DOI: 10.1007/s00382-016-3421-z
Scopus记录号: 2-s2.0-84994218620
论文题名: The El Niño effect on Ethiopian summer rainfall
作者: Gleixner S. ; Keenlyside N. ; Viste E. ; Korecha D.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2017
卷: 49, 期: 2017-05-06 起始页码: 1865
结束页码: 1883
语种: 英语
英文关键词: ENSO
; Ethiopia
; Kiremt
; Walker-circulation
英文摘要: While El Niño is known to cause failure of Kiremt (boreal summer) rainfall in Ethiopia, the mechanisms are not fully understood. Here we use the ECHAM5 Atmospheric General Circulation Model to investigate the physical link between Pacific sea surface temperature (SST) anomalies and Kiremt rainfall. We compare ECHAM5 simulations forced with reconstructed SST data, to gauge-based rainfall observations and atmospheric reanalysis for the time period of 1961–2009. We perform composite analysis and sensitivity experiments driven only with equatorial Pacific SST anomalies. Our results show warm SST anomalies in the equatorial Pacific drive a corresponding large-scale circulation anomaly with subsidence over Ethiopia in dry Kiremt seasons. Horizontal wind fields show a slow-down of the whole Indian monsoon system with a weaker Tropical Easterly Jet and a weaker East African Low-Level Jet in these summers. These changes can be seen as an anomalous circulation cell over northern Africa with westerlies at 100–200 hPa and easterlies below 500 hPa. Surface easterlies might reduce the moisture inflow from the Atlantic and Congo basin into Ethiopia. This and the general subsidence over the region could explain the reduction in Kiremt rainfall. Our results suggest up to 50% of the Kiremt rainfall anomalies is driven by equatorial Pacific SST variability. © 2016, The Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53081
Appears in Collections: 过去全球变化的重建
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作者单位: Geophysical Institute and Bjerknes Centre for Climate Research, University of Bergen, Postboks 7803, Bergen, Norway; Nansen Environmental and Remote Sensing Center, Thormøhlens Gate 47, Bergen, Norway; National Meteorology Agency for Ethiopia, Qelebet Menged, Addis Ababa, Ethiopia
Recommended Citation:
Gleixner S.,Keenlyside N.,Viste E.,et al. The El Niño effect on Ethiopian summer rainfall[J]. Climate Dynamics,2017-01-01,49(2017-05-06)