Aerosol‐Cloud Interactions in Warm Clouds Using Advanced Causal Discovery

Abstract

Aerosol-cloud interactions play a crucial role in determining properties and evolution of marine boundary layer clouds. These clouds cover roughly one-third of the global oceans, and thus have a significant impact on the climate system via their effects on radiation in the Earth’s atmosphere. Many meteorological processes are involved in aerosol-cloud interactions. Central to these is that changes in aerosol will lead to changes in cloud and precipitation development, and through those on the radiative effect of the clouds. Although the complex impacts of aerosols have been studied extensively using observations and model simulations, quantitative estimates of how the aerosols influence cloud evolution, the so-called causal pathways, are still lacking.

We propose to study aerosol-cloud interactions by establishing a complete causal network based on a new causal discovery framework developed by the PI. To achieve this goal, we will construct timeseries of atmospheric variables that act as drivers of cloud radiative effect, using Atmospheric Radiation Measurement (ARM) observations from the Eastern North Atlantic (ENA) site and the ARM Mobile Facility deployments at the Azores. We then establish causal networks based on these drivers and extract quantitative estimates of the causal pathways between aerosol, precipitation and cloud radiative effects.