Climate change has led to frequent large wildfires in the western United States, and extreme fires result from the nexus of weather and biophysical processes, which makes fire prediction challenging. The complexity of these interactions among human and natural dimensions of fire activity in the presence of natural variability in the climate system confounds the detection and attribution of changes in large wildfires over this region.
There are emerging connections between high-latitude environmental change and mid-latitude weather extremes in both warm and cold seasons of the past few decades, then the question has been raised “ what is the relation that link it to large wildfires? “
Dr. Zuowei Xie cooperated with Dr. Yufei Zou of PNNL to study the physical process of Arctic Sea ice decrease leading to large wildfires in California.In this research, they use a series of observation-/reanalysis-/model-based diagnostics and climate model sensitivity experiments to investigate the linkage between declining sea ice in the Arctic and worsening fire hazards in the western U.S. over the past four decades.
The results show that the declines in Arctic sea ice is conducive to the maintenance of the low pressure in the Bering Strait. On the one hand, it is conducive to the development of the downstream high pressure. On the other hand, it also strengthens the rapids and disturbance, which in turn feeds back to the dipole circulation, which eventually leads to the frequent fires on the west coast of North America.
The article was published in Nature Communication entitled "Increasing large wildfires over the western United States linked to diminishing sea ice in the Arctic".
