TY - JOUR

T1 - Saltation-Induced Dust Emission of Dust Devils in the Convective Boundary Layer

T2 - An LES Study on the Meter Scale

AU - Klamt, J.

AU - Giersch, S.

AU - Raasch, S.

N1 - 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@Göttingen as part of the NHR infrastructure. Open access funding enabled and organized by Projekt DEAL.

PY - 2024/3/28

Y1 - 2024/3/28

N2 - 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.

AB - 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.

KW - convective boundary layer

KW - dust devils

KW - large-eddy simulation

KW - PALM model system

KW - regional dust emission

KW - saltation bombardment

UR - http://www.scopus.com/inward/record.url?scp=85189518107&partnerID=8YFLogxK

U2 - 10.1029/2023JD040058

DO - 10.1029/2023JD040058

M3 - Article

AN - SCOPUS:85189518107

VL - 129

JO - Journal of Geophysical Research: Atmospheres

JF - Journal of Geophysical Research: Atmospheres

SN - 2169-897X

IS - 7

M1 - e2023JD040058

ER -