DOI: 10.1002/jgrd.503632013
论文题名: The contribution of African easterly waves to monsoon precipitation in the CMIP3 ensemble
作者: Skinner C.B. ; Diffenbaugh N.S.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 9 起始页码: 3590
结束页码: 3609
语种: 英语
Scopus关键词: Global warming
; Greenhouse effect
; Greenhouses
; Rain
; Uncertainty analysis
; African easterly jet
; African easterly waves
; Convective parameterization
; Coupled Model Intercomparison Project
; General circulation model
; Monsoon precipitation
; Precipitation variability
; Seasonal precipitations
; Climate models
; atmospheric forcing
; general circulation model
; global warming
; monsoon
; numerical model
; precipitation (climatology)
; precipitation assessment
; precipitation intensity
; twentieth century
; West Africa
英文摘要: African easterly waves (AEWs) are a major source of synoptic-scale rainfall variability throughout West Africa. Given the persistent uncertainty in the response of precipitation over West Africa to enhanced greenhouse forcing, we analyze the contribution of AEWs to the simulation of precipitation over West Africa in the Coupled Model Intercomparison Project Phase 3 (CMIP3) ensemble of general circulation models. Nearly all models that simulate weaker-than-observed AEW activity exhibit a lack of coupling between AEWs and precipitation. Only those models that employ a convective parameterization with a moisture convergence-based closure or trigger, or a prognostic closure with a convective suppression scheme, demonstrate a consistent connection between AEWs and precipitation. The strength of simulated AEW activity is largely dependent on the simulated magnitude and positioning of the African easterly jet and low-level westerlies. We find a strong positive relationship between the magnitude of simulated AEW activity and seasonaland synoptic-scale precipitation. Models with weaker-than-observed AEW activity exhibit a disproportionately low percentage of precipitation variability at AEW timescales. Conversely, in those models that simulate stronger-than-observed AEW activity, dynamical forcing associated with the wave tends to produce overly intense individual precipitation events. Our results suggest that the simulation of AEWs contributes substantially to the spread in mean seasonal precipitation across the CMIP3 ensemble during the 20th century, and that improved understanding of the effect of enhanced greenhouse forcing on the relationship between AEWs and precipitation could help to narrow the uncertainty in the response of West African rainfall to continued global warming. © 2013. American Geophysical Union. All Rights Reserved. 资助项目: 955283
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63435
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Department of Environmental Earth System Science, Stanford University, 473 Via Ortega, Stanford, CA 94301, United States; Woods Institute for the Environment, Stanford University, Stanford, CA, United States
Recommended Citation:
Skinner C.B.,Diffenbaugh N.S.. The contribution of African easterly waves to monsoon precipitation in the CMIP3 ensemble[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(9)