Modeling Size Dust Particle Size Distribution

Aircraft measurements have found surprisingly large concentrations of super coarse atmospheric dust (diameter > 10 um), which accounts for approximately a quarter of particulate matter mass in the atmosphere. However, current atmospheric models are unable to reproduce this abundance of super coarse dust. In this work, we develop a parameterization for the emission of super coarse dust. We evaluate this new parameterization in the Community Earth System Model (CESM) and find that it enables the model to reproduce in situ aircraft measurements of super coarse atmospheric dust near dust source regions. However, the model still underestimates super coarse atmospheric dust over dust outflow regions, possibly due to errors in deposition processes. 

Considering that it is now well accepted that models greatly underestimate super coarse dust, we anticipate that the new parameterization developed in this work will be implemented in a wide range of atmospheric models. This would for example benefit investigations of the effects of coarse dust on climate, the hydrological cycle, and biogeochemistry.

For more information, read our publication on Geophysical Research Letters.