A simple yet accurate profile model for vertical aerosol extinction estimation over the China Seas

Accurate estimation of vertical aerosol extinction coefficient (AEC) profiles is essential for lidar retrievals and radiative transfer modeling, yet it remains challenging over marine regions due to complex structural variability. To address this, we developed an analytical two-layer AEC profile model for the China Seas (CS) using CALIPSO observations collocated with the ERA5 meteorological data (2007-2021). By applying height-resolved hierarchical clustering (HC) from 0.18 to 12 km, we identified two distinct vertical regimes: a well-mixed planetary boundary layer (PBL) and an overlying free-tropospheric layer (FTL). The model parameterizes the PBL AEC using a Gaussian function to capture turbulent mixing, while representing the FTL with an exponential decay function to characterize dilution processes. Optimized via a genetic algorithm (GA), the model exhibits excellent agreement with CALIPSO observations across the Bohai-Yellow Sea (BYS), the East China Sea (ECS), and the South China Sea (SCS), achieving R²>0.9 and RMSE<0.01km^-1. This physically grounded and computationally efficient approach provides a robust and accurate solution for marine AEC estimation.