Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1007/s00382-017-3628-7 |
Mesoscale convective systems and nocturnal rainfall over the West African Sahel: role of the Inter-tropical front | |
Vizy, Edward K.; Cook, Kerry H. | |
2018 | |
发表期刊 | CLIMATE DYNAMICS |
ISSN | 0930-7575 |
EISSN | 1432-0894 |
出版年 | 2018 |
卷号 | 50页码:587-614 |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | A convection-permitting regional model simulation for August 2006 and observations are evaluated to better understand the diurnal cycle of precipitation over the Sahel. In particular, reasons for a nocturnal rainfall maximum over parts of the Sahel during the height of the West African monsoon are investigated. A relationship between mesoscale convective system (MCS) activity and inter-tropical front (ITF)/dryline dynamics is revealed. Over 90% of the Sahel nocturnal rainfall derives from propagating MCSs that have been associated with topography in earlier studies. In contrast, in this case study, 70-90% of the nocturnal rainfall over the southern Sahel (11 degrees-14 degrees) west of 15 degrees E is associated with MCSs that originate less than 1000 km upstream (to the north and east) in the afternoon, in a region largely devoid of significant orography. This MCS development occurs in association with the Sahel ITF, combined with atmospheric pre-conditioning. Daytime surface heating generates turbulent mixing that promotes planetary boundary layer (PBL) growth accompanied by a low-level reversal in the meridional flow. This enhances wind convergence in the low-level moist layer within 2 degrees-3 degrees of latitude of the equatorward side of the ITF. MCSs tend to form when this vertical mixing extends to the level of free convection and is accompanied by a mid-tropospheric African easterly wave disturbance to the east. This synoptic disturbance enhances the vertical wind shear and atmospheric instability over the genesis location. These results are found to be robust across the region. |
英文关键词 | Mesoscale convective system Inter-tropical front Dryline Diurnal cycle of precipitation West Africa Sahel MCS genesis |
领域 | 气候变化 |
收录类别 | SCI-E |
WOS记录号 | WOS:000422908700037 |
WOS关键词 | ICE-SCATTERING SIGNATURE ; SEVERE STORM ENVIRONMENT ; EASTERLY WAVES ; DIURNAL CYCLE ; SQUALL LINES ; GLOBAL PRECIPITATION ; PASSIVE MICROWAVE ; TROPICAL AFRICA ; PART I ; JET |
WOS类目 | Meteorology & Atmospheric Sciences |
WOS研究方向 | Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/36094 |
专题 | 气候变化 |
作者单位 | Univ Texas Austin, Jackson Sch Geosci, Dept Geol Sci, Austin, TX 78712 USA |
推荐引用方式 GB/T 7714 | Vizy, Edward K.,Cook, Kerry H.. Mesoscale convective systems and nocturnal rainfall over the West African Sahel: role of the Inter-tropical front[J]. CLIMATE DYNAMICS,2018,50:587-614. |
APA | Vizy, Edward K.,&Cook, Kerry H..(2018).Mesoscale convective systems and nocturnal rainfall over the West African Sahel: role of the Inter-tropical front.CLIMATE DYNAMICS,50,587-614. |
MLA | Vizy, Edward K.,et al."Mesoscale convective systems and nocturnal rainfall over the West African Sahel: role of the Inter-tropical front".CLIMATE DYNAMICS 50(2018):587-614. |
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