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Simulating glacial dust changes in the Southern Hemisphere using ECHAM6.3-HAM2.3

Authors :
Stephan Krätschmer
Michèlle van der Does
Martin Werner
Gerrit Lohmann
Christoph Völker
Frank Lamy
Source :
Climate of the Past, Vol 18, Pp 67-87 (2022), EPIC3Climate of the Past, COPERNICUS GESELLSCHAFT MBH, 18(1), pp. 67-87, ISSN: 1814-9324
Publication Year :
2022
Publisher :
Copernicus Publications (EGU), 2022.

Abstract

Mineral dust aerosol constitutes an important component of the Earth’s climate system, not only on short timescales due to direct and indirect influences on the radiation budget, but also on long timescales by acting as a fertilizer for the biosphere and thus affecting the global carbon cycle. For a quantitative assessment of its impact on the global climate, state-of-the-art atmospheric and aerosol models can be utilized. In this study, we use the ECHAM6.3-HAM2.3 model to perform global simulations of the mineral dust cycle for present-day (PD), pre-industrial (PI) and Last Glacial Maximum (LGM) climate conditions. The intercomparison with marine sediment and ice core data as well as other modeling studies shows that the obtained annual dust emissions of 1221, 923 and 5159 Tg for PD, PI and LGM, respectively, generally agree well with previous findings. Our analyses focussing on the Southern Hemisphere suggest that over 90 % of the mineral dust deposited over Antarctica are of Australian or South American origin during both PI and LGM. However, contrary to previous studies, we find that Australia contributes a higher proportion during the LGM, which is mainly caused by changes in the precipitation patterns. Obtained increased particle radii during the LGM can be traced back to increased sulphate condensation on the particle surfaces as a consequence of longer particle lifetimes. The meridional transport of mineral dust from its source regions to the South Pole takes place at different altitudes, depending on the grain size of the dust particles. We find a trend of generally lower transport heights during the LGM compared to PI as a consequence of reduced convection due to colder surfaces, indicating a vertically less extensive Polar Cell.

Details

Language :
English
ISSN :
18149332
Database :
OpenAIRE
Journal :
Climate of the Past, Vol 18, Pp 67-87 (2022), EPIC3Climate of the Past, COPERNICUS GESELLSCHAFT MBH, 18(1), pp. 67-87, ISSN: 1814-9324
Accession number :
edsair.doi.dedup.....3e5929b2acdd5462349d940a0e5cd7b2
Full Text :
https://doi.org/10.5194/cp-18-67-2022