近100年关中地区干旱灾害的时空变化分析

Analysis of spacial-temporal change of drought disaster in Guanzhong area for recent 100 years

通过历史文献资料的收集和整理,对1900-2000年关中地区干旱灾害的变化阶段、空间变化、等级分布、变化趋势进行了研究。结果表明:关中地区近100 a共发生干旱灾害53次,平均每1.9 a发生一次。关中地区近100 a来发生的旱灾等级以中度旱灾为主,共发生23次,占旱灾总数的43.4%;其次为轻度旱灾和大旱灾,分别发生14和13次,占旱灾总数的26.4%和24.5%;特大旱灾较少,共发生3次,占旱灾总数的5.7%。关中地区近100 a来干旱灾害有明显的地区和季节差异,中东部为旱灾的高发区,其中渭南地区干旱灾害的发生次数最多,远远高于其他几个地区;旱灾以春旱和夏旱为主,分别占总数的11.3%和20%。关中地区近100 a干旱灾害发生的趋势为先下降后上升的趋势,从20世纪初至70年代干旱灾害的发生次数呈下降趋势,70年代至2000年略有上升。关中地区的气候类型和地理位置及人类活动是该区干旱灾害发生的主要原因。

According to the historical materials,the paper studied the variation stages,special variation,grades and trends of drought disaster in Guanzhong region from 1900 to 2000. The results showed that drought disasters accurred 53 times and averagely occurred one time per 1. 9 year. The frequency of drought disaster increased continuely. The drought disasters in Guanzhong area are dominated by the moderate ones which was 23 times and occupied 43. 4% of the total; follow was the Light drought of 14 times which occupied 26. 4% and the big drought disaster of 13 which occupied 25%; the greatest drought disaster occurred 3 times and occupied 6% of the total. The regional and seasonal differences of drought disaster in the Guanzhong area for recent 100 years was obvious. The drought disaster mainly accurred in middle and west area of Guanzhong. The number of drought disaster in Weinan region was the most and more than that in other regions; the drought disaster mainly occurred in summer and spring,and occupied20% and 11. 3% of tatal disasters. The trend of drought disaster was first decrease and then increase in Guanzhong region for recent 100 years. The drougth disaster gradually reduced from the 20 th century to the 1970 s,but increased little more from 1970 s to 2000. The climate type,geography location and human activity in Guanzhong region are the main reasons for the happening of drought disaster.