Articles | Volume 13, issue 4
Research article
21 Apr 2017
Research article |  | 21 Apr 2017

Influence of North Pacific decadal variability on the western Canadian Arctic over the past 700 years

François Lapointe, Pierre Francus, Scott F. Lamoureux, Mathias Vuille, Jean-Philippe Jenny, Raymond S. Bradley, and Charly Massa

Abstract. Understanding how internal climate variability influences arctic regions is required to better forecast future global climate variations. This paper investigates an annually-laminated (varved) record from the western Canadian Arctic and finds that the varves are negatively correlated with both the instrumental Pacific Decadal Oscillation (PDO) during the past century and also with reconstructed PDO over the past 700 years, suggesting drier Arctic conditions during high-PDO phases, and vice versa. These results are in agreement with known regional teleconnections, whereby the PDO is negatively and positively correlated with summer precipitation and mean sea level pressure respectively. This pattern is also evident during the positive phase of the North Pacific Index (NPI) in autumn. Reduced sea-ice cover during summer–autumn is observed in the region during PDO− (NPI+) and is associated with low-level southerly winds that originate from the northernmost Pacific across the Bering Strait and can reach as far as the western Canadian Arctic. These climate anomalies are associated with the PDO− (NPI+) phase and are key factors in enhancing evaporation and subsequent precipitation in this region of the Arctic. Collectively, the sedimentary evidence suggests that North Pacific climate variability has been a persistent regulator of the regional climate in the western Canadian Arctic. Since projected sea-ice loss will contribute to enhanced future warming in the Arctic, future negative phases of the PDO (or NPI+) will likely act to amplify this positive feedback.

Short summary
Using a unique annually-laminated record (varve) from the western Canadian High Arctic, we found a significant relationship between our varve record and instrumental and reconstructed Pacific Decadal Oscillations (PDOs). The negative (positive) PDO (North Pacific Index) phases increase precipitation as low sea-ice extent, warmer temperature and winds reach our region more efficiently. Our results imply that future negative PDO phases will likely impact the already rapidly warming Arctic.