Simulations of pollen in North American and their influence on climate

Pollen is one type of bioaerosol emitted in large quantities from many northern hemisphere vegetation types and has known impacts on human health and climate. A pollen emissions model accounting for 13 of the most prevalent types of pollen in North America is used to simulate emissions in the present day and the future and estimate concentrations with time.  Model simulations are evaluated with both ground-based pollen counts and remote sensing techniques to understand the seasonal timing of different pollen emission types and their relevance for climate.  Additionally, pollen grains can rupture and create smaller, subpollen particles that can influence cloud formation as cloud condensation nuclei and ice nucleating particles. Simulations indicate that the subpollen particles enhance cloud microphysical processes more than intact pollen grains by influencing the spatial extent and vertical structure of convective systems.  We evaluate the uncertainty of how estimated versus observed rupture rates and find that simulated SPP impacts are intensified when incorporating laboratory measured pollen rupture rates.