Seasonal provenance changes in present-day Saharan dust collected in and off Mauritania
Seasonal provenance changes in present-day Saharan dust collected in and off Mauritania
复制标题
毛里塔尼亚内外收集的当今撒哈拉沙尘的季节性来源变化
DOI：
10.5194/acp-17-10163-2017
复制
发表时间：
2017
影响因子：
6.3
通讯作者：
J. Stuut
中科院分区：
文献类型：
--
作者：
Carmen A. Friese;J. V. Hateren;C. Vogt;G. Fischer;J. Stuut
摘要。撒哈拉沙尘对地球气候系统具有至关重要的影响，其排放、运输和沉积与风速、降水、温度和植被覆盖等密切相关。由于环境变化而导致的撒哈拉沙尘物理和化学性质的变化经常被用来重建过去的气候。然而，为了更好地解释可能的气候变化，需要了解粉尘源区域。通过分析输送或沉积粉尘的矿物学成分，可以推断潜在的粉尘源区域。西北非洲的夏季沙尘运输发生在撒哈拉空气层（SAL）。在大陆沙尘源区，沙尘也在SAL中输送；然而，主要的沙尘输入来自附近的低空信风沙尘源。因此，源区和相关的矿物学示踪剂随季节和采样地点而异。为了验证这一点，研究人员分析了2013年至2015年间毛里塔尼亚海岸和海洋沉积物捕集器中收集的粉尘。对气象资料、粒径分布、反轨迹和矿物学分析进行了比较，得出了粉尘的来源和扩散。对于陆上沙尘样本，其来源区域随信风方向的季节变化而变化。夏季，三边石和白云石可能来自西撒哈拉和当地；冬季，绿泥石、蛇纹石和金红石可能来自毛里塔尼亚和马里。相比之下，对于近海采集的样品，粉尘源根据粉尘输送空气层的季节变化而变化。在夏季，沙尘从毛里塔尼亚、马里和利比亚运入沙尘区。在冬季，沙尘随贸易船从西撒哈拉运来，如氟飞石等。
Abstract. Saharan dust has a crucial influence on the earth climate system and its emission, transport and deposition are intimately related to, e.g., wind speed, precipitation, temperature and vegetation cover. The alteration in the physical and chemical properties of Saharan dust due to environmental changes is often used to reconstruct the climate of the past. However, to better interpret possible climate changes the dust source regions need to be known. By analysing the mineralogical composition of transported or deposited dust, potential dust source areas can be inferred. Summer dust transport off northwest Africa occurs in the Saharan air layer (SAL). In continental dust source areas, dust is also transported in the SAL; however, the predominant dust input occurs from nearby dust sources with the low-level trade winds. Hence, the source regions and related mineralogical tracers differ with season and sampling location. To test this, dust collected in traps onshore and in oceanic sediment traps off Mauritania during 2013 to 2015 was analysed. Meteorological data, particle-size distributions, back-trajectory and mineralogical analyses were compared to derive the dust provenance and dispersal. For the onshore dust samples, the source regions varied according to the seasonal changes in trade-wind direction. Gibbsite and dolomite indicated a Western Saharan and local source during summer, while chlorite, serpentine and rutile indicated a source in Mauritania and Mali during winter. In contrast, for the samples that were collected offshore, dust sources varied according to the seasonal change in the dust transporting air layer. In summer, dust was transported in the SAL from Mauritania, Mali and Libya as indicated by ferroglaucophane and zeolite. In winter, dust was transported with the trades from Western Sahara as indicated by, e.g., fluellite.
影响因子：
4.5
作者：
H. Ploug;M. Iversen;G. Fischer
通讯作者：
H. Ploug;M. Iversen;G. Fischer
影响因子：
4.9
作者：
Iversen, M. H.;Ploug, H.
通讯作者：
Ploug, H.
影响因子：
4.9
作者：
Fischer, Gerhard;Romero, Oscar;Wefer, Gerold
通讯作者：
Wefer, Gerold