基于SPEI的粤西近50 a干旱特征分析

李家良, 彭丽英, 刘祖任, 余绍荣, 梁家杰

Drought characteristics in western Guangdong over the past 50 years based on SPEI

LI Jialiang, PENG Liying, LIU Zuren, YU Shaorong, LIANG Jiajie

图5 1973—2022年粤西年SPEI与不同环流指数交叉小波变换周期 （黑色细实线为小波边界效应影响锥，粗黑实线表示通过置信水平为95%的红噪声检验；箭头表示位相关系：←表示两个序列变化呈负位相关系，→表示两个序列变化呈正位相关系，↓表示位相超前90°，↑表示位相滞后90°；色标表示交叉小波变换周期）

Fig.5 The cross wavelet transform period between annual SPEI and different circulation indices in western Guangdong during 1973-2022 (The black thin solid line represents the influence cone of wavelet boundary effect, the thick black solid line represents the red noise test with a confidence level of 95%; the arrow represents the phase relationship: ← represents the negative phase relationship between the two sequence changes, → represents the positive phase relationship between the two sequence changes, ↓ represents the phase leading by 90°, ↑ represents the phase lagging by 90°; the color code represents the period of the cross wavelet transform)