Understanding aerosol–cloud interactions in tropical anvil clouds with cloud-resolving simulations

Anvil clouds form when ice particles detrained from deep convective updrafts spread horizontally near the tropopause, covering areas far larger than their parent convective cores and thereby strongly influencing the tropical cloud radiative effect. Atmospheric aerosol particles can modify anvil cloud development through their impacts on cloud microphysical and macrophysical processes and associated latent and radiative heating. As a result, aerosol effects on anvil clouds may have important implications for Earth’s radiation budget and radiative forcing. However, quantifying aerosol effects on anvil clouds remains challenging due to limited understanding of the processes that control anvil cloud extent.

Here, we use a cloud-resolving System for Atmospheric Modeling (SAM) to investigate how aerosol perturbations affect anvil cloud evolution. A series of warm-bubble–triggered isolated convection simulations is performed to capture the full life cycle of anvil clouds. Aerosol perturbations are represented through prescribed cloud droplet number concentrations, following the RCEMIP aerosol–cloud interaction protocol (Dagan et al., 2025). To quantify anvil evolution, we apply a passive tracer diagnostic that approximates cloud age after detrainment, enabling the examination of cloud properties as a function of time since convective origin (Gasparini et al., 2025). Our results provide new insight into how aerosol pollution influences anvil cloud evolution, persistence, and associated radiative effects, with implications for representing aerosol–cloud–radiation interactions in climate models.