不同时间尺度下气象干旱向水文干旱传播过程

Propagation Process of Meteorological Drought to Hydrological Drought in Different Time Scales

利用黔中地区1970—2016年逐月降水以及径流计算标准化降水指数(SPI)和标准化径流指数(SSI),分别表征气象、水文干旱,采用游程理论等方法分析了该地区不同时间尺度的气象水文干旱动态变化特征,并以交叉关联函数以及干旱传播阈值等方法探求不同时间尺度上气象干旱向水文干旱传播时间。结果表明:(1)黔中地区气象水文干旱化态势以上升趋势为主,重度和极端干旱发生的频数增加,长时间尺度上,气象与水文干旱特征具有一定的同步性。(2)不同季节上干旱传播时间(PT)不同,春季PTs在1~5个月,夏季PTs在1~3个月,秋季PTs在1~4个月,冬季PTs为1~3个月。(3)在地形地貌影响下,不同时间尺度的PTs不同。3个月时间尺度下,阳长、高车和麦翁的PTs为1.36,2.00,1.58个月;6个月时间尺度下,PTs为2.75,2.55,3.00个月;12个月时间尺度下,PTs为3.33,2.56,7.17个月。

The standardized precipitation index(SPI)and the standardized runoff index(SSI)were calculated using the monthly precipitation and runoff from 1970 to 2016 in central Guizhou,that characterize meteorological and hydrological droughts respectively.The dynamic characteristics of meteorological and hydrological drought in different time scales were analyzed by using run theory,the propagation time of meteorological drought to hydrological drought on different time scales was explored by using cross correlation function and drought propagation threshold.The results showed that:(1)In the past 47 years,the trend of meteorological and hydrological aridity in central Guizhou has been on the rise.The frequency of severe and extreme drought increased,and the characteristics of meteorological and hydrological drought were synchronous in a long time scale;(2)Drought propagation time(PT)was different in different seasons.PTs in spring were 1 to 5 months,PTs in summer were 1 to 3 months,PTs in autumn were 1 to 4 months,and PTs in winter were 1 to 3 months.(3)Under the influence of topography and geomorphology,the PTs of different time scales were different.On the 3-month time scale,the PTs of Yangchang,Gaoche,and Maiweng were 1.36,2.00,and 1.58 months;on the 6-month time scale,the PTs were 2.75,2.55,and 3.00 months;on the 12-month time scale,PTs were 3.33,2.56,and 7.17 months.