Arctic dipole anomaly

There is a pressure difference between the two regions of the Arctic. High pressure on the North American region and low pressure on the Eurasian region give rice to this Arctic dipole. Arctic dipole leads to drive more Southern winds in to the arctic ocean which affects the melting of sea ice. This said to be the reason behind the recorded sea ice minima during the past few years.

Reference
http://en.wikipedia.org/wiki/Arctic_dipole_anomaly