The Pacific Decadal Oscillation (PDO) modulation due to Arctic sea ice loss

The declining trends in Arctic sea ice cover have accelerated and multi-year sea ice has been reduced, which has increased the variability of sea ice extent in recent decades. Previous studies revealed that role of sea ice loss in modulating the atmospheric circulation in high and mid latitudes leading to extreme weathers, such as severe winters in North America and Eurasia. However, there are little studies the impact of sea ice loss on the ocean. We argue that sea ice loss in the Pacific Arctic sector (PAS), accompanied by atmospheric circulation change, has potential impacts on the ocean, affecting global climate in an unique way. That is, change of characteristics of sea ice area in reducing trend and larger and prolonged variance may influence the Pacific Decadal Oscillation (PDO), which is the first dominant mode of SST in the North Pacific. A set of climate model simulations in which the sea ice is reduced with prolonged memory support the observed results. This implies that the sea-ice loss in the PAS, which might be due to anthropogenic forcing, is able to influence the PDO's persistence with its dominant periodicity, which in turn can feed back to the variation of global surface temperature.