陕西省水资源供求指数和综合干旱指数及其时空分布

识别区域的干旱时空特征对于防旱抗旱具有重要指导意义。论文采用两种方法研究了陕西省干旱时空分布特征并比较了两种方法在应用中的优缺点：其一,考虑社会经济因素对干旱的影响,采用基于水资源供水和需水平衡的陕西省社会经济干旱指标（水资源供求指数）;其二,结合SPI、PDSI和SPEI的特点,运用模糊综合法建立了综合干旱指数。结果表明：陕西省干旱发生频率很高,南北多发生轻微干旱,中部多发生中重度干旱。陕西省干旱在空间上分布差异大,两种方法均表明咸阳、西安、渭南和铜川地区旱情最为严重。在水资源量存在巨大差异的地区,如商洛与榆林,仅用一种类型的干旱指标无法全面体现实际情况,两种方法的结论存在差异：综合干旱指数表明榆林干旱较重,但供求指数为轻旱;商洛供水可满足需水,但综合干旱指数为轻旱。气象干旱指数,在水资源短缺的地区或自然生态系统中,结果更贴近于实际;社会经济干旱指数——水资源供求指数,更适宜用于水资源极其丰富且供水能力强的地区。

The Spatial and Temporal Distribution of Drought in Shaanxi Province

At present, most of the drought researches are based on a single meteorological or hydrologic drought index which can not reflect the drought situation or social contradiction of supply and demand of water comprehensively. This paper studied the spatial and temporal distribution of drought in Shaanxi Province based on the method taking the social economic factors of drought into account. The natural meteorological factors are also taking into consideration. We established comprehensive drought evaluation index of Shaanxi Province with fuzzy comprehensive decision process on basis of meteorological data from 19 meteorological stations in Shaanxi from 1960 to 2013. The results showed that the spatial distribution of drought in Shaanxi Province is heterogeneous, the drought in the central Shaanxi (DI value is about 3) is more serious than in northern Shaanxi, and there is no drought in south Shaanxi at the same time where water resources are abundant. Drought occurrence frequency in Shaanxi Province is very high. The medium drought phenomenon mostly existed in the north and south (frequency approached to 80%-99.99%). The severe droughts occurred in the central Shaanxi more often (frequency approached to 79%). The method of water supply and demand evaluation considered the influence of social economy and the actual supply and demand contradiction. And the comprehensive meteorological drought index considered the effects of meteorological factors. The results of the two methods are basically identical, but only one type of drought index can not reflect the overall actual situation when there exists great difference of water quantity in different areas. In water shortage regions, the results of fuzzy comprehensive drought index are closer to the fact. In regions where water resource is extremely rich and water supply ability is strong, the results of water supply and demand method are closer to the fact. And in economic developed areas, social economy drought index is suggested. When doing researches of drought, it shall give full consideration to the natural meteorological factors and actual water supply ability.