干旱区生态环境知识资源中心(Arid): The end of the African humid period as seen by a transient comprehensive Earth system model simulation of the last 8000 years

Arid

DOI	10.5194/cp-16-117-2020
	The end of the African humid period as seen by a transient comprehensive Earth system model simulation of the last 8000 years
	Dallmeyer, Anne 1; Claussen, Martin 1,2; Lorenz, Stephan J.3; Shanahan, Timothy 4
通讯作者	Dallmeyer, Anne
来源期刊	CLIMATE OF THE PAST
ISSN	1814-9324
EISSN	1814-9332
出版年	2020
卷号	16 期号:1 页码:117-140
英文摘要	Enhanced summer insolation during the early and mid-Holocene drove increased precipitation and widespread expansion of vegetation across the Sahara during the African humid period (AHP). While changes in atmospheric dynamics during this time have been a major focus of palaeoclimate modelling efforts, the transient nature of the shift back to the modern desert state at the end of this period is less well understood. Reconstructions reveal a spatially and temporally complex end of the AHP, with an earlier end in the north than in the south and in the east than in the west. Some records suggest a rather abrupt end, whereas others indicate a gradual decline in moisture availability. Here we investigate the end of the AHP based on a transient simulation of the last 7850 years with the comprehensive Earth system model MPI-ESM1.2. The model largely reproduces the time-transgressive end of the AHP evident in proxy data, and it indicates that it is due to the regionally varying dynamical controls on precipitation. The impact of the main rain-bringing systems, i.e. the summer monsoon and extratropical troughs, varies spatially, leading to heterogeneous seasonal rainfall cycles that impose regionally different responses to the Holocene insolation decrease. An increase in extratropical troughs that interact with the tropical mean flow and transport moisture to the western Sahara during the mid-Holocene delays the end of the AHP in that region. Along the coast, this interaction maintains humid conditions for a longer time than further inland. Drying in this area occurs when this interaction becomes too weak to sustain precipitation. In the lower latitudes of west Africa, where the rainfall is only influenced by the summer monsoon dynamics, the end of the AHP coincides with the retreat of the monsoonal rain belt. The model results clearly demonstrate that non-monsoonal dynamics can also play an important role in forming the precipitation signal and should therefore not be neglected in analyses of north African rainfall trends.
类型	Article
语种	英语
国家	Germany ; USA
开放获取类型	gold, Green Submitted, Green Accepted
收录类别	SCI-E
WOS记录号	WOS:000508129600001
WOS关键词	INTERACTIONS CAUSING PRECIPITATION ; NORTHERN AFRICA ; MONSOON CHANGES ; EASTERLY JET ; ORBITAL PARAMETERS ; ARABIAN PENINSULA ; TROPICAL PLUMES ; DUST DEPOSITION ; GLACIAL MAXIMUM ; SUMMER MONSOON
WOS类目	Geosciences, Multidisciplinary ; Meteorology & Atmospheric Sciences
WOS研究方向	Geology ; Meteorology & Atmospheric Sciences
EI主题词	2020-01-15
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/312478
作者单位	1.Max Planck Inst Meteorol, Land Earth Syst, Bundesstr 53, D-20146 Hamburg, Germany; 2.Univ Hamburg, CEN, Meteorol Inst, Bundesstr 55, D-20146 Hamburg, Germany; 3.Max Planck Inst Meteorol, Ocean Earth Syst, Bundesstr 53, D-20146 Hamburg, Germany; 4.Univ Texas Austin, Dept Geol Sci, 1 Univ Stn C9000, Austin, TX 78712 USA
推荐引用方式 GB/T 7714	Dallmeyer, Anne,Claussen, Martin,Lorenz, Stephan J.,et al. The end of the African humid period as seen by a transient comprehensive Earth system model simulation of the last 8000 years[J],2020,16(1):117-140.
APA	Dallmeyer, Anne,Claussen, Martin,Lorenz, Stephan J.,&Shanahan, Timothy.(2020).The end of the African humid period as seen by a transient comprehensive Earth system model simulation of the last 8000 years.CLIMATE OF THE PAST,16(1),117-140.
MLA	Dallmeyer, Anne,et al."The end of the African humid period as seen by a transient comprehensive Earth system model simulation of the last 8000 years".CLIMATE OF THE PAST 16.1(2020):117-140.