Fig. 4: Contribution of sub-diurnal asymmetric warming to trends in saturated vapor pressure (SVP), relative humidity (RH), and vapor pressure deficit (VPD) from 1980 to 2023.
From: Sub-diurnal asymmetric warming has amplified atmospheric dryness since the 1980s
a–c Variations and changes in the annual average model-fitted (subscript fitted) VPD (a), SVP (b), and RH (c), and the contributions of diurnal temperature range (subscript DTR), daily mean temperature (subscript Tmean), soil moisture (subscript SM), daily maximum temperature (subscript Tmax) and daily minimum temperature (subscript Tmin) to the variations and changes over land. The model-fitted values are anomalies calculated by subtracting the mean values for the control period (1980–1982). The dashed lines show the linear trends obtained from linear regressions. d, f and g Spatial distribution of trends in VPDDTR (d), RHTmax (f), and RHTmin (g). Insets show boxplots of trends across observation stations (solid boxes) and ERA5-Land grid points (hollow boxes). Pie charts show the percentage of land area with significantly (p < 0.05) positive (red), weak positive (light red), weak negative (light blue), and significantly negative (blue) trends, based on ERA5-Land data. e, Spatial distribution of differences between trends in SVPTmax and SVPTmin. Insets show boxplots of differences across observation stations (solid boxes) and ERA5-Land grid points (hollow boxes). Pie chart show the percentage of land area with positive (red) and negative (blue) differences based on ERA5-Land data. In all boxplots, the height of each box represents the interquartile range of trends or differences across different stations or grid points, with the thick black line indicating the median, and the edges denoting the first and third quartiles. Whiskers extend to the 2.5th and 97.5th percentiles.
