DOI: 10.1175/JCLI-D-16-0087.1
Scopus记录号: 2-s2.0-85008721589
论文题名: Seasonal transitions and the westerly jet in the Holocene East Asian summer monsoon
作者: Kong W. ; Swensona L.M. ; Chiang J.C.H.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2017
卷: 30, 期: 9 起始页码: 3343
结束页码: 3365
语种: 英语
Scopus关键词: Atmospheric thermodynamics
; Climate change
; Conformal mapping
; Earth atmosphere
; Incident solar radiation
; Jets
; Rain
; Self organizing maps
; Solar radiation
; Asia
; Monsoons
; Paleoclimates
; Rainbands
; Seasonal variability
; Fighter aircraft
; Citrus maxima
英文摘要: The Holocene East Asian summer monsoon (EASM) was previously characterized as a trend toward weaker monsoon intensity paced by orbital insolation. It is demonstrated here that this evolution is more accurately characterized as changes in the transition timing and duration of the EASM seasonal stages (spring, pre-mei-yu, mei-yu, midsummer), and tied to the north-south displacement of the westerlies relative to Tibet. To this end, time-slice simulations across the Holocene are employed using an atmospheric general circulation model. Self-organizing maps are used to objectively identify the transition timing and duration of the EASM seasonal stages. Compared to the late Holocene, an earlier onset of mei-yu and an earlier transition from mei-yu to midsummer in the early to mid-Holocene are found, resulting in a shortened mei-yu and prolonged midsummer stage. These changes are accompanied by an earlier northward positioning of the westerlies relative to Tibet. Invoking changes to seasonal transitions also provides a more satisfactory explanation for two key observations of Holocene East Asian climate: the "asynchronous Holocene optimum" and changes to dust emissions. A mechanism is proposed to explain the altered EASM seasonality in the simulated early to mid-Holocene. The insolation increase over the boreal summer reduces the pole-equator temperature gradient, leading to northward-shifted and weakened westerlies. The meridional position of the westerlies relative to the Tibetan Plateau determines the onset of mei-yu and possibly the onset of the midsummer stage. The northward shift in the westerlies triggers earlier seasonal rainfall transitions and, in particular, a shorter mei-yu and longer midsummer stage. © 2017 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49701
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Geography, Berkeley Atmospheric Sciences Center, University of California-Berkeley, Berkeley, CA, United States; Department of Land, Air and Water Resources, University of California-Davis, Davis, CA, United States
Recommended Citation:
Kong W.,Swensona L.M.,Chiang J.C.H.. Seasonal transitions and the westerly jet in the Holocene East Asian summer monsoon[J]. Journal of Climate,2017-01-01,30(9)