Fig. 4

Regression of detrended a precipitation and b PET onto the detrended SPEI-3 over SE China (unit: mm day⁻¹). Significant values exceeding the 0.1 and 0.05 significance levels are marked by gray and black dots, respectively. Contributions of c precipitation and d PET to the April SPEI-3 (unit: %) at interannual time scale are also shown