DOI: 10.1175/JCLI-D-15-0875.1
Scopus记录号: 2-s2.0-84996605259
论文题名: The diurnal cycle of warm season rainfall over West Africa. Part II: Convection-permitting simulations
作者: Zhang G. ; Cook K.H. ; Vizy E.K.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2016
卷: 29, 期: 23 起始页码: 8439
结束页码: 8454
语种: 英语
Scopus关键词: Boundary layers
; Climate models
; Heat convection
; Precipitation (chemical)
; Precipitation (meteorology)
; Climate variability
; Diurnal effects
; Numerical analysis/modeling
; Planetary boundary layers
; Regional climate modeling
; Seasonal mean rainfall
; Simulated rainfall
; Warm season rainfall
; Rain
英文摘要: Convection-permitting simulations at 3-km resolution using a regional climate model are analyzed to improve the understanding of the diurnal cycle of rainfall over West Africa and its underlying physical processes. The warm season of 2006 is used for the model simulations. The model produces an accurate representation of the observed seasonal mean rainfall and lower-troposphere circulation and captures the observed westward propagation of rainfall systems. Most of West Africa has a single diurnal peak of rainfall in the simulations, either in the afternoon or at night, in agreement with observations. However, the number of simulated rainfall systems is greater than observed in association with an overestimation of the initiation of afternoon rainfall over topography. The longevity of the simulated propagating systems is about 30% shorter than is observed, and their propagation speed is nearly 20% faster. The model captures the observed afternoon rainfall peaks associated with elevated topography (e.g., the Jos Plateau). Nocturnal rainfall peaks downstream of the topographic afternoon rainfall are also well simulated. However, these nocturnal rainfall peaks are too widespread, and the model fails to reproduce the observed afternoon rainfall peaks over regions removed from topographic influence. This deficiency is related to a planetary boundary layer that is deeper than observed, elevating unstable profiles and inhibiting afternoon convection. This study concludes that increasing model resolution to convection-permitting space scales significantly improves the diurnal cycle of rainfall compared with the models that parameterize convection, but this is not sufficient to fully resolve the issue, perhaps because other parameterizations remain. © 2016 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/50242
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, United States; Department of Geology and Geophysics, Yale University, New Haven, CT, United States
Recommended Citation:
Zhang G.,Cook K.H.,Vizy E.K.. The diurnal cycle of warm season rainfall over West Africa. Part II: Convection-permitting simulations[J]. Journal of Climate,2016-01-01,29(23)