DOI: 10.1007/s00382-012-1367-3
Scopus记录号: 2-s2.0-84874309735
论文题名: Tropical/extratropical forcing on wintertime variability of the extratropical temperature and circulation
作者: Yu B. ; Lin H.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2013
卷: 40, 期: 2017-05-06 起始页码: 1183
结束页码: 1200
语种: 英语
英文关键词: Dynamic and thermodynamic maintenances
; Temperature and circulation
; Trend
; Tropical/extratropical forcing
; Variability
英文摘要: The secular trends and interannual variability of wintertime temperatures over northern extratropical lands and circulations over the northern hemisphere are examined using the NCEP/NCAR reanalysis from 1961 to 2010. A primitive equation dry atmospheric model, driven by time-averaged forcing in each winter diagnosed from the NCEP reanalysis, is then employed to investigate the influences of tropical and extratropical forcing on the temperature and circulation variability. The model has no topography and the forcing is thus model specific. The dynamic and thermodynamic maintenances of the circulation and temperature anomalies are also diagnosed. Distinct surface temperature trends over 1961-1990 and 1991-2010 are found over most of the extratropical lands. The trend is stronger in the last two decades than that before 1990, particularly over eastern Canadian Arctic, Greenland, and Asia. The exchange of midlatitude and polar air supports the temperature trends. Both the diagnosed extratropical and tropical forcings contribute to the temperature and circulation trends over 1961-1990, while the extratropical forcing dominates tropical forcing for the trends over 1991-2010. The contribution of the tropical forcing to the trends is sensitive to the period considered. The temperature and circulation responses to the diagnosed tropical and extratropical forcings are approximately additive and partially offsetting. Covariances between the interannual surface temperature and 500-hPa geopotential anomalies for the NCEP reanalysis from 1961 to 2010 are dominated by two leading modes associated with the North Atlantic Oscillation (NAO) and Pacific-North American (PNA) teleconnection patterns. The diagnosed extratropical forcing accounts for a significant part of the NAO and PNA associated variability, including the interannual variability of stationary wave anomalies, as well as dynamically and thermodynamically synoptic eddy feedbacks over the North Atlantic and North Pacific. The tropical forcing contributes to the PNA related temperature and circulation variability, but has a small contribution to the NAO associated variability. Additionally, relative contributions of tropical Indian and Pacific forcings are also assessed. © 2012 Her Majesty the queen in the Right of Canada as represented by the Minister of the Environment. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/55047
Appears in Collections: 过去全球变化的重建
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作者单位: Climate Research Division, Environment Canada, 4905 Dufferin Street, Toronto, ON, M3H 5T4, Canada; Meteorological Research Division, Environment Canada, Dorval, QC, Canada
Recommended Citation:
Yu B.,Lin H.. Tropical/extratropical forcing on wintertime variability of the extratropical temperature and circulation[J]. Climate Dynamics,2013-01-01,40(2017-05-06)