- 1British Antarctic Survey, Atmosphere, Ice and Climate, United Kingdom of Great Britain – England, Scotland, Wales (elcoll56@bas.ac.uk)
- 2School of Ocean and Earth Science, University of Southampton, Southampton, UK
- 3Met Office Hadley Centre, Exeter, UK
- 4Department of Mathematics and Statistics, University of Exeter, UK
- 5National Oceanography Centre, Southampton, UK
Recent research is highlighting the importance of the stratosphere and stratosphere-troposphere coupling for subseasonal-to-seasonal prediction of the winter North Atlantic Oscillation (NAO), the dominant mode of variability in the Northern Hemisphere.
Collingwood et al 2024 demonstrated the relevance of the October upper stratosphere to polar vortex development and predictability of winter NAO. They found that anomalous meridional wind in the upper stratospheric “surf zone”, resulting primarily from anomalous eddy momentum flux convergence, generates a signal that propagates down and impacts the vortex and surface NAO, with correlation coefficients of r=0.36 and 0.40 respectively.
Further investigation finds that the relevance of this upper stratospheric meridional wind to winter NAO is not limited to October, but extends to the preceding summer too. This study seeks to better understand the curious mechanisms dictating this teleconnection as well as its decadal variability.
How to cite: Collingwood, L., Scaife, A., Sinha, B., Marsh, R., Marshall, G., and King, J.: On the predictive value of upper stratosphere dynamics for winter NAO, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10722, https://doi.org/10.5194/egusphere-egu25-10722, 2025.
