An Eulerian-Lagrangian Model to Simulate Sea Spray Transport in the Marine Atmospheric Boundary Layer

Large-eddy simulations (LES) from the NCAR Turbulence with Particles (NTLP) model are used to simulate the spray-laden marine atmospheric boundary layer (MABL). We prescribe multiple different sea-spray generation functions (SSGF) which create Lagrangian point particles of various sizes at the ocean surface, and track them through the domain as their position, temperature, and radius evolve according to the resolved velocity, temperature, and humidity fields of the LES. By representing aerosols in a Lagrangian framework, unique statistics of sea spray and aerosol fate can be explored, such as change in size distributions due to evaporation, temperature adjustment to the local fluid, or the importance of two-way coupling. Using NTLP, we compare vertical concentration profiles of aerosols of multiple sizes with field experiments to validate our model. After validation, we explore the different processes that affect the temporal and spatial patterns of the size-resolved vertical aerosol profiles to gauge the importance of environmental conditions, namely atmospheric stability, wind speed, and sea surface temperature. In addition, since there exist many orders of magnitude of difference in proposed SSGFs due to the differences in experimental field conditions and limitations of measurement techniques, we explore a range of SSGFs to infer which of those are most appropriate for given conditions. Further, this study will discuss particle trajectories and probability density functions of residence times to infer the importance of two-way coupling.