Saltation-Induced Dust Emission of Dust Devils in the Convective Boundary Layer

An LES Study on the Meter Scale

verfasst von

J. Klamt, S. Giersch, S. Raasch

Abstract

Dust devils are vertically oriented, columnar vortices that form within the atmospheric convective boundary layer (CBL) of dry regions. They are able to lift a sufficient amount of soil particles including dust to become visible and are considered as a potentially important dust source for the atmosphere. Mineral dust, a key component of atmospheric aerosols, influences the climate by affecting the radiation budget and cloud formation. Current estimates of the contribution of dust devils to the global, regional, and local dust release vary considerably from less than 1% to more than 50%. To address this uncertainty, we perform the highest resolved large-eddy simulation (LES) study on dust emission in the CBL to date, using the PALM model system and the saltation-based Air Force Weather Agency (AFWA) dust emission scheme. Our results show that under desert-like conditions, dust devils are responsible for an average of 5% of regional dust emissions, with temporary maxima of up to 15%. This contrasts with previous measurement-based (>35%) and LES-based estimates (∼0.1%). Local emissions of dust devils (up to 10 mg m⁻² s⁻¹) are 1–3 orders of magnitude higher than the emission in the surroundings. This makes dust devils important for air quality and visibility. Additionally, our study reveals previously unknown large-scale convective dust emission patterns. These patterns are tied to the CBL's cellular flow structure and are the main cause of dust release. Contrary to other studies, our findings clarify the important role of saltation-induced dust emission.

Organisationseinheit(en)

Institut für Meteorologie und Klimatologie

Externe Organisation(en)

Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)

Typ

Artikel

Journal

Journal of Geophysical Research: Atmospheres

Band

129

Anzahl der Seiten

28

ISSN

2169-897X

Publikationsdatum

28.03.2024

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Geophysik, Atmosphärenwissenschaften, Astronomie und Planetologie, Erdkunde und Planetologie (sonstige)

Ziele für nachhaltige Entwicklung

SDG 13 – Klimaschutzmaßnahmen

Elektronische Version(en)

https://doi.org/10.1029/2023JD040058 (Zugang: Offen)