DOI: 10.1175/JCLI-D-18-0173.1
Scopus记录号: 2-s2.0-85061647334
论文题名: A Systematic comparison of tropical waves over northern Africa. Part I: Influence on rainfall
作者: Schlueter A. ; Fink A.H. ; Knippertz P. ; Vogel P.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2019
卷: 32, 期: 5 起始页码: 1501
结束页码: 1523
语种: 英语
Scopus关键词: Climatology
; Gravity waves
; Rain gages
; Time measurement
; Tropics
; African easterly waves
; High frequency waves
; Intraseasonal time scale
; Low-latitude rainfall
; Madden-Julian oscillation
; Rain gauge networks
; Rainfall variability
; Tropical disturbances
; Rain
英文摘要: Low-latitude rainfall variability on the daily to intraseasonal time scale is often related to tropical waves, including convectively coupled equatorial waves, the Madden-Julian oscillation (MJO), and tropical disturbances (TDs). Despite the importance of rainfall variability for vulnerable societies in tropical Africa, the relative influence of tropical waves for this region is largely unknown. This article presents the first systematic comparison of the impact of six wave types on precipitation over northern tropical Africa during the transition and full monsoon seasons, using two satellite products and a dense rain gauge network. Composites of rainfall anomalies in the different datasets show comparable modulation intensities in the West Sahel and at the Guinea Coast, varying from less than 2 to above 7mmday -1 depending on the wave type. African easterly waves (AEWs) and Kelvin waves dominate the 3-hourly to daily time scale and explain 10%-30%locally. On longer time scales (7-20 days), only the MJO and equatorial Rossby (ER) waves remain as modulating factors and explain about up to one-third of rainfall variability. Eastward inertio-gravity waves and mixed Rossby- gravity (MRG) waves are comparatively unimportant. An analysis of wave superposition shows that lowfrequency waves (MJO, ER) in their wet phase amplify the activity of high-frequency waves (TD, MRG) and suppress them in the dry phase. The results stress that more attention should be paid to tropical waves when forecasting rainfall over northern tropical Africa. © 2019, American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/117202
Appears in Collections: 气候变化与战略
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Recommended Citation:
Schlueter A.,Fink A.H.,Knippertz P.,et al. A Systematic comparison of tropical waves over northern Africa. Part I: Influence on rainfall[J]. Journal of Climate,2019-01-01,32(5)