Comments on the origin of dust in East Antarctica for present and ice age conditions
Comments on the origin of dust in East Antarctica for present and ice age conditions
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关于当前和冰河时代条件下东南极洲尘埃起源的评论
DOI：
10.1007/bf00115229
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
V. Petrov
中科院分区：
文献类型：
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作者：
A. Gaudichel;M. Angelis;S. Joussaume;J. Petit;Y. Korotkevitch;V. Petrov
我们研究了从对应于当前和末次盛冰期 (LGM) 气候条件的四个南极冰样本中提取的 327 个粘土矿物颗粒的分布。所有样品中均鉴定出伊利石、绿泥石、蒙皂石和高岭石。重点关注高岭石，因为它可能被用作低纬度土壤的示踪剂，我们发现末次盛冰期样品的含量显着减少，而末次盛冰期雪中的灰尘浓度比当前气候条件高约 30 倍。这可以解释为澳大利亚来源对气候的贡献发生了变化。第二种方法是基于在当今和冰河时代条件下使用大气环流模型（AGCM）对沙漠尘埃循环进行建模。与矿物学结果不同，该模型表明，在当今和末次盛冰期气候条件下，东南极洲沉积物中澳大利亚尘埃源的普遍存在。然而，该模型未能重现末次盛冰期期间灰尘沉积物的强劲增加。这种差异可能部分是由于模型中缺乏更高纬度的尘埃源。末次盛冰期冰芯中记录的更强的尘埃输入可能与额外的活跃高纬度源（可能靠近南美洲）与来自低纬度地区的大气背景重叠有关。
We have studied the distribution of 327 clay mineral particles retrieved from four Antaretic ice smaples corresponding to present and Last Glacial Maximum (LGM) climate conditions. Illite, chlorite, smectite and kaolinite were identified in all samples. Focusing on kaolinite, because of its use as a possible tracer of low latitude soils, we find a significantly smaller amount for LGM samples while the dust concentration in snow during the LGM was about 30 times higher than for present climate conditions. This can be interpreted as change in the contribution of the Australian source with climate.A second approach was based on the modeling of the desert dust cycle using an Atmospheric General Circulation Model (AGCM) under both present-day and ice age conditions. Unlike mineralogical results, the model suggests the prevalence of the Australian dust source in the deposits over East Antarctica under both present-day and LGM climate conditions. However the model fails to reproduce the strong increase in dust deposits during the LGM. This discrepancy could be partly due to the lack of a higher latitude dust source in the model.The stronger dust input recorded in ice cores for the LGM could be related to an additional active high latitude source (possibly close to South America) overlapping the atmospheric background coming from low latitude areas.