DOI: 10.1007/s00382-014-2260-z
Scopus记录号: 2-s2.0-84934908376
论文题名: Response of the North African summer monsoon to precession and obliquity forcings in the EC-Earth GCM
作者: Bosmans J.H.C. ; Drijfhout S.S. ; Tuenter E. ; Hilgen F.J. ; Lourens L.J.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2014
卷: 44, 期: 2017-01-02 起始页码: 279
结束页码: 297
语种: 英语
英文关键词: Astronomical forcing
; Milankovitch cycles
; North African monsoon
; Paleoclimate modelling
英文摘要: We investigate, for the first time, the response of the North African summer monsoon to separate precession and obliquity forcings using a high-resolution state-of-the-art coupled general circulation model, EC-Earth. Our aim is to better understand the mechanisms underlying the astronomical forcing of this low-latitude climate system in detail. The North African monsoon is strengthened when northern hemisphere summer insolation is higher, as is the case in the minimum precession and maximum obliquity experiments. In these experiments, the low surface pressure areas over the Sahara are intensified and located farther north, and the meridional pressure gradient is further enhanced by a stronger South Atlantic high pressure area. As a result, the southwesterly monsoon winds are stronger and bring more moisture into the monsoon region from both the northern and southern tropical Atlantic. The monsoon winds, precipitation and convection also extend farther north into North Africa. The precession-induced changes are much larger than those induced by obliquity, but the latter are remarkable because obliquity-induced changes in summer insolation over the tropics are nearly zero. Our results provide a different explanation than previously proposed for mechanisms underlying the precession- and, especially, obliquity-related signals in paleoclimate proxy records of the North African monsoon. The EC-Earth experiments reveal that, instead of higher latitude mechanisms, increased moisture transport from both the northern and southern tropical Atlantic is responsible for the precession and obliquity signals in the North African monsoon. This increased moisture transport results from both increased insolation and an increased tropical insolation gradient. © 2014, Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54541
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Earth Sciences, Utrecht University, Budapestlaan 4, Utrecht, Netherlands; Global Climate, Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, De Bilt, Netherlands; Department of Physical Geography, Utrecht University, Heidelberglaan 2, Utrecht, Netherlands; Royal Netherlands Meteorological Institute (KNMI), P.O. box 201, De Bilt, Netherlands; National Oceanographic Centre, European Way, Southampton, United Kingdom
Recommended Citation:
Bosmans J.H.C.,Drijfhout S.S.,Tuenter E.,et al. Response of the North African summer monsoon to precession and obliquity forcings in the EC-Earth GCM[J]. Climate Dynamics,2014-01-01,44(2017-01-02)