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Improved representation of the global dust cycle using observational constraints on dust properties and abundance

Authors :
J. F. Kok
A. A. Adebiyi
S. Albani
Y. Balkanski
R. Checa-Garcia
M. Chin
P. R. Colarco
D. S. Hamilton
Y. Huang
A. Ito
M. Klose
D. M. Leung
L. Li
N. M. Mahowald
R. L. Miller
V. Obiso
C. Pérez García-Pando
A. Rocha-Lima
J. S. Wan
C. A. Whicker
Source :
Atmospheric Chemistry and Physics, Vol 21, Pp 8127-8167 (2021)
Publication Year :
2021
Publisher :
Copernicus Publications, 2021.

Abstract

Even though desert dust is the most abundant aerosol by mass in Earth's atmosphere, atmospheric models struggle to accurately represent its spatial and temporal distribution. These model errors are partially caused by fundamental difficulties in simulating dust emission in coarse-resolution models and in accurately representing dust microphysical properties. Here we mitigate these problems by developing a new methodology that yields an improved representation of the global dust cycle. We present an analytical framework that uses inverse modeling to integrate an ensemble of global model simulations with observational constraints on the dust size distribution, extinction efficiency, and regional dust aerosol optical depth. We then compare the inverse model results against independent measurements of dust surface concentration and deposition flux and find that errors are reduced by approximately a factor of 2 relative to current model simulations of the Northern Hemisphere dust cycle. The inverse model results show smaller improvements in the less dusty Southern Hemisphere, most likely because both the model simulations and the observational constraints used in the inverse model are less accurate. On a global basis, we find that the emission flux of dust with a geometric diameter up to 20 µm (PM20) is approximately 5000 Tg yr−1, which is greater than most models account for. This larger PM20 dust flux is needed to match observational constraints showing a large atmospheric loading of coarse dust. We obtain gridded datasets of dust emission, vertically integrated loading, dust aerosol optical depth, (surface) concentration, and wet and dry deposition fluxes that are resolved by season and particle size. As our results indicate that this dataset is more accurate than current model simulations and the MERRA-2 dust reanalysis product, it can be used to improve quantifications of dust impacts on the Earth system.

Subjects

Subjects :
Physics
QC1-999
Chemistry
QD1-999

Details

Language :
English
ISSN :
16807316 and 16807324
Volume :
21
Database :
Directory of Open Access Journals
Journal :
Atmospheric Chemistry and Physics
Publication Type :
Academic Journal
Accession number :
edsdoj.22f5d5cccc4d0ba2c75eebf68523f7
Document Type :
article
Full Text :
https://doi.org/10.5194/acp-21-8127-2021