DOI: 10.1175/JCLI-D-13-00449.1
Scopus记录号: 2-s2.0-84901838322
论文题名: Convection over tropical Africa and the East Atlantic during the West African monsoon: Regional and diurnal variability
作者: Janiga M.A. ; Thorncroft C.D.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2014
卷: 27, 期: 11 起始页码: 4189
结束页码: 4208
语种: 英语
Scopus关键词: Meteorological radar
; Rain gages
; Conditional rain
; Convective systems
; Diurnal variability
; Moist convection
; Precipitation radar
; Topographic features
; Tropical rainfall measuring mission satellites
; West African Monsoon
; Rain
; atmospheric convection
; convective system
; monsoon
; rainfall
; relative humidity
; stratiform cloud
; TRMM
; Atlantic Ocean
; Atlantic Ocean (East)
; West Africa
英文摘要: The geographic and diurnal variability of moist convection over tropical Africa and the east Atlantic is examined using the Tropical Rainfall Measuring Mission (TRMM) satellite and related to the variability of the convective environment. The stratiform rain fraction is highest within oceanic and continental regions just north of the equator. Both regions have high column relative humidity (CRH). In both monsoon and semiarid continental regions, stratiform rain fractions are significantly higher on days when the CRH is high, which suggests a relationship between these quantities. Large convective systems with high echo tops dominate the rainfall over the Sahel. The importance of CAPE and shear to the development of these types of systems is suggested by the fact these systems are especially common on days when the CAPE and shear are unusually high. Both deep convective and stratiform conditional rain rates increase with the size and echo-top height of convective systems. According to the TRMM Precipitation Radar (PR) near-surface rain rate, the highest deep convective and stratiform conditional rain rates occur off the coast of West Africa. However, comparisons between the PR near-surface rain rate and rain rates computed from Z-R relationships from the literature suggest that deep convective conditional rain rates over the Sahel are underestimated by the TRMMprecipitation algorithm. Over the Sahel, small (large) convective systems produce most of the rainfall in the afternoon (early morning). This is associated with enhanced convective rainfall in the afternoon and stratiform in the early morning. The transition from small to large convective systems as convection propagates away from topographic features is also observed. © 2014 American Meteorological Society. 资助项目: NASA, National Aeronautics and Space Administration
; NSF, National Aeronautics and Space Administration
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/51443
Appears in Collections: 气候变化事实与影响
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作者单位: RSMAS/MPO, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States; University at Albany, State University of New York, Albany, NY, United States
Recommended Citation:
Janiga M.A.,Thorncroft C.D.. Convection over tropical Africa and the East Atlantic during the West African monsoon: Regional and diurnal variability[J]. Journal of Climate,2014-01-01,27(11)