| DOI: | 10.1175/JCLI-D-12-00475.1
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| Scopus记录号: | 2-s2.0-84884255621
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| 论文题名: | A nonlinear response of sahel rainfall to atlantic warming |
| 作者: | Neupane N.; Cook K.H.
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| 刊名: | Journal of Climate
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| ISSN: | 8948755
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| 出版年: | 2013
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| 卷: | 26, 期:18 | | 起始页码: | 7080
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| 结束页码: | 7096
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| 语种: | 英语
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| Scopus关键词: | Coastal precipitation
; Geo-potential heights
; Global warming problems
; Moist static energy
; Moisture transport
; Non-linear response
; Regional climate modeling
; Thermal profiles
; Global warming
; Moisture
; Rain
; advection
; anomaly
; climate modeling
; climate prediction
; convection
; geopotential
; global warming
; moisture transfer
; precipitation (climatology)
; rainfall
; regional climate
; westerly
; wind
; Atlantic Ocean
; Gulf of Guinea
; Sahel [Sub-Saharan Africa]
; West Africa
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| 英文摘要: | The response over West Africa to uniform warming of the Atlantic Ocean is analyzed using idealized simulations with a regional climate model. With warming of 1 and 1.5 K, rainfall rates increase by 30%-50% over most of West Africa. With Atlantic warming of 2K and higher, coastal precipitation increases but Sahel rainfall decreases substantially. This nonlinear response in Sahel rainfall is the focus of this analysis. Atlantic warming is accompanied by decreases in low-level geopotential heights in the Gulf of Guinea and in the largescale meridional geopotential height gradient. This leads to easterly wind anomalies in the central Sahel. With Atlantic warming below 2K, these easterly anomalies support moisture transport from the Gulf of Guinea and precipitation increases. With Atlantic warming over 2K, the easterly anomalies reverse the westerly flow over the Sahel. The resulting dry air advection into the Sahel reduces precipitation. Increased low-level moisture provides moist static energy to initiate convection with Atlantic warming at 1.5K and below, while decreased moisture and stable thermal profiles suppress convection with additional warming. In all simulations, the southerly monsoon flow onto the Guinean coast is maintained and precipitation in that region increases. The relevance of these results to the global warming problem is limited by the focus on Atlantic warming alone. However, confident prediction of climate change requires an understanding of the physical processes of change, and this paper contributes to that goal. © 2013 American Meteorological Society. |
| 资助项目: | U.S. Department of Energy
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| Citation statistics: |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/51656
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| Appears in Collections: | 气候变化事实与影响
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作者单位: | Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, United States
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| Recommended Citation: | |
Neupane N.,Cook K.H.. A nonlinear response of sahel rainfall to atlantic warming[J]. Journal of Climate,2013-01-01,26(18)
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