Linking past flood frequencies in Norway to regional atmospheric circulation anomalies
Article first published online: 22 AUG 2011
Copyright © 2011 John Wiley & Sons, Ltd.
Journal of Quaternary Science
Volume 27, Issue 1, pages 71–80, January 2012
How to Cite
Støren, E. N., Kolstad, E. W. and Paasche, Ø. (2012), Linking past flood frequencies in Norway to regional atmospheric circulation anomalies. J. Quaternary Sci., 27: 71–80. doi: 10.1002/jqs.1520
- Issue published online: 9 JAN 2012
- Article first published online: 22 AUG 2011
- Manuscript Accepted: 17 APR 2011
- Manuscript Revised: 14 APR 2011
- Manuscript Received: 13 DEC 2010
- atmospheric circulation;
- North Atlantic Oscillation;
Analysis of two continuous, high-resolution palaeo-flood records from southern Norway reveals that the frequency of extreme flood events has changed significantly during the Holocene. During the early and middle Holocene, flood frequency was low; by contrast, it was high over the last 2300 years when the mean flood frequency was about 2.5–3.0 per century. The present regional discharge regime is dominated by spring/summer snowmelt, and our results indicate that the changing flood frequency cannot be explained by local conditions associated with the respective catchments of the two lakes, but rather long-term variations of solid winter precipitation and related snowmelt. Applying available instrumental winter precipitation data and associated sea-level pressure re-analysis data as a modern analogue, we document that atmospheric circulation anomalies, significantly different from the North Atlantic Oscillation (NAO), have some potential in explaining the variability of the two different palaeo-flood records. Centennial-scale patterns in shifting flood frequency might be indicative of shifts in atmospheric circulation and shed light on palaeo-pressure variations in the North Atlantic region, in areas not influenced by the NAO. Major shifts are found at about 2300, 1200 and 200 years ago (cal. a BP). Copyright © 2011 John Wiley & Sons, Ltd.