Work

Sub-cloud aerosol intrusion and microphysical transition in boundary layer clouds revealed by integrated lidar system

Year: 2026

Type: article

Abstract: Aerosol–cloud interactions are strongly regulated within the narrow transition layer immediately below cloud base, where aerosol activation and boundary-layer restructuring occur. However, continuous observations in this critical altitude range are frequently hindered by geometric overlap effects and severe signal attenuation under optically thick clouds, limiting process-level diagnosis. Here we develop a blind-zone-free extinction retrieval framework that integrates side-scattering CCD measurements with vertically resolved lidar backscatter through a near-end constrained iterative calibration. The approach reconstructs continuous aerosol extinction profiles from the surface to cloud base even under strong cloud attenuation, and enables dual-wavelength lookup-table inversion of effective radius (Reff) and particle number concentration (N).,Application to a representative cloud evolution event reveals a clear transition from a decoupled boundary-layer structure—characterized by a persistent clean gap beneath cloud base—to a coupled regime associated with enhanced convection. During the recoupling phase, aerosol-rich air masses penetrate the cloud-base layer, accompanied by a rapid increase in N and a simultaneous decrease in Reff, consistent with intensified cloud condensation nuclei activation. ERA5 thermodynamic diagnostics further support the role of boundary-layer destabilization in facilitating vertical aerosol transport.,These results highlight the importance of resolving the cloud-base transition layer for identifying aerosol–cloud coupling pathways and provide observational evidence linking boundary-layer restructuring to microphysical cloud responses.

Source: Optics & Laser Technology

DOI: 10.1016/j.optlastec.2026.115760