Dust and Primary Biological Aerosol Particles (PBAP) Effects on Sea Breeze Systems Over Houston

Sea-breeze-induced convection plays a critical role in coastal weather but remains challenging to simulate due to complex aerosol-cloud interactions. Although mineral dust and primary biological aerosol particles (PBAPs) are known to act as cloud condensation nuclei and ice nucleating particles, their impacts on different convective cloud regimes and various cloud development stages are poorly understood. Here we examine the combined and individual impacts of dust and PBAPs on a representative convective case over Houston during the tracking aerosol convection interactions experiment campaign (17 June 2022) using WRF-Chem with explicit emissions and rupture processes of PBAPs, and aerosol-aware two-moment microphysics. The results show that dust and PBAPs generally reduce precipitation through decreases in rain production and ice-phase particle formation and growth, whereas ruptured PBAPs enhance liquid and ice water contents and increase precipitation efficiency. These microphysical responses become more evident with convective strength and are most pronounced in deep convection. Aerosol effects on convective development are expressed mainly through changes in the probability of moderate-to-deep transition, with dust and PBAPs increasing this transition and ruptured PBAPs reducing it. These findings suggest the stage-dependent impacts of natural aerosol on sea-breeze convection and underscore the importance of representing biological aerosol processes in weather and climate models.