Why Ice Minima Occurred in 2007, '08 and '09

The record low arctic sea ice occurred in September 2007, followed by the second lowest in 2008 and the third lowest in 2009. Although the Dipole Anomaly (DA) has been identified as the major driver, what are the mechanisms for arctic sea ice to gradually recover? This study examines these three cases in a great detail to search for dynamic and thermodynamic sound mechanisms, along with historical observations. It comes to the conclusion that under the thin-ice preconditioning (warming) during winter season by a strong positive Arctic Oscillation (AO) in the 2009 winter, local meridional wind anomaly associated DA during winter to summer is a major forcing for sea ice recovery. Other mechanisms will be discussed.