DOI: 10.5194/cp-10-1125-2014
Scopus记录号: 2-s2.0-84902499752
论文题名: Centennial-scale variability of the Southern Hemisphere westerly wind belt in the eastern Pacific over the past two millennia
作者: Koffman B.G. ; Kreutz K.J. ; Breton D.J. ; Kane E.J. ; Winski D.A. ; Birkel S.D. ; Kurbatov A.V. ; Handley M.J.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2014
卷: 10, 期: 3 起始页码: 1125
结束页码: 1144
语种: 英语
Scopus关键词: El Nino-Southern Oscillation
; ice core
; Medieval Warm Period
; paleoclimate
; particle size
; Southern Hemisphere
; westerly
; wind direction
; Antarctic Ice Sheet
; Antarctica
; West Antarctic Ice Sheet
; West Antarctica
英文摘要: We present the first high-resolution (sub-annual) dust particle data set from West Antarctica, developed from the West Antarctic Ice Sheet (WAIS) Divide deep ice core (79.468° S, 112.086 W), and use it to reconstruct changes in atmospheric circulation over the past 2400 years. We find a background dust flux of ∼4 mg mĝ̂'2 yearĝ̂'1 and a mode particle size of 5-8 Î1/4m diameter. Through comparing the WAIS Divide record with other Antarctic ice core particle records, we observe that coastal and lower-elevation sites have higher dust fluxes and coarser particle size distributions (PSDs) than sites on the East Antarctic plateau, suggesting input from local dust sources at these lower-elevation sites. In order to explore the use of the WAIS Divide dust PSD as a proxy for past atmospheric circulation, we make quantitative comparisons between both mid-latitude zonal wind speed and West Antarctic meridional wind speed and the dust size record, finding significant positive interannual relationships. We find that the dust PSD is related to mid-latitude zonal wind speed via cyclonic activity in the Amundsen Sea region. Using our PSD record, and through comparison with spatially distributed climate reconstructions from the Southern Hemisphere (SH) middle and high latitudes, we infer that the SH westerlies occupied a more southerly position from circa 1050 to 1400 CE (Common Era), coinciding with the Medieval Climate Anomaly (MCA). Subsequently, at ca. 1430 CE, the wind belt shifted equatorward, where it remained until the mid-to-late twentieth century. We find covariability between reconstructions of El Niño-Southern Oscillation (ENSO) and the mid-latitude westerly winds in the eastern Pacific, suggesting that centennial-scale circulation changes in this region are strongly influenced by the tropical Pacific. Further, we observe increased coarse particle deposition over the past 50 years, consistent with observations that the SH westerlies have been shifting southward and intensifying in recent decades. © Author(s) 2014. CC Attribution 3.0 License. 资助项目: NSF, National Stroke Foundation
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49258
Appears in Collections: 气候变化与战略
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Recommended Citation:
Koffman B.G.,Kreutz K.J.,Breton D.J.,et al. Centennial-scale variability of the Southern Hemisphere westerly wind belt in the eastern Pacific over the past two millennia[J]. Climate of the Past,2014-01-01,10(3)