This is a past event.

Going Beyond the Conventional Paradigm to Address Aerosol-cloud Interactions

Despite decades of research and progress, climate models still suffer from large uncertainty in estimated aerosol indirect effects and large discrepancy with observations. Understanding of aerosol-cloud interactions (ACI) and their representation in climate models still pose vital challenges even for the simplest of all clouds − non-precipitating warm clouds. In this seminar, I will show, by combining observational, theoretical, and modeling analyses, that addressing the remaining issues calls for going beyond the conventional paradigm of investigation (e.g., adiabatic clouds, droplet concentration centered, aerosol-limited and transitional regime). Specifically, I will first discuss several potentially important yet poorly understood factors/processes that likely compensate/buffer aerosol-cloud interactions as conventionally represented in climate models, with an emphasis on 1) dispersion effect associated with the aerosol-induced changes of the spectral shape of the cloud droplet size distribution; 2) regime dependence of ACI on aerosol concentration and updraft velocity; 3) effect of turbulent entrainment-mixing processes, and microphysics-turbulence interactions; 4) process coupling. I will then explore the knowledge gaps that need to fill for further advancement, and the challenges to address them. Finally, I will share some results and thought on using our particle-resolved direct numerical simulation (DNS) model and machine learning to fill the knowledge gaps and address the remaining challenges.