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.

中文翻译：

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使用 ECHAM6.3-HAM2.3 模拟南半球的冰川尘埃变化

摘要。矿物粉尘气溶胶是地球气候系统的重要组成部分，不仅在短期内直接和间接影响辐射收支，而且在长期内作为生物圈的肥料，从而影响全球碳循环。为了定量评估其对全球气候的影响，可以利用最先进的大气和气溶胶模型。在本研究中，我们使用 ECHAM6.3-HAM2.3 模型对当今 (PD)、前工业化 (PI) 和末次冰期最大值 (LGM) 气候条件下的矿物粉尘循环进行全球模拟。与海洋沉积物和冰芯数据的比对以及其他建模研究表明，获得的 PD、PI 和 LGM 的年粉尘排放量分别为 1221、923 和 5159 Tg，大体上同意先前的发现。我们针对南半球的分析表明，在 PI 和 LGM 期间，沉积在南极洲上空的矿物粉尘 90% 以上来自澳大利亚或南美。然而，与之前的研究相反，我们发现澳大利亚在 LGM 期间的贡献率更高，这主要是由降水模式的变化引起的。在 LGM 期间获得的增加的粒子半径可以追溯到由于更长的粒子寿命导致粒子表面硫酸盐凝结增加。矿物尘埃从源区到南极的经向传输发生在不同的高度，这取决于尘埃颗粒的粒度。