Extra-tropical synoptic cyclones and downward propagating anomalies in the Northern Annular Mode
Article first published online: 5 APR 2008
Copyright 2008 by the American Geophysical Union.
Geophysical Research Letters
Volume 35, Issue 7, April 2008
How to Cite
2008), Extra-tropical synoptic cyclones and downward propagating anomalies in the Northern Annular Mode, Geophys. Res. Lett., 35, L07809, doi:10.1029/2007GL032972.(
- Issue published online: 5 APR 2008
- Article first published online: 5 APR 2008
- Manuscript Accepted: 6 MAR 2008
- Manuscript Revised: 25 FEB 2008
- Manuscript Received: 11 DEC 2007
- stratosphere-troposphere interaction;
- synoptic cyclones;
- eddy-mean flow interaction
 During most winters, anomalies in the Northern Annular Mode (NAM) propagate downward from the stratosphere to the troposphere. In this paper, the relationship between extra-tropical synoptic-scale cyclones and downward propagating positive (NAM+) and negative (NAM−) anomalies is investigated. Both Pacific and Atlantic storm tracks are significantly influenced by the downward propagating NAM+ anomalies, while only the Atlantic storm tracks are significantly influenced by the downward propagating NAM− anomalies. The number of cyclones changes by up to 30 % during both NAM+ and NAM− within certain regions. Also, fluctuations in the NAM follow corresponding fluctuations in the storm activity with a lag of three days during NAM+ and NAM−.