Dust deposition in Antarctica in glacial and interglacial climate conditions: a modelling study


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dmitry.sein [ at ] awi.de

Abstract

The mineral dust cycle responds to climate variations and plays an important role in the climate system by affecting the radiative balance of the atmosphere and modifying biogeochemistry. Polar ice cores provide a unique information about deposition of aeolian dust particles transported over long distance. These cores are a paleoclimate proxy archive of climate variability thousands of years ago. The current study is a first attempt to simulate past interglacial dust cycles with a global aerosol-climate model ECHAM5-HAM. The results are used to explain the dust deposition changes in Antarctica in terms of quantitative contribution of different processes, such as emission, atmospheric transport and precipitation, which will help to interpret paleodata from Antarctic ice cores. The investigated periods include four interglacial time-slices such as the pre-industrial control (CTRL), mid-Holocene (6000 yr BP), last glacial inception (115 000 yr BP) and Eemian (126 000 yr BP). One glacial time interval, which is Last Glacial Maximum (LGM) (21 000 yr BP) was simulated as well as to be a reference test for the model. Results suggest an increase of mineral dust deposition globally, and in Antarctica, in the past interglacial periods relative to the pre-industrial CTRL simulation. Approximately two thirds of the increase in the mid-Holocene and Eemian is attributed to enhanced Southern Hemisphere dust emissions. Slightly strengthened transport efficiency causes the remaining one third of the increase in dust deposition. The moderate change of dust deposition in Antarctica in the last glacial inception period is caused by the slightly stronger poleward atmospheric transport efficiency compared to the pre-industrial. Maximum dust deposition in Antarctica was simulated for the glacial period. LGM dust deposition in Antarctica is substantially increased due to 2.6 times higher Southern Hemisphere dust emissions, two times stronger atmospheric transport towards Antarctica, and 30% weaker precipitation over the Southern Ocean. The model is able to reproduce the order of magnitude of dust deposition globally and in Antarctica for the pre-industrial and LGM climates.



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Published
Eprint ID
37325
DOI 10.5194/cpd-10-3715-2014

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Sudarchikova, N. , Mikolajewicz, U. , Timmreck, C. , O'Donnell, D. , Schurgers, G. , Sein, D. and Zhang, K. (2014): Dust deposition in Antarctica in glacial and interglacial climate conditions: a modelling study , Climate of the Past, 10 (5), pp. 3715-3753 . doi: 10.5194/cpd-10-3715-2014


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