Fig. 1: Long-term drying trends over SA. | npj Climate and Atmospheric Science

Fig. 1: Long-term drying trends over SA.

From: Combined large-scale tropical and subtropical forcing on the severe 2019–2022 drought in South America

Fig. 1

a Spatial distribution over SA of soil moisture trends (\({m}^{3}/{m}^{3}\) per decade) over the 1990–2022 period. The black dots depict regions with statistically significant trends at a 5% level, according to the non-parametric Mann–Kendall two-tailed test. The limits of the Amazon basin, La Plata Basin and the Pantanal biome are marked by the purple, blue and turquoise lines, respectively. The red box delimitates the region of interest covering CESA. b Bivariate Gaussian probability distribution functions of mean annual surface temperatures (°C) and daily accumulated precipitation levels (mm) averaged over CESA, for the 1959–1989 (blue ellipses) and the 1990–2022 periods (orange ellipses). The gray ellipses show the 95% level of the probability distribution. c Time series (1951–2022) of mean annual soil moisture levels, spatially averaged over CESA (green and yellow lines, left y-axis), and of the time accumulated soil moisture anomalies regarding the climatological period of 1981–2010 (black line, right y-axis). The dash green and yellow lines result from a regression model with two segmented (i.e., piecewise) linear relationships separated by a break point (obtained from an iterative process described in Supplementary Material) highlighted by the filled black dot. The respective trend values are shown in the bottom part of the panel.

Back to article page