基于SPEI和SPI指数的太原多尺度干旱特征与气候指数的关系

干旱是太原地区发生最频繁的自然灾害之一,出现的次数多、持续的时间长,对国民经济特别是农业生产造成了严重的影响.随着全球气候变暖、极端天气出现得越发频繁,太原干旱发生的频率和危害程度均呈上升趋势.基于1951-2012年月平均降水和气温资料,引入新的干旱指标：标准化降水蒸散指数（SPEI）,应用SPEI和SPI（标准化降水指数,简称：SPI）定量描述太原地区的62年来的干湿状况;基于月尺度SPEI和SPI指数,对太原月季尺度干旱变化做了分析,并利用交叉小波变换（XWT）探讨了干旱与大尺度气候因子之间的关系.结果表明：基于降水和蒸散的SPEI可以更灵活地反映月季干旱变化特征;交叉小波变换分析表明,太原地区的干旱与4个大尺度因子都具有6-12 a年代际主共振周期,在1980s都存在较好的相关性.SPEI和SPI与NAO通过显著性检验的6-12 a共振周期主要表在1985-2000年,序列在此频段上表现出一定的正位相共振关系;SPEI和SPI与WP在1955-1960年和1990-2000年分别表现出2-3 a和4-8 a显著的共振周期,存在明显的滞后相关,在1970-1990年具有10-16 a正位相显著共振关系.SPEI与PDO在1986-2000年之间存在4-6、8-14 a两个显著的共振周期,各自表现出负、正位相共振关系,在1955-1960年存在2-3 a共振周期,在此频段上SPEI显著滞后于PDO.与SPEI相比,SPI与PDO的相关性较弱,仅在1955-1960、1986-2000年出现了弱的共振关系.SPEI和SPI与PNA在1983-1995年表现出4-7 a的显著共振关系,反映了SPEI和SPI显著滞后于PNA.

Multiscale Characteristics of Drought Based on SPEI and SPI in Association with Climate Index in Taiyuan

Drought is one of the most frequent natural disasters occurred in Taiyuan on long duration, especially to the nationaleconomy caused serious influence of agricultural production. With the global warming, more frequent extreme weather occurs,Drought frequency and damage are on the rise in Taiyuan. Based on the Station data of average precipitation and temperature from1951 to 2012, SPEI, SPI index is used to quantitatively describe the Taiyuan drought in 62 years. Based on monthly scale SPEI, SPIindex to analyze the changes of Taiyuan drought, and discuss the relationship between drought and large-scale climate factors withthe cross-wavelet transform （XWT）. The results show that the SPEI based on precipitation and evapotranspiration can be moreflexible to reflect the characteristics of the drought changes; Cross wavelet transform analysis manifested a primary resonance cyclein 6-12 a between drought in Taiyuan and four large scale factors. A 6-12 a resonance cycle between SPEI, SPI and NAO wasthrough the test of significance in the 1985-2000, and with certain positive correlation; The relationship between SPEI, SPI and WPin 1955-1960, 1990-2000 and 1970-1990 respectively has been presented in 2-3, 4-8 and 10-16 a significant resonance cycle,and exist lag correlation in the former; The pertinence between SPEI and PDO in1986-2000 had been displayed by two significantresonance cycles of 4-6 and 8-14 a, which respectively showed that the relationship negative and positive phase. In 1955-1960, aresonance spectrum on SPEI significantly lagged behind the PDO. Compared with SPEI, the correlation between SPI and PDO isweak, the relationship of the weak resonance was only in 1955-1960 and 1960-2000 showed. Correlation between SPEI, SPI andPNA in 1983-1995 was emerged by significant resonance cycles of 4-7 a, which reflected the SPEI, SPI significantly lagged behindthe PNA.