关中地区气象水文综合干旱指数及干旱时空特征

根据陕西关中地区22个气象站和3个水文站1961—2016年的气象水文资料,计算了不同时间尺度的标准化降水蒸散发指数(SPEI)与径流干旱指数(SDI),运用Gumbel Copula函数构建了气象水文综合干旱指数(MHDI),探讨了MHDI的适用性,并分析了气象水文综合干旱时空分布特征。结果表明:MHDI综合了SPEI与SDI的优点,可同时表征月尺度和年尺度的气象干旱与水文干旱;关中地区MHDI序列值有明显的下降趋势,干旱情况逐年加剧;MDHI序列存在变异,年尺度变异点集中于1986年和1990年;年尺度的序列值主周期多集中在20～22 a;泾河流域干旱发生频率最低,为19.11%,北洛河流域干旱发生频率最高,为47.97%,渭河流域干旱发生频率介于两者之间,为26.42%。

Meteorology-hydrology drought index and spatial and temporal characteristics of drought in Guanzhong area

Based on the meteorological and hydrological data of 22 meteorological stations and 3 hydrological stations in Guanzhong area of Shaanxi Province from 1961 to 2016, the standardized precipitation evapotranspiration index(SPEI)and streamflow drought index(SDI)at different time scales were calculated. The Gumbel Copula function was used to construct the meteorology-hydrology drought index(MHDI), and the applicability of MHDI was discussed. The spatial and temporal distribution characteristics of meteorological and hydrological comprehensive drought were analyzed. The results show that MHDI combines the advantages of SPEI and SDI, and can characterize meteorological drought and hydrological drought on both monthly and annual scales. The MHDI sequence values in Guanzhong area show a significant downward trend, and the drought situation increases year by year. There are variations in MDHI sequence, and anual scale variation points are concentrated in 1986 and 1990. The main period of annual MHDI sequence values is mostly concentrated in 20-22 years. The frequency of drought is the lowest in Jinghe River Basin(19. 11%), the highest in Beiluo River Basin(47. 97%), and 26. 42% in Weihe River Basin.