from TRMM and congestus cloud features (CFs) from Cloudsat. These features are then used to examine the characteristics of clouds occurring in clean and dirty environments in different parts of the world. The ERA-Interim, which is paired with RPFs and CFs, is used to examine the environment in which these clean and dirty features occur. In this study, we show evidence that aerosols have different effects on clouds in different parts of the world. In some regions, results point toward environmental differences that may explain "invigoration" that has been attributed to aerosol effects in other studies. In other regions, environmental differences between clean and dirty cloud features are found to be small, indicating that the observed differences in cloud properties may indeed be attributed to aerosol effects.