SCG-DUSTIEAIM

Super-Coarse and Giant DUSTIEAIM

1 June 2026 - 30 September 2026

Lead Scientist: Evan Amato

Observatory: AMF (ARM Mobile Facility 1)

The SCG (Super Coarse and Giant) DUSTIEAIM guest instrument deployment will investigate the settling velocity of super-coarse (diameters >10 µm) and giant (>63 µm) dust particles during dust outbreaks observed as part of the DUSTIEAIM field campaign. Recent observations suggest that large dust particles are more abundant and persist longer in the atmosphere than predicted by theory and models, yet the physical processes controlling their vertical transport and gravitational settling remain poorly constrained by observations. This project will address this gap by directly measuring the size-resolved vertical structure of super-coarse and giant particles during dust storm events impacting the DUSTIEAIM field site. When combined with measurements of the vertical structure of the atmosphere and aerosol properties, these observations can be leveraged to retrieve size-resolved dust settling velocities for particles in the approximately 0.3–80 µm size range.

Observationally constrained measurements of the settling velocities of super-coarse and giant dust particles will improve our ability to model these large particles by improving the representation of their vertical and horizontal transport and by improving calculations of deposition velocity, which at the super-coarse and giant particle sizes is dominated by gravitational settling. A growing body of work indicates that large dust particles play an important role in nutrient transport and surface chemistry and exert a substantial warming influence on climate. By helping explain how these particles travel long distances despite their size—often referred to as the “giant dust particle conundrum”—this work will improve understanding of dust impacts on the Earth system.