贵州省干旱变化特征及其与大气环流关系

根据贵州省 1960- 2018 年 17 个气象站点的月降水量和平均气温数据, 采用标准化降水蒸散指数( SPEI) 定量表征干旱, 利用 M2K 趋势检验及 R/ S 法分析了贵州省近59 年干旱变化趋势及未来变化趋势的持续性, 采用连续小波变换和交叉小波变换分析贵州省 SPEI 和 4 种环流因子( MEI、NAO、AO、PDO ) 的振荡周期特征及其之间在时频域中的共同特征和相关关系。结果表明: 贵州省月、春、秋和年 SPEI 序列呈显著下降趋势( 通过显著性检验) , 即贵州省春旱和秋旱逐步加剧, 其中秋季下降速率最大为- 0 108/ ( 10a) , 而夏旱和冬旱的增加趋势未通过显著性检验;未来春旱和秋旱将保持上升趋势, 干旱程度可能愈发严重, 而未来夏旱和冬旱强度存在减弱的可能性; 干旱事件具有显著的 16~ 48 个月的年际振荡周期特征, 干旱和四种环流因子的年际共振周期为 24~ 110 个月, 年代际共振周期为 128~ 250 个月, SPEI 与 NAO、AO 之间呈滞后的正相关关系; 整体上, MEI 主要影响贵州省干旱较短的年际周期变化, PDO 和 AO 主要影响干旱较长的年代际周期变化, 而 NAO 的影响较小。 Standardized Precipitation Evapotranspiration Index ( SPEI ) was used to quantitatively characterize the drought conditions based on monthly precipitation and mean temperature data obtained from 17 meteorological stations from 196022018 in Guizhou Province. The M2K tr end test and R/ S analysis were used to analyze the drought trend in Guizhou Province in the past 59 years. The continuous wavelet transform and cross wavelet transform were used to analyze the characteristics of oscillation period of SPEI and four circulation factors ( M EI, N AO , AO , PDO ) , their common char acteristics and correlation in time and frequency domain. The results showed that the monthly, spring, autumn and annual SPEI series showed a significant downward trend and the decline - 0. 108/ ( 10a) fo r autumn SPEI compared to other series, which indicated that spring and autumn drought gradually intensify in Guizhou Province. The spring and autumn drought may upward in future and the intensity may become more severe, while the intensity of summer and winter drought expressed a weakened possibility . The SPEI had 16-48 months inter-annual oscillation period, and there was a common patterns of 24-110 month at inter-annual and 128-250 month at inter-decadal oscillation circles between SPEI and M EI, N A O, AO , P DO, while a lag positive correlation existed between SPEI and N AO , A O . O verall, M EI mainly affect ed the int er-annual cycle variation o f drought, while PDO and AO mainly affected the longer inter-decadal cycle variation of drought.