排序方式： 共有4条查询结果，搜索用时 15 毫秒
1
1.
三峡建库后东洞庭湖适宜生态水位需求分析 总被引：1，自引：0，他引：1
三峡水库的修建改变了水库下游的水沙条件,影响了洞庭湖湖区的生态平衡,进而引发相关生态问题本文以城陵矶站水位代表东洞庭湖水位,基于其1953 2018年的逐日水位资料,采用滑动t检验法对年平均水位序列进行突变检验,发现因强人类活动导致城陵矶水位发生突变的时间为2004年,考虑为三峡蓄水的影响借鉴IHA(Indicators of Hydrological Alteration,水文变化指标)及RVA(Range of Variability Approach,变化范围法)方法提出了一种同时考虑年内月平均水位过程、水位波动范围、高低水位发生情况以及水位涨落情况的适宜生态水位计算指标体系,能够直观和全面地描述生态系统健康发展对水位的要求,包括1 12月水位分别为:17.07～18.34、17.15～18.89、17.65～22.23、20.25～22.15、22.85～24.90、24.31～26.44、26.88～29.16、25.79～28.32、25.12～27.56、23.59～25.88、20.65～22.81、18.58～19.88 m;年最低水位:16.21～17.86 m,发生时间为第16～51天(年积日);年最高水位:28.54～31.48 m,发生时间为第187～211天(年积日);高水位平均持续时间为32.62～81.32 d/次,低水位平均持续时间为52.13～107.65 d/次;涨水次数为21.9～26.45次,涨水速率为0.17～0.21 m/d;落水次数为23.17～27.6次,落水速率为0.12～0.14 m/d基于上述结果分析三峡建库后城陵矶水位发现,其在1、2月月平均水位分别较适宜生态水位需求高0.83、0.27 m; 10月月平均水位较需求低0.83 m;年最低水位高出需求0.39 m,发生时间先于需求6天;涨水次数高于阈值要求4次,涨水速率低于阈值要求0.01 m/d;落水次数高于阈值要求2次研究成果可为三峡及上游梯级水库群联合调度提供依据. 相似文献
2.
Most natural disasters are caused by water‐/climate‐related hazards, such as floods, droughts, typhoons, and landslides. In the last few years, great attention has been paid to climate change, and especially the impact of climate change on water resources and the natural disasters that have been an important issue in many countries. As climate change increases the frequency and intensity of extreme rainfall, the number of water‐related disasters is expected to rise. In this regard, this study intends to analyse the changes in extreme weather events and the associated flow regime in both the past and the future. Given trend analysis, spatially coherent and statistically significant changes in the extreme events of temperature and rainfall were identified. A weather generator based on the non‐stationary Markov chain model was applied to produce a daily climate change scenario for the Han River basin for a period of 2001–2090. The weather generator mainly utilizes the climate change SRES A2 scenario driven by input from the regional climate model. Following this, the SLURP model, which is a semi‐distributed hydrological model, was applied to produce a long‐term daily runoff ensemble series. Finally, the indicator of hydrologic alteration was applied to carry out a quantitative analysis and assessment of the impact of climate change on runoff, the river flow regime, and the aquatic ecosystem. It was found that the runoff is expected to decrease in May and July, while no significant changes occur in June. In comparison with historical evidence, the runoff is expected to increase from August to April. A remarkable increase, which is about 40%, in runoff was identified in September. The amount of the minimum discharge over various durations tended to increase when compared to the present hydrological condition. A detailed comparison for discharge and its associated characteristics was discussed. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
3.
复杂环境下华南东江中上游流域筑坝导致的水文变异 总被引：5，自引：2，他引：3
采用可视化分析软件包XmdvTool来评价复杂环境下东江中上游流域(1952-2002)水文变异以克服常规RVA方法的限制,在分离了气候变化对水文变异影响后,结合RVA方法系统地研究了华南东江中上游流域由于筑坝等人类活动引起的河流水文变异时空演化规律.结果表明:(1)1952-2002间由筑坝导致的最显著的东江中上游流域水文变异是最小3d流量,低流量持续时间、1月平均流量和7月平均流量等3个IHA因子;(2)在河源和岭下两站水文变异9个IHA因子相关图中,1月和2月平均流量,1月平均流量和最小90d流量相关图中各存在一个较为明显的线性回归趋势,表明上述因子存在较明显的相关关系;(3)东江中上游综合水文变异强度由大至小分别为:河源、龙川和岭下.运用高维水文数据可视化分析技术结合RVA方法可有效用于天然河流水文变异时空变化研究,研究结果对于东江河流生态环境管理、生态恢复和水资源一体化管理具有重要意义,可为流域水文变异的理论与方法研究提供借鉴. 相似文献
4.
变动范围法(RVA)是国内外评价河流水文特征变化的重要方法,但其存在忽略水文年变化特征及中低度改变指标的缺陷。针对此问题,采用CRITIC法结合欧氏距离对传统RVA进行改进,并将改进方法用于黄河源区(唐乃亥水文站),分析黄河源区径流量的水文指标变化趋势和整体水文变异程度。研究结果表明:唐乃亥水文站在1990年时水文情势发生突变,突变后流量呈减少趋势;受干扰后的唐乃亥水文站2/3月份平均流量、年最小7/30/90d流量、年最大90d流量、高流量平均延时、流量平均减少率/增加率共9个指标为中度改变,其余指标为低度改变;黄河源区水文特征年改变度为41.36%,水文指标整体改变度为27.33%,水文情势整体改变度为57.39%,属于中度改变。 相似文献
1