Fig. 4: Temporal variations of summer vapor pressure deficit (VPD) over eastern Siberia during 1979–2021 and its linear trend patterns over 1979–2003 and 2004–2021 with and without Siberian blocking (SB) events.
From: Rapid summer Russian Arctic sea-ice loss enhances the risk of recent Eastern Siberian wildfires
a, b Normalized time series of summer (June–August, JJA) mean vapor pressure deficit (VPD, unit: hPa) averaged over eastern Siberia (90o–150oE, 60o–75oN) during 1979–2021 based on the daily-mean surface air temperature (SAT) from the ERA5 data, where the dashed blue (red) line represents the linear trends of VPD over 1979–2003 (2004–2021) with the slopes of 0.07 and 0.11 (1.70 and 1.35) standard deviations (STDs) per decade for the cases a with and b without Siberian blocking (SB) events (the case without SB events represents that blocking days from lag\(\,-\,10\) to 10 days are removed for each SB event and lag 0 denotes the peak day of SB). c–f Linear trend patterns of JJA-mean VPD (color shading, unit: hPa per decade) over c, d 1979–2003 and e, f 2004–2021 c, e with and d, f without SB events based on the daily-mean SAT, where the dotted region represents that the trends are statistically significant (p < 0.05) for the Mann–Kendall test.
