Comparison of Cumulus Cloud Microphysical Properties Inside and Outside Plumes of Biomass Burning and Anthropogenic Aerosols: Results from CAMP2Ex

The influence of biomass burning (BB) and anthropogenic aerosols on clouds represents one of the largest uncertainties in radiative forcings of the climate system. In 2019, a NASA-funded field campaign, the Cloud, Aerosol and Monsoon Processes Philippines Experiment (CAMP2Ex) based in South East Asia, sampled three distinct regions around the Philippines, the West Pacific, the South China Sea, and the Sulu Sea. The aerosols and clouds located in these three areas were sampled by instruments mounted on the NASA P3 aircraft that measured the optical and microphysical properties of clouds and aerosols. Cumulus clouds, which are common over maritime regions impacted by BB or anthropogenic aerosols, are important regulators of the global radiative energy budget and global hydrologic cycle. Analyses of in-situ aircraft sampled microphysical properties from CAMP2Ex quantified the cloud microphysical properties within and outside BB aerosol and anthropogenic aerosol plumes from which information on cloud-aerosol interactions could be inferred. During CAMP2Ex the NASA P3 penetrated 1698 boundary layer linked clouds just above cloud base. The cloud diameters ranged from 0.11 km to 4.5 km with most clouds in the range of 0.2 - 0.3 km. The cloud droplet concentrations ranged from 171.4 to 1971.6 cm-3 with the smallest number concentration found in marine cumulus outside the region of BB plumes and aerosol plumes originating from anthropogenic and natural sources of the Asian continent. The mean number concentration within the BB and aerosol plumes ranged between 440.7 to 1064.6 cm-3 and 93.9 to 229.6 cm-3 outside of the aerosol plumes. The highest particle concentrations were within BB plumes. Similarities and differences in cloud number concentrations (Nd), effective radii (re), liquid water content (LWC), aerosol concentrations (Na), aerosol size distributions and cloud particle size distributions near cloud base, relative to compositional and physical differences observed in boundary layer aerosols and cloud regimes, will be discussed.