DOI: 10.1007/s00382-011-1255-2
Scopus记录号: 2-s2.0-84856273635
论文题名: The West African monsoon onset in 2006: Sensitivity to surface albedo, orography, SST and synoptic scale dry-air intrusions using WRF
作者: Flaounas E. ; Janicot S. ; Bastin S. ; Roca R.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2012
卷: 38, 期: 2017-03-04 起始页码: 685
结束页码: 708
语种: 英语
英文关键词: Dry-air intrusions
; West African monsoon onset
; WRF model
英文摘要: In order to test the sensitivity of the transitional phase of the 2006 West African monsoon (WAM) onset to different mechanisms, weather research and forecasting (WRF) model simulations have been carried out addressing the role of the Saharan heat low (SHL) and its sensitivity to the albedo field and to the northern Africa orography, and the role of the sea surface temperature (SST) in the eastern tropical Atlantic and Mediterranean. Lowering albedo over the desert region induces a northward location of the inter-tropical convergence zone (ITCZ), while removing mountains in North Africa reduces rainfall over West Africa. Shifting SST forward by 15 days leads to a northward location of the ITCZ before the WAM onset. However none of these factors modifies the timing of the WAM onset in 2006. The transitional phase of the 2006 WAM onset has been examined in more detail. The enhancement of SHL intensity, combined with the development of the oceanic cold tongue in the Guinea gulf, leads to low-level moisture flux divergence in the ITCZ reducing rainfall and increasing low-level humidity over the Sahel. However, weakening of convection can be clearly attributed to dry-air intrusions in mid-levels, originating from the subtropical westerly jet and associated with Rossby wave pattern over North Africa. Sensitivity tests on the synoptic scale forcing outside of the WRF model domain confirm the dominating role of large-scale dynamics to control the transitional phase of the WAM onset and its timing. However it is shown that the regional factors can modulate this larger scale forcing. © 2011 Springer-Verlag. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/55377
Appears in Collections: 过去全球变化的重建
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作者单位: LATMOS/IPSL, Université Pierre et Marie Curie (UPMC), Boite 102, 4 Place Jussieu, 75252 Paris cedex 05, France; LOCEAN/IPSL, IRD, UPMC, Paris, France; LATMOS/IPSL, CNRS, UPMC, Paris, France; LMD/IPSL, CNRS, UPMC, Paris, France
Recommended Citation:
Flaounas E.,Janicot S.,Bastin S.,et al. The West African monsoon onset in 2006: Sensitivity to surface albedo, orography, SST and synoptic scale dry-air intrusions using WRF[J]. Climate Dynamics,2012-01-01,38(2017-03-04)