AUTHORS:

Florczyk, G., Witek M., Markowicz K.M.

ABSTRACT:

Understanding the interactions between atmospheric aerosols and the evolution of the planetary boundary layer (PBL) is important for human health, climate, and weather forecasting models. In this study, an eddydiffusivity mass-flux (EDMF) model is coupled with a radiative transfer model (RTM) to investigate the effects of aerosol optical depth τλ and single scattering albedo ω on the growth and thermodynamics of the PBL, or the so-called aerosol-PBL interactions (API). The developed model, called EDMF-AERO, was first extensively validated against in-situ radiosonde and microwave radiometer (MWR) observations in the summer, showing very good performance and enabling us to study the API effects proposed in the literature called stove and dome. Having established the model’s satisfactory accuracy we performed a sensitivity study, isolated API effects study, and estimated which compound effect of API influences PBL development more. For the stove case for τ500 = 0.4 and ω = 0.9,  the PBL growth speeds up ∼8% and warms up ∼12.5% faster compared to the reference (τ500 = 0, ω = 1). For the dome case for τ500 = 0.4 and ω = 0.9, the PBL growth slows down ∼5% and warms up ∼4.5% slower compared to the reference. In extreme conditions (τ500 = 1.5, ω = 0.81) for the stove case we recorded ∼62% and ∼72% increase in PBL growth and heating rates respectively. For the dome case, we recorded ∼21% and ∼22% decreases in PBL growth and heating rates respectively. In both cases, the feedback loop severely impacts surface aerosol concentrations and enhances heat index. Based on the sensitivity runs, a parametrization relating the τ500 and ω on the PBL heating rate and PBL growth is suggested. The EDMF-AERO model developed in this study proves to be capable of providing new insights into the topic of API.

Atmospheric Environment, 2025, vol. 352, art. 121192, doi: 10.1016/j.atmosenv.2025.121192