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

Abstract

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.

Swamp Wetlands in Degraded Permafrost Areas Release Large Amounts of Methane and May Promote Wildfires through Friction Electrification

“…In addition, lightning played a key role in the recent forest fires recorded in northern North America near the Arctic tree line. The increased impact of lightning is considered when assessing lightning-wildfire feedbacks [95][96][97]. A recent study pointed out that the lightning frequency in the Arctic (Siberia) is greater than it was a decade ago and that this frequency may double soon.…”

The role of long-term trends and internal variability in altering fire weather conditions in the western United States

“…In addition to background climate change, re-favored conditions such as changes in heat, drought, vegetation, and water resources, have been linked to modes of internal climate variability, including oceanic conditions tied to the El Niño-Southern Oscillation (ENSO) [49][50][51][52] , Paci c Decadal Oscillation (PDO), and Atlantic Multidecadal Variability (AMV) [53][54][55] , and atmospheric conditions associated with the Paci c-North American Pattern (PNA) 56 , and Arctic Oscillation (AO) 57 . Other possible contributing factors include reduced Arctic sea ice 58 , synoptic-scale phenomena such as lightning ignition 59,60 , hurricanes 61 , wind gusts 62 , and blocking events 63,64 .…”

Tropical influences on European summer climate variability

“…Mean sea level pressure (MSLP) patterns also play a role. In North America, summer temperatures are related to the Pacific-North America pattern (PNA) and the Arctic oscillation (Justino et al 2022), albeit with weaker links than in winter (Manthos et al 2022). In Europe, summer temperature and precipitation are related to the two leading modes of variability in MSLP over the North Atlantic sector, the Summer North Atlantic Oscillation (SNAO, Folland et al 2009) and the Summer East Atlantic Pattern (EAP, Barnston and Livezey 1987), with associated impacts on surface temperature over Europe (Cassou et al 2005).…”