| 14 Nov 2025
Exploring the processes of liquid water path sensitivity to aerosol-cloud interactions using output from a high-resolution large-eddy simulation
Abstract. Diagnostics from high-resolution Large-Eddy Simulations (LES) are used to investigate aerosol impacts on the liquid water path (LWP) sensitivity in a non-precipitating, single-layer liquid cloud regime. In two LES simulations, the 2013 conditions represent a low aerosol scenario, while the 1985 conditions represent a high aerosol scenario. Joint histograms of cloud droplet number concentration (Nd) and LWP reveal a non-linear relationship, with positive LWP sensitivity (increasing LWP with Nd) at low Nd and negative sensitivity at high Nd. The transition from positive to negative LWP sensitivity occurs at higher Nd values in the 1985 simulation (≈ 300 cm−3) compared to the 2013 simulation (≈ 100 cm−3), indicating that enhanced aerosol loading shifts the transition point. This shift reflects stronger droplet activation and sustained LWP growth under high CCN conditions. Diagnostics of the cloud dilution ratio indicate that negative LWP sensitivity is linked to enhanced cloud-top entrainment. The temporal evolution of the Nd–LWP relationship confirms increasing dominance of negative sensitivity in the 2013 case, while the 1985 case exhibits weaker LWP depletion. Additionally, aerosol perturbations also influence thermodynamic properties such as the apparent heating/cooling (Q1) and the moisture sink (Q2). Specifically, stronger cloud-top heating and moisture sinks are simulated during negative LWP sensitivity phases, particularly for high Nd in 2013, consistent with enhanced evaporation and entrainment. Aerosol perturbations thus modulate both microphysical and thermodynamic processes, producing distinct LWP sensitivity regimes with important implications for understanding aerosol–cloud–climate interactions.
Competing interests: I declare that neither I nor my co-authors have any competing interests.
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