globalchange  > 影响、适应和脆弱性
DOI: 10.5194/cp-14-1051-2018
Scopus记录号: 2-s2.0-85049945352
论文题名:
Rapid increase in simulated North Atlantic dust deposition due to fast change of northwest African landscape during the Holocene
作者: Egerer S.; Claussen M.; Reick C.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2018
卷: 14, 期:7
起始页码: 1051
结束页码: 1066
语种: 英语
Scopus关键词: climate modeling ; climate variation ; continental margin ; dust ; heterogeneity ; Holocene ; humid environment ; landscape change ; marine sediment ; spatiotemporal analysis ; vegetation dynamics ; Atlantic Ocean ; Atlantic Ocean (North) ; Sahara
英文摘要: Marine sediment records from a series of core sites along the northwest African margin show a sudden increase in North Atlantic dust deposition at about 5 ka BP that has been associated with an abrupt end of the African Humid Period (AHP). To assess the causes of the abrupt shift in North Atlantic dust deposition, we explore changes in the Holocene dust cycle and in North African climate and landscape by performing several time slice simulations from 8 ka BP until the preindustrial era. To do this, we use the coupled aerosol-climate model ECHAM6-HAM2 including dynamic vegetation and interactive dust, wherein ocean conditions and lake surface area are prescribed for each time slice.

We find a rapid increase in simulated dust deposition between 6 and 4 ka BP that is fairly consistent with the abrupt change in marine sediment records at around 20° N close to the northwest African margin. At more northern and more remote cores, a significant change in dust deposition is noticeable roughly between 6 and 2 ka BP in the simulations as well as in the records, but the change is less sharp compared to the near-margin core sites. The rapid change in simulated dust deposition is caused by a rapid increase in simulated dust emissions in the western Sahara, where the main dust sources for dust transport towards the North Atlantic are located. The sudden increase in dust emissions in the western Sahara is according to our simulations a consequence of a fast decline of vegetation cover from 22 to 18° N that might occur due to vegetation-climate feedbacks or due to the existence of a precipitation threshold on vegetation growth. Additionally, the prescribed gradual reduction of lake area enforces accelerated dust release as highly productive dust sources are uncovered. Concurrently with the continental drying, surface winds in the western Sahara are accelerated. Changes in the Saharan landscape and dust emissions south of 18° N and in the eastern Sahara play a minor role in driving the dynamics of North Atlantic dust deposition at the core sites. Our study identifies spatial and temporal heterogeneity in the transition of the North African landscape. As a consequence, implications from local data records on large-scale climate have to be treated with caution. © Author(s) 2018.

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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109545
Appears in Collections:影响、适应和脆弱性
气候变化事实与影响

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作者单位: Max Planck Institute for Meteorology, Bundesstraße 53, Hamburg, 20146, Germany; International Max Planck Research School on Earth System Modelling, Bundesstraße 53, Hamburg, 20146, Germany; Center for Earth System Research and Sustainability, Universität Hamburg, Bundesstraße 53, Hamburg, 20146, Germany

Recommended Citation:
Egerer S.,Claussen M.,Reick C.. Rapid increase in simulated North Atlantic dust deposition due to fast change of northwest African landscape during the Holocene[J]. Climate of the Past,2018-01-01,14(7)
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