Fig. 5: Land-atmosphere coupling strength (π) from ERA5-land reanalysis data.
From: Anthropogenic warming has exacerbated droughts in southern Europe since the 1850s
Linear trends of June-August land-atmosphere coupling strength (π) over the period 1959–2018 CE (a). The inter-annual variation of June–August land-atmosphere coupling strength over the period 1959–2018 CE for central (light red lines) and southern Europe (light blue lines), trend lines are estimated using the non-parametric LOESS regression technique, and shading represents the 95% confidence intervals of the estimated trends (b). Composite anomaly map of summer coupling strength for the 8 identified dry years of southern Europe (c), and the 10 identified dry years of both southern and central Europe (d). The coupling strength is calculated based on the ERA5-Land reanalysis daily data set with 0.1° latitude × 0.1° longitude spatial resolution. Black dots in a, c, and d mark the grids where trends are significant at the 95% confidence level. The Z scores in b indicate the standardized values of land-atmosphere coupling strength (π), which is calculated to facilitate the comparisons.
