Aerosol Impacts on Deep Convective Storms

Cloud condensation nuclei (CCNs) are vital for the formation of cloud droplets. Yet, their effect on precipitation is far from understood. For warm rain processes, excess CCN are thought to lead to competition for available cloud water and strong evidence exist that cloud droplets becomes smaller. Beyond this, however, there are a number of pathways for clouds to grow and precipitate and specific outcomes depend strongly on atmospheric stability. For cold processes the situation is even less clear although arguments have been put forth in the literature that a suppression of warm rain processes can indeed enhance the convective strength of deeper clouds. In this study, we look at aerosol concentration derived from the Goddard Earth Observing System (GEOS) model coupled with a chemical transport model and an aerosol extension module (GEOS-Chem-TOMAS) together with dual frequency radar data from the Global Precipitation Measurement (GPM) Dual Frequency Radar (DPR) profiles to assess if convective invigoration can be observed on a large scale. Aerosols and precipitation structures are examined over CONUS for a one year period. The study shows that stronger convection can indeed be observed with higher aerosol concentration irrespective of location, CAPE, wind shear or mid-level humidity. Meteorological background fields are obtained from ERA-Interim for the same period.