DOI: 10.1007/s00382-015-2764-1
Scopus记录号: 2-s2.0-84938631574
论文题名: Stratospheric variability of wave activity and parameters in equatorial coastal and tropical sites during the West African monsoon
作者: Kafando P. ; Chane-Ming F. ; Petitdidier M.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 47, 期: 11 起始页码: 3433
结束页码: 3456
语种: 英语
英文关键词: Equatorial and tropical waves
; Gravity waves
; Quasi-biennial oscillation
; Stratospheric variability
; West African monsoon
英文摘要: Recent numerical studies in stratospheric dynamics and its variability as well as climate, have highlighted the need of more observational analyses to improve simulation of the West African monsoon (WAM). In this paper, activity and spectral characteristics of short-scale vertical waves (wavelengths <4 km) are analysed in equatorial coastal and tropical lower stratosphere during the WAM. A first detailed description of such waves over West Africa is derived from high-resolution vertical profiles of temperature and horizontal wind obtained during Intensive Observation Period of the African Monsoon Multidisciplinary Analyses (AMMA) Campaign 2006. Monthly variation of wave energy density is revealed to trace the progression of the inter-tropical convergence zone (ITCZ) over West Africa. Mesoscale inertia gravity-waves structures with vertical and horizontal wavelengths of 1.5–2.5 and 400–1100 km respectively and intrinsic frequencies of 1.1–2.2 f or periods <2 days are observed in the tropical LS with intense activity during July and August when the WAM is installed over the tropical West Africa. Over equatorial region, gravity waves with intrinsic frequencies of 1.4–4 f or periods <5.2 days, vertical wavelength of 2.1 km and long horizontal wavelengths of 1300 km are intense during the WAM coastal phase. From July to October, gravity waves with intrinsic frequencies of 1.2–3.8 f or periods <6 days, vertical wavelength of 2.1 km and horizontal wavelengths of 1650 km are less intense during the WAM Sahelian phase of the WAM, March–June. Unlike potential energy density, kinetic energy density is observed to be a good proxy for the activity of short-scale vertical waves during the WAM because quasi-inertial waves are dominant. Long-term wave activity variation from January 2001 to December 2009, highlights strong year-to-year variation superimposed on convective activity and quasi-biennial oscillation-like variations especially above tropical stations. © 2015, The Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53427
Appears in Collections: 过去全球变化的重建
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作者单位: Laboratoire de Physique et de Chimie de l’Environnement, Dpt. de Physique, Université de Ouagadougou, UFR-SEA, 03, B.P. 7021, Ouagadougou, Burkina Faso; Laboratoire de l’Atmosphère et des Cyclones, Université de la Réunion, UMR 8105, UMR CNRS-Météo France-Université, La Réunion, France; Université Versailles Saint-Quentin, CNRS/INSU, LATMOS-IPSL, 11 Boulevard d’Alembert, Guyancourt, France
Recommended Citation:
Kafando P.,Chane-Ming F.,Petitdidier M.. Stratospheric variability of wave activity and parameters in equatorial coastal and tropical sites during the West African monsoon[J]. Climate Dynamics,2016-01-01,47(11)