Fig. 1: Seasonal relationship between Law Dome summer sea-salt (LDsss) and Australian fire weather over November to February (NDJF).
From: Australia’s 2019/20 Black Summer fire weather exceptionally rare over the last 2000 years
a Map of the study region showing the location of Law Dome (blue triangle) and focus region of southeast Australia (red eclipse). b Odd ratio of the probability of occurrence of high fire weather hazard days (Forest Fire Danger Index > 90th percentile (1951–2016)) in late spring-summer during 22 low-sea salt aerosol concentration seasons (LDsss lower tercile <33% between 1951–2016) vs 45 non-low-sea salt aerosol concentration seasons in the ice core. c Pearson correlation between LDsss and Australian seasonal average (NDJF) Forest Fire Danger Index (FFDI) between 1950/51 − 2015/16. Dots indicate significance accounting for temporal and spatial autocorrelation (i.e. false discovery rate). The Black area outline indicates the region used for area average calculation in d, and is based on the confluence of the region affected by the Black Summer fires and the region where LDsss has a strong connection to Australian FFDI. d Timeseries comparison between area-averaged FFDI over southeast Australia (area marked on b/c) and inverted LDsss concentration (μEq L-1). The correlation and regression score between LDsss and area average FFDI over two time periods are shown; 1951–2016 and 1960–1990.
