DOI: 10.1175/JCLI-D-11-00653.1
Scopus记录号: 2-s2.0-84872911607
论文题名: The relationship of rainfall variability in western equatorial Africa to the tropical oceans and atmospheric circulation. Part I: The boreal spring
作者: Nicholson S.E. ; Dezfuli A.K.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2013
卷: 26, 期: 1 起始页码: 45
结束页码: 65
语种: 英语
Scopus关键词: Atlantic Ocean
; Atmosphere-ocean system
; Atmospheric circulation
; Atmospheric parameters
; Boreal Spring
; Equatorial Africa
; Global tropics
; Interannual variability
; Rainfall variability
; Rainy seasons
; Remote forcing
; Sea surface temperatures
; South Atlantic
; Strong link
; Tropical ocean
; Wet and dry
; Zonal wind
; Atmospheric temperature
; Climatology
; Nickel compounds
; Rain
; Tropics
; annual variation
; atmospheric circulation
; El Nino
; La Nina
; ocean
; rainfall
; sea surface temperature
; subtropical region
; westerly
; zonal wind
; Atlantic Ocean
; Atlantic Ocean (South)
; Indian Ocean
英文摘要: This paper examines the factors governing rainfall variability in western equatorial Africa (WEA) during the April-June rainy season. In three of the five regions examined some degree of large-scale forcing is indicated, particularly in the region along theAtlantic coast. Interannual variability in this coastal sector also demonstrates a strong link to changes in local sea surface temperatures (SSTs) and the South Atlantic subtropical high. To examine potential causal mechanisms, various atmospheric parameters are evaluated for wet and dry composites. The results suggest that the intensity of the zonal circulation in the global tropics is a crucial control on rainfall variability over WEA. A La Nin~ a (El Nin~ o)-like signal in both SSTs and zonal circulation over the Pacific is apparent in association with the wet (dry) conditions in the western sector. However, remote forcing from the Pacific modulates the circulation over Africa indirectly by way of synchronous changes in the entire Indian or Atlantic Ocean. Anomalies in the local zonal winds are similar in all three regions: the wet (dry) composite is associated with an intensification (weakening) of the upper-tropospheric easterlies and low-level westerlies, but a weakening (intensification) of the midlevel easterlies. This work also suggests that, in most cases, the relationship between local SSTs and rainfall reflects a common remote forcing by the large-scale atmosphere-ocean system. This forcing is manifested via changes in the zonal circulation. Thus, the statistical associations between rainfall and SSTs do not indicate direct forcing by local SSTs. One point of evidence for this conclusion is the stronger association with atmospheric parameters than with SSTs. © 2013 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/52088
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Earth, Ocean and Atmospheric Science, The Florida State University, Tallahassee, FL, United States; Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, United States
Recommended Citation:
Nicholson S.E.,Dezfuli A.K.. The relationship of rainfall variability in western equatorial Africa to the tropical oceans and atmospheric circulation. Part I: The boreal spring[J]. Journal of Climate,2013-01-01,26(1)