Table S1.

Pearson’s correlation coefficients between standardized fuel aridity metrics and log-10 area burned (1984–2015), and linear change in in the standardized duel aridity metrics during 1979–2015

MetricgridMETNo ACC gridMETERA–INo ACC ERA–INN1No ACC NN1
Interannual correlation with log–10 of area burned
 PDSI–0.76**–0.71**–0.74**–0.72**–0.72**–0.67**
 FWI0.80**0.71**0.87**0.86**0.75**0.69**
 ERC0.87**0.85**0.86**0.85**0.75**0.71**
 FFDI0.83**0.74**0.86**0.85**0.76**0.64**
 ETo0.81**0.65**0.82**0.73**0.71**0.54**
 CWD0.87**0.81**0.87**0.85**0.78**0.72**
 KBDI0.80**0.74**0.79**0.73**0.73**0.60**
 VPD0.87**0.77**0.83**0.81**0.75**0.60**
 MEAN0.87**0.79**0.87**0.85**0.80**0.70**
Linear trend in standardized fuel aridity metric per 37 years
 PDSI–1.12*–0.75–1.28**–1.03**–0.86**–0.59*
 FWI0.79*0.251.64**1.15**0.91**0.46*
 ERC1.30**0.93**1.61**1.34**0.79**0.52*
 FFDI1.04*0.352.03**1.18**0.79*0.10
 ETo1.45**0.271.81**0.86*1.07**0.16
 CWD1.30**0.701.63**1.22**0.92*0.47
 KBDI0.94**0.491.63**0.72*0.80**0.09
 VPD1.73**0.582.24**1.26**1.30**0.23
 MEAN1.21**0.541.73**1.10**0.93**0.33
  • Units of the trends are SDs per 37 y, as in Fig. 3. Columns labeled as “No ACC” indicate that these variables have been recalculated after subtraction of the CMIP5 ensemble-mean trends in temperature and vapor pressure. Correlations and trends are shown using the gridded meteorological dataset (gridMET) (50), ERA-INTERIM (ERA-I), and NCEP–NCAR (NN1). Asterisks indicate significance at the (*) 95% and (**) 99% levels. Significance was evaluated using a two-tailed test for correlations and a single-tailed test for trends.