DOI: 10.1002/2017JD026542
论文题名: Nearly identical cycles of the quasi-biennial oscillation in the equatorial lower stratosphere
作者: Dunkerton T.J.
刊名: Journal of Geophysical Research: Atmospheres
出版年: 2017
卷: 122, 期: 16 起始页码: 8467
结束页码: 8493
语种: 英语
英文关键词: cluster analysis
; Quasi-Biennial Oscillation
; rawinsonde
; RPCA
; seasonal cycle
英文摘要: As a nonlinear dynamical system with limit cycles but subject to periodic forcings associated with the seasonal cycle, the quasi-biennial oscillation (QBO) displays seasonal modulation such that phase transitions are more likely to occur in certain months than in others. Modulation is distinct from seasonal synchronization, defined as quantized QBO periods and identical cycles. Instead, nearly identical QBO cycles can be identified in the data having similar period, internal structure, and (optionally) timing with respect to the calendar year. Four such categories are found using a spectral phase method based on the 2-D phase space of the leading rotated principal components (RPCs) of near-equatorial monthly mean zonal wind in the layer 70–10 hPa. The most prominent category, containing as many as 15 cycles of the 28 observed thus far, is “nearly biennial” with period slightly greater than 24 months. All results, prior to the recent QBO anomaly in Cycle 28, are demonstrated to be statistically stationary in the sense that the RPCs are temporally invariant and insensitive to the inclusion of data to 100 hPa and with higher vertical resolution. Inclusion of Cycle 28 has no effect on the rotated empirical orthogonal functions but a microscopic change in the long-term average, since strong easterlies are missing in the anomalous cycle. For objective definition of QBO cycles in physical space-time, westerly onsets in the 40–53 hPa layer are least likely to stall and provide unambiguous starting times. Half of these onsets cluster in April–May, consistent with the seasonal modulation obtained with the spectral phase method. ©2017. American Geophysical Union. All Rights Reserved. 资助项目: "Monthly mean zonal wind data were obtained from the Free University of Berlin, http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/qbo/. The diligence and constructive comments of three anonymous reviewers contributed substantially to the excellence of this paper. T.J.D. is supported by the National Science Foundation.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/62604
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: NorthWest Research Associates, Redmond, WA, United States
Recommended Citation:
Dunkerton T.J.. Nearly identical cycles of the quasi-biennial oscillation in the equatorial lower stratosphere[J]. Journal of Geophysical Research: Atmospheres,2017-01-01,122(16)