图4. 1971—2020年广东省年尺度SPEI的EOF分解前3个模态空间分布(a、c、d)及第1模态的时间系数(b)
Fig.4. Spatial distribution of the first three modes (a, c, d) and the time coefficient of the first mode (b) of EOF decomposition of annual scale SPEI in Guangdong Province during 1971-2020