Fig. 2: Southern Ocean synoptic weather conditions associated with elevated fire weather hazard over southeast Australia.
From: Australia’s 2019/20 Black Summer fire weather exceptionally rare over the last 2000 years
Mean NDJF frequency of SOM nodes (defined in Udy et al.46) over 1979-2018 in brackets - e.g. SOM1 (10.6%) (i) 500hpa geopotential height anomalies of SOM nodes associated with elevated fire weather over southeast Australia (data: ERA-Interim). Positive height anomalies are shown in red with solid contours and represent regions of anticyclonic ridging into mid-high latitudes. Negative height anomalies are shown in blue with dotted contours and represent regions of low pressure extending further north than usual. Example fire disasters associated with synoptic conditions listed. LD = Law Dome ice core location, GAB = Great Australian Bight, TS = Tasman Sea. (ii) Changes in the likelihood of high fire danger days (FFDI > 90th percentile 1951–2016) during the occurrence of each SOM node. p-value < 0.05 was used for significance and non-significant results were blank. (iii) Seasonal (November - February) daily FFDI anomaly for each SOM node. Refer to Supplementary material for odds ratio (Supplementary Fig. 5) and FFDI anomaly (Supplementary Fig. 6) composites for the remaining SOM nodes.
