Fig. 2: Relationship of burned area to fire weather and precipitation.
From: Global increase in wildfire potential from compound fire weather and drought
a Annual normalised burned area anomalies, \(({{{{\rm{BA}}}}}_{f})^{\prime} /{\sigma }_{{{{{\rm{BA}}}}}_{f}}\) (dashes indicate anomalies), for 2001–2019, averaged over dry antecedent years, defined as when \({P}_{a} \,<\, {\mu }_{{P}_{a}}-{\sigma }_{{P}_{a}}/2\). For most grid cells, five to seven years satisfy this threshold. b As in a but for years of heightened fire weather, defined as when \({{{{\rm{FWD}}}}}_{f} \,>\, {\mu }_{{{{{\rm{FWD}}}}}_{f}}+{\sigma }_{{{{{\rm{FWD}}}}}_{f}}/2\). c As in a but for wet antecedent years, \({P}_{a} \,>\, {\mu }_{{P}_{a}}+{\sigma }_{{P}_{a}}/2\). d Grid cells for which burned area anomalies increase when wet (blue; c) or dry (red; a) years compound with years of heightened fire weather (b). White indicates no increase in burned area from compound dry or wet years. There are typically only one to three of these compound years, but results are robust when computed with smaller departures from the mean e.g. using μ ± σ/4.
