Impact of Arctic sea ice loss on the persistence of the Pacific Decadal Oscillation

The decline of Arctic sea ice in response to anthropogenic forcing is accelerating and its variability has recently increased. Previous literature has emphasized the role of sea ice loss in modulating the atmospheric circulations in high- and mid-latitudes. In this study, we aim how the melting of sea ice influences on the North Pacific Ocean, which has been little explored in previous studies. By analyzing various reanalysis datasets and coupled model simulations, we argue that the loss of sea ice in the Arctic may act to lengthen the year-through-year persistence of the Pacific Decadal Oscillation (PDO) along with the change in its dominant periodicity. Thermal forcing due to sea ice loss is associated with a shift of the Aleutian low (AL) associated with the PDO to the south, subsequently, the strengthening of the interactions of PDO and AL in the North Pacific. This results in a lengthening of the PDO persistence. A set of climate model simulations in which the sea ice is reduced with prolonged memory support the observed findings. This implies that the sea ice loss in the Arctic is able to influence the PDO’s persistence with its dominant periodicity and might subsequently feed back to the variation of global surface temperature.