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以洞庭湖区1950-2009年的灾情?雨情和水情等资料为依据,运用灾害系统理论与方法,分析了湖区农业水旱灾害的演变特征及其影响因素。结果表明:在水旱灾害时间序列中,其演变特征表现为:⑴具有明显的频发性,不同等级的旱灾在1950-1999年间为间歇发生,但2000年以来为连年发生,不同等级的水灾年年发生;⑵水旱承灾体受灾率?成灾率异常指数的演变具有高位波动性,其中以水灾波动幅度最大;⑶水旱灾害损失演变的总体趋势表现为:水灾损失减少,旱灾损失稍有增加;⑷三峡水库运行以来,毁灭性的洪溃决堤灾害得到有效控制,但涝渍灾害仍然频发,夏秋连旱灾害年年发生。水旱灾害的这些演变特征即是洞庭湖流域降水量年际、年内分配不均,河?湖?库蓄水量年际年内变化大,以及湖区各个阶段对防洪?排涝?抗旱等水利设施建设投资力度的差异等因素综合作用的结果。
Based on the data from the flood and rainfall conditions in the Dongting Lake area from 1950 to 2009 and using the theories and methods of disaster systems, the evolution characteristics of agricultural floods and droughts in the lake area and their influencing factors were analyzed. The results show that in the time series of floods and droughts, the evolvement characteristics are as follows: (1) With obvious frequency and frequency, different grades of droughts occurred intermittently during 1950-1999, but they occurred year after year with different levels of floods (2) The disaster-affected area has a high volatility, of which the flood is the most volatile. (3) The general trend of flood and drought disaster loss is as follows: the loss of flood damage and the loss of drought A slight increase; (4) Since the Three Gorges Reservoir operation, the devastating flood collapse dike disaster has been effectively controlled, but the waterlogging disasters are still frequent, summer and autumn even the drought disasters occur annually. These evolvement characteristics of floods and droughts are the annual precipitation of Dongting Lake basin, the uneven distribution during the year, the great changes of water storage capacity of rivers and lakes in interannual years, and the flood control and drainage, drought and other water conservancy facilities construction in all stages of the lake area The intensity of investment and other factors as a combined result.