Northern hemisphere teleconnection patterns during extreme phases of the zonal-mean circulation

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · Journal of Climate

DOI:https://doi.org/10.1175/1520-0442(1996)009<2614:NHTPDE>2.0.CO;2· OSTI ID:411856

Ting, Mingfang ^[1]; Hoerling, M P; Xu, Taiyi ^[2]

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1. Univ. of Illinois, Urbana, IL (United States)
2. Univ. of Colorado, Boulder, CO (United States); and others

Regional climate anomalies associated with year-to-year changes in the tropospheric zonal-mean zonal wind ({mu}) are examined. This study focuses on the wintertime Northern Hemisphere extratronics and compares seasonal mean anomalies associated with {mu} to those associated with the El Nino-Southern Oscillation during the 1947-94 period. Dynamical model experiments indicate that a single zonal index, characterized by out-of-phase {mu} anomalies at 35{degrees} and 55{degrees}N, is of primary importance for zonal flow/stationary wave interactions in the Northern Hemisphere extratropics. Such fluctuations in the zonal-mean zonal flow are shown to occur independently of tropical SST variability, consistent with earlier studies. Dynamical model experiments and regression analyses of the historical data indicate that such a zonal index explains a significant fraction of the wintertime stationary wave variability in several regions. The principal centers of action reside within wave trains over the North Pacific-North American region and the North Atlantic-Eurasian region where locally 30%-40% of the eddy height variability is explained by the zonal index. Only over the North Pacific does the stationary wave signal related to ENSO appreciably exceed that associated with the zonal index. Only over the North Pacific does the stationary wave signal related to ENSO appreciably exceed that associated with the zonal index. The surface climate associated with the zonal index is described by a wavenumber 1 pattern, which has out-of-phase temperature anomalies between Eurasia and North America and amplitudes considerably larger than those experienced during ENSO. 35 refs., 10 figs.

• Sponsoring Organization: USDOE
• OSTI ID: 411856
• Journal Information: Journal of Climate, Journal Name: Journal of Climate Journal Issue: 10 Vol. 9; ISSN JLCLEL; ISSN 0894-8755
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CLIMATIC CHANGE
CORRELATIONS
FLUCTUATIONS
NORTHERN HEMISPHERE
SOUTHERN OSCILLATION
WIND