Three distinct scales dominate the role of eolian electric fields in dust turbulent transport

Abstract

Although previous studies have shown that eolian electric fields significantly alter the lifting and dynamics of dust particles, they are limited to mean fields. The effects of eolian electric fields on the dust turbulent transport have not been reported before. Here, by combing the observational data and wavelet-based spectral analysis, we find that eolian electric fields enhance the vertical turbulent transport of dust particles in the near-surface layer and exhibit three distinct crucial scales. Specifically, the eolian electric fields exhibit a dominant promoting effect at the kilometer-sized synoptic scale, a secondary suppressive effect at the hectometer-sized very-large-scale motion scale, and a negligible effect at the decameter-sized turbulent integral scale. Such scale-dependent electrical effects can be explained by the fact that the linear coupling between vertical eolian electric field and dust concentration is strongest at the synoptic scale, followed by the very-large-scale motion scale, and is weakest at the turbulent integral scale.