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降雨是诱发洪涝灾害的主要因素,降雨特性的研究对流域洪涝风险防范具有重要意义。采用距平分析、Mann-Kendall检验和重标极差R/S分形分析等方法,对1951年来洪泽湖流域年面雨量的变化特性和趋势进行分析。结果表明:在气候变暖的影响下,近58a来流域年雨量波动幅度较大,面雨量总体呈现增加的趋势,但增加趋势不显著,面雨量异常时往往导致洪涝发生。在变化阶段上,年面雨量经历了1950s到1970s的年代际减小和1980s以来持续增加的两个阶段,且年雨量在1965年和2003年左右出现降雨突变异常并导致严重洪涝灾害。Hurst分形指数为0.538,表明未来流域年面雨量具有持续性和长程记忆效应,雨量仍然呈增加趋势,并具较大随机性,说明未来降雨变化具有较大的不确定性特征。洪泽湖流域降水变化特性和未来变化趋势的规律认识对流域风险防范具有重要意义。
Rainfall is the main factor to induce flood disaster. The study of rainfall characteristics is of great importance to the prevention of flood risk in the basin. By means of anomaly analysis, Mann-Kendall test and R / S fractal analysis, the change characteristics and trend of annual rainfall in Hongze Lake Basin in 1951 were analyzed. The results show that under the influence of climate warming, the annual rainfall in the past 58 years fluctuated greatly, and the surface rainfall generally showed an increasing trend, but the increasing trend was not significant. Floods often occurred when the surface rainfall was abnormal. In the changing stage, the annual rainfall has experienced two stages, the decadal decay from 1950s to 1970s and the continuous increase since 1980s, and the annual rainfall anomalies in 1965 and around 2003 caused serious floods and floods. The Hurst fractal index is 0.538, which indicates that the surface rainfall in the future has persistent and long-term memory effect. Rainfall is still increasing with large randomness, which shows that the rainfall in the future is characterized by large uncertainties. The understanding of the regularity of precipitation change and future trend of the Hongzehu watershed is of great significance to prevent the risk in the watershed.