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

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

doi:10.5194/cp-13-411-2017

Abstract

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.

Highlights

In the North Pacific region, the Pacific Decadal Oscillation (PDO) is the major mode of multi-decadal climate variability (Mantua et al, 1997)
This paper investigates an annually-laminated 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 with reconstructed PDO over the past 700 years, suggesting drier Arctic conditions during high-PDO phases, and vice versa
Several key climate indices demonstrate the present-day influence of the PDO on the western Canadian Arctic

Summary

Introduction

In the North Pacific region, the Pacific Decadal Oscillation (PDO) is the major mode of multi-decadal climate variability (Mantua et al, 1997). The PDO can be described as a longlived pattern of Pacific sea surface temperature (SST) variability similar to the El Niño–Southern Oscillation (ENSO) (Allan et al, 1996; Zhang et al, 1997) or as a low-frequency residual of ENSO variability on multi-decadal timescales (Newman et al, 2003). During PDO−, conditions are essentially reversed (Mantua and Hare, 2002).

Methods

Results

Conclusion