Investigation of the atmospheric mechanisms related to the autumn sea ice and winter circulation link in the Northern Hemisphere

• Published in: Climate Dynamics
• Main Authors: King, Martin P., Hell, Momme, Keenlyside, Noel S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2016
• Subjects: Kara Sea; North Atlantic; North Atlantic oscillation; Sea ice
• Online Access: https://oceanrep.geomar.de/id/eprint/31720/; https://oceanrep.geomar.de/id/eprint/31720/1/King_2016.pdf; https://doi.org/10.1007/s00382-015-2639-5

The relationship of Barents-Kara sea ice concentration in October and November with atmospheric circulation in the subsequent winter is examined using reanalysis and observational data. The analyses are performed on data with the 5-year running means removed to reduce the potential effects of slowly-varying external driving factors, such as global warming. We show that positive (negative) Barents-Kara sea ice concentration anomaly in autumn is associated with a positive (negative) North Atlantic Oscillation-like (NAO) pattern with lags of up to 3 months. The month-to-month variations in the lag relationships of the atmospheric anomalies related to November sea ice concentration are presented. Further analysis shows that the stratosphere-troposphere interaction may provide the memory in the system: positive (negative) sea ice concentration anomaly in November is associated with a strengthened (weakened) stratospheric polar vortex and these anomalies propagate downward leading to the positive (negative) NAO-like pattern in the late December to early January. This stratosphere mechanism may also play a role for Barents-Kara sea ice anomaly in December, but not for September and October. Consistently, Eliassen-Palm, eddy heat and momentum fluxes suggest that there is strong forcing of the zonal winds in November.