Does the size distribution of mineral dust aerosols depend on the wind speed at emission?

TL;DR

This study investigates whether the size distribution of mineral dust aerosols depends on wind speed at emission, finding it to be independent, which simplifies modeling and interpretation of dust-related processes.

Contribution

It provides empirical evidence that dust size distribution is independent of wind speed, supporting the brittle fragmentation theory over other models.

Findings

Dust size distribution is independent of wind speed.

Brittle fragmentation theory aligns with observed data.

Simplifies dust emission modeling in climate studies.

Abstract

The size distribution of mineral dust aerosols partially determines their interactions with clouds, radiation, ecosystems, and other components of the Earth system. Several theoretical models predict that the dust size distribution depends on the wind speed at emission, with larger wind speeds predicted to produce smaller aerosols. The present study investigates this prediction using a compilation of published measurements of the size-resolved vertical dust flux emitted by eroding soils. Surprisingly, these measurements indicate that the size distribution of naturally emitted dust aerosols is independent of the wind speed. The recently formulated brittle fragmentation theory of dust emission is consistent with this finding, whereas other theoretical dust emission models are not. The independence of the emitted dust size distribution with wind speed simplifies both the interpretation of geological records of dust deposition and the parameterization of dust emission in atmospheric circulation models.