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

An LES Study on the Meter Scale

authored by: 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.
Organisation(s): Institute of Meteorology and Climatology
External Organisation(s): German Aerospace Center (DLR)
Type: Article
Journal: Journal of Geophysical Research: Atmospheres
Volume: 129
No. of pages: 28
ISSN: 2169-897X
Publication date: 28.03.2024
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Geophysics, Atmospheric Science, Space and Planetary Science, Earth and Planetary Sciences (miscellaneous)
Sustainable Development Goals: SDG 13 - Climate Action
Electronic version(s): https://doi.org/10.1029/2023JD040058 (Access: Open)

BibTeX

@article{90d4c6075d4c41b3aa59d2316324dd2d,
title = "Saltation-Induced Dust Emission of Dust Devils in the Convective Boundary Layer: An LES Study on the Meter Scale",
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.",
keywords = "convective boundary layer, dust devils, large-eddy simulation, PALM model system, regional dust emission, saltation bombardment",
author = "J. Klamt and S. Giersch and S. Raasch",
note = "Funding Information: The work by Sebastian Giersch was partly funded by the German Research Foundation (DFG) under Grant RA 617/31-1. In addition, all authors supported the work as part of their employment at the Leibniz University Hannover. The authors gratefully acknowledge the computing time granted by the Resource Allocation Board and provided on the supercomputers Lise and Emmy at NHR@ZIB and NHR@G{\"o}ttingen as part of the NHR infrastructure. Open access funding enabled and organized by Projekt DEAL.",
year = "2024",
month = mar,
day = "28",
doi = "10.1029/2023JD040058",
language = "English",
volume = "129",
journal = "Journal of Geophysical Research: Atmospheres",
issn = "2169-897X",
publisher = "Wiley-Blackwell",
number = "7",
}