Spatio-Temporal Linkages between Declining Arctic Sea-Ice Extent and Increasing Wildfire Activity in the Western United States

Paul Knapp,Peter Soulé

doi:10.3390/f8090313

Paul Knapp, Peter Soulé

Open Access

https://doi.org/10.3390/f8090313

Copy DOI

Abstract

We examined relationships between monthly Arctic sea-ice extent (ASIE) and annual wildfire activity for seven regions in the western United States during 1980–2015 to determine if spatio-temporal linkages exist between ASIE, upper-level flow, and surface climatic conditions conducive to western U.S. wildfire activity. Winter ASIE had significant (p 36,000 ha) in area burned in the western U.S. since 1980.

Highlights

Arctic sea-ice extent (ASIE) during winter 2017 was the lowest recorded value since satellite records began in 1979 and monthly ASIE levels in the past year were consistently more than two standard deviations below the 1981–2010 average [1]
We have identified a new and potentially substantive connection between decreasing ASIE and increasing wildfire activity in the western U.S during 1980–2015, which if operative represents the strongest multi-region-wide climate teleconnection
Our findings suggest a broad-scale teleconnective feature related to ASIE that indirectly modulates wildfire activity with evidence that summertime 300-hPa flow is influenced by prior-winter ASIE

Summary

Introduction

Arctic sea-ice extent (ASIE) during winter 2017 was the lowest recorded value since satellite records began in 1979 and monthly ASIE levels in the past year were consistently more than two standard deviations below the 1981–2010 average [1]. Warm-season impacts associated with increased meridionality and persistence occur [9,10,11], including more frequent ridging (i.e., higher atmospheric pressure) over the Pacific Northwest and Northern Rockies regions of the coterminous U.S. The relationships between ASIE, atmospheric flow patterns/modes of variation (e.g., North Atlantic Oscillation; NAO), and surface weather conditions are complex [12], and likely synergistic with other potential controls such as snow cover extent in Eurasia [13]. Marked increases in wildland fire activity and the cost associated with fire control during the past two decades [24] have been concurrent with declining ASIE, suggesting a potential interactive effect. We examine the relationship between reduced sea-ice cover and increased wildfire activity for seven regions in the western U.S we hypothesize that a spatio-temporal linkage between ASIE and upper-level flow exists and modulates surface climatic conditions in the western U.S that are favorable for enhanced wildfire activity

Data and Methods

Results

Siberian

Findings

Discussion

Conclusions