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Spatio-temporal Properties of the Extratropical Atmospheric Circulation

Wednesday, September 26, 2001 - 11:00am - 12:00pm
Keller 3-180
Anastasios Tsonis (University of Wisconsin)
The atmospheric general circulation often enters into regimes that cause weather anomalies to persist over areas of the globe. By considering 500-hPa measurements we demonstrate the existence of scale invariance in the variability of extratropical atmospheric circulation anomalies over the whole range of timescales resolved by the available data, from a week to a decade. We find that this scale invariance is consistent with atmospheric dynamics and indicates that the memory of the climate system is not confined only to large scales but extends to small scales as well. By investigating the hemispheric structure of the 500-hPa fields in the last 34 years we were able to link this scale invariance to anomaly patterns that exhibit strong spatial coherence and a seemingly decadal variability. We relate these findings to climate processes considered in the recent literature and we discuss the implications of such a property of the general circulation for modeling and prediction of the climate system response.