Arctic Oscillation and Pacific-North American pattern dominated-modulation of fire danger and wildfire occurrence

Based on statistical analyses and Arctic Oscillation (AO) and the Pacific-North American pattern (PNA) induced climate anomalies in the 2001–2020 interval, it has been found that these climate modes drastically influence the fire danger (PFIv2) in differing ways across coastal and inland regions. The AO induces higher fire risk in northern Eurasia and central North America, whereas the PNA increases the fire danger across southern Asia and western North America. Moreover, fires have been predominantly identified, up to 70%, during the positive phases of AO and PNA northward of 50°N, in particular over Alaska, Baltic States and eastern Asia. For coincident positive AO and negative PNA days, a large number of fires have been identified over northwestern North America and northern Eurasia. Spectral analyses demonstrate that weather anomalies related to AO and PNA lead fire danger by 10–20 days, and both modes are significantly correlated to PFIv2 over north America and most of Eurasia. Despite some drawbacks related to the fire danger methods currently applied (PFI and FWI), it is demonstrated that the influence of AO and PNA on potential environmental driven-fires can be anticipated, in some locations on almost 90% of days. Fire danger forecasts are urgently needed and the understanding of factors and conditions, which are able to modify the environmental susceptibility to fire development, are crucial for adequate management to reduce the harmful effects of fire. In this sense, our results reveal that a better prediction of the fire season can be achieved by advanced assessment of the PNA and AO behavior, and shed light on the need to investigate the impact of other modes of climate variability upon wildfire frequency and severity.