DOI: 10.1002/grl.50273
论文题名: Are vegetation-related roughness changes the cause of the recent decrease in dust emission from the Sahel?
作者: Cowie S.M. ; Knippertz P. ; Marsham J.H.
刊名: Geophysical Research Letters
ISSN: 0094-9118
EISSN: 1944-8849
出版年: 2013
卷: 40, 期: 9 起始页码: 1868
结束页码: 1872
语种: 英语
英文关键词: decadal trends
; dust emission
; roughness length
; Sahel
; vegetation
; wind-speed
Scopus关键词: decadal trends
; Dust emission
; Roughness length
; Sahel
; wind-speed
; Dust
; Soil moisture
; Vegetation
; Water supply
; Wind effects
; Surface roughness
; data set
; decadal variation
; dust
; evapotranspiration
; land use change
; soil moisture
; trend analysis
; turbulence
; vegetation structure
; wind velocity
; Atlantic Ocean
; Atlantic Ocean (Tropical)
; Sahel [Sub-Saharan Africa]
英文摘要: Since the 1980s, a dramatic downward trend in North African dustiness and transport to the tropical Atlantic Ocean has been observed by different data sets and methods. The precise causes of this trend have previously been difficult to understand, partly due to the sparse observational record. Here we show that a decrease in surface wind speeds associated with increased roughness due to more vegetation in the Sahel is the most likely cause of the observed drop in dust emission. Associated changes in turbulence and evapotranspiration, and changes in large-scale circulation, are secondary contributors. Past work has tried to explain negative correlations between North African dust and precipitation through impacts on emission thresholds due to changes in soil moisture and vegetation cover. The use of novel diagnostic tools applied here to long-term surface observations suggests that this is not the dominating effect. Our results are consistent with a recently observed global decrease in surface wind speed, known as "stilling", and demonstrate the importance of representing vegetation-related roughness changes in models. They also offer a new mechanism of how land-use change and agriculture can impact the Sahelian climate. Key Points Decadal Sahel dust trends analyzed with surface observations and new diagnosticsWind-speed changes dominate over soil changes in recent dust emission decreaseVegetation-induced roughness changes are the main control on wind-speed trends ©2013. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879105742&doi=10.1002%2fgrl.50273&partnerID=40&md5=20080c4a86ff595ffb5508cf7002d0eb
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/6382
Appears in Collections: 气候减缓与适应
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作者单位: Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
Recommended Citation:
Cowie S.M.,Knippertz P.,Marsham J.H.. Are vegetation-related roughness changes the cause of the recent decrease in dust emission from the Sahel?[J]. Geophysical Research Letters,2013-01-01,40(9).