Fig. 3

a Spatial distributions of the linear trend of April SPEI-3 (unit: decade⁻¹). Significant values exceeding the 0.1 and 0.05 significance levels are marked by gray and black dots, respectively; b Time series of FMA-accumulated precipitation averaged over SE China (unit: mm day⁻¹). Black solid line indicates the linear trend of precipitation; c is the same as b, but for April SPEI-3 (black line) and SPI-3 (blue line). Black and blue dashed lines indicate the linear trends in April SPEI-3 and SPI-3, respectively