在评价河流水文情势变化特征时,传统水文改变指标法(indicators of hydrologic alteration,IHA)存在的指标间相关性高和数据冗余问题会造成整体评价偏差。对汉江下游流域的河流水文情势评价时,考虑到汉江流域干支流日均流量及取水调水...在评价河流水文情势变化特征时,传统水文改变指标法(indicators of hydrologic alteration,IHA)存在的指标间相关性高和数据冗余问题会造成整体评价偏差。对汉江下游流域的河流水文情势评价时,考虑到汉江流域干支流日均流量及取水调水工程等的影响,分别选择汉江干流上的3个水文站及支流流域的3个水文站点,采用主成分分析法对6个水文站IHA指标进行优选,再利用相关性分析结果进一步筛选,优选出适用于评价汉江下游流域水文情势的13个代表性指标,分别为2月流量、4月流量、7月流量、10月流量、12月流量、基流指数、最低流量出现日期、最高流量出现日期、低流量脉冲次数、高流量持续时间、日均流量增加率、日平均流量减少率和日均流量反转数。结果表明:6个水文站的代表性指标间相关性均大幅降低,13个代表性指标间的相关系数不超过0.3的占比约70%;经变化范围评价法(range of variability approach,RVA)验证,IHA指标与优选出的代表性指标对汉江下游流域整体水文改变度评价结果的差值均小于7.5个百分点,表明其能够对汉江下游流域提供较为全面合理的水文情势变化评价。展开更多
Palaeoflood hydrology study is a leading subject in global change study. Through field investigation in the upper reaches of Hanjiang River, palaeoflood slackwater deposits (SWD) were found in the bedrock gorges of ...Palaeoflood hydrology study is a leading subject in global change study. Through field investigation in the upper reaches of Hanjiang River, palaeoflood slackwater deposits (SWD) were found in the bedrock gorges of the Yunxi reach. The results of field observation, laboratory analysis including particle-size distribution and magnetic susceptibility, and com- parison with modern flood deposits, the SWD were identified as the most typical Holocene palaeoflood deposits of the Hanjiang River. By using stratig;aphic correlation and OSL dating method, the palaeoflood event was dated to be 3200-2800 a BP at the turn from the middle to late Holocene. According to the palaeoflood peak stage and hydraulic parameters, the peak discharges of the palaeoflood were reconstructed as 48,830-51,710 m3/s by using the slope-area method. At same time, the flood peak discharges of 1983, 2005 and 2010 severe floods were reconstructed with the same method and hydraulic parameters in the same cross section. The error between the reconstructed and gauged discharges was 1.99%-4.21%. This showed that the reconstructed palaeoflood peak discharges were reliable. The flood peak discharge-frequency relationship at 10,000-year time scale was established by a com- bination of the gauged flood, historical flood and palaeoflood hydrological data. These results are very important for hydraulic engineering and flood mitigation on the Hanjiang River.展开更多
以秦岭南北的汉江上游、渭河为例,对比分析了万年以来洪水发生的时间、流量的差异,并探讨了气候变化与洪水发生的联系。结果表明:在长时间尺度上,秦岭南北的汉江上游、渭河均有古洪水事件的沉积记录,汉江上游的洪水流量远大于渭河流域...以秦岭南北的汉江上游、渭河为例,对比分析了万年以来洪水发生的时间、流量的差异,并探讨了气候变化与洪水发生的联系。结果表明:在长时间尺度上,秦岭南北的汉江上游、渭河均有古洪水事件的沉积记录,汉江上游的洪水流量远大于渭河流域的洪水流量,洪水发生时间主要集中在4 200~4 000 a BP和3 200~3 000 a BP这两个时间段内;对季风气候变化分析表明,4 200~4 000 a BP和3 200~3 000 a BP是季风突变气候恶化的两个转折期,气候突变使得秦岭南北河流在这个时间段均有古洪水事件记录,但因测年分辨率的限制,似乎秦岭南北洪水发生时间具有一致性。在短时间尺度上,对秦岭南北实测洪水分析发现,虽然大多数年份秦岭南北没有洪水同时发生,但在个别年份内秦岭南北还是有洪水同时发生情况;从华西秋雨角度分析表明,秦岭南北的汉江上游、渭河处于华西秋雨核心区,但因多种因素的影响,在多数情况下秦岭南北洪水发生的时间并不都是完全相同。研究成果有助于从水文学角度在长时间尺度上揭示秦岭南北地区主要河流洪水发生规律,深化特大洪水事件与季风气候的关系;同时也加深了对秦岭地理分界作用的认识,对秦岭南北因地制宜的进行防洪减灾和水资源的合理调度开发有重要的实践意义。展开更多
文摘在评价河流水文情势变化特征时,传统水文改变指标法(indicators of hydrologic alteration,IHA)存在的指标间相关性高和数据冗余问题会造成整体评价偏差。对汉江下游流域的河流水文情势评价时,考虑到汉江流域干支流日均流量及取水调水工程等的影响,分别选择汉江干流上的3个水文站及支流流域的3个水文站点,采用主成分分析法对6个水文站IHA指标进行优选,再利用相关性分析结果进一步筛选,优选出适用于评价汉江下游流域水文情势的13个代表性指标,分别为2月流量、4月流量、7月流量、10月流量、12月流量、基流指数、最低流量出现日期、最高流量出现日期、低流量脉冲次数、高流量持续时间、日均流量增加率、日平均流量减少率和日均流量反转数。结果表明:6个水文站的代表性指标间相关性均大幅降低,13个代表性指标间的相关系数不超过0.3的占比约70%;经变化范围评价法(range of variability approach,RVA)验证,IHA指标与优选出的代表性指标对汉江下游流域整体水文改变度评价结果的差值均小于7.5个百分点,表明其能够对汉江下游流域提供较为全面合理的水文情势变化评价。
基金Foundation: National Natural Science Foundation of China, No.41030637, No.41271108 Ph.D. Programs Foundation from Ministry of Education of China, No.20110202130002
文摘Palaeoflood hydrology study is a leading subject in global change study. Through field investigation in the upper reaches of Hanjiang River, palaeoflood slackwater deposits (SWD) were found in the bedrock gorges of the Yunxi reach. The results of field observation, laboratory analysis including particle-size distribution and magnetic susceptibility, and com- parison with modern flood deposits, the SWD were identified as the most typical Holocene palaeoflood deposits of the Hanjiang River. By using stratig;aphic correlation and OSL dating method, the palaeoflood event was dated to be 3200-2800 a BP at the turn from the middle to late Holocene. According to the palaeoflood peak stage and hydraulic parameters, the peak discharges of the palaeoflood were reconstructed as 48,830-51,710 m3/s by using the slope-area method. At same time, the flood peak discharges of 1983, 2005 and 2010 severe floods were reconstructed with the same method and hydraulic parameters in the same cross section. The error between the reconstructed and gauged discharges was 1.99%-4.21%. This showed that the reconstructed palaeoflood peak discharges were reliable. The flood peak discharge-frequency relationship at 10,000-year time scale was established by a com- bination of the gauged flood, historical flood and palaeoflood hydrological data. These results are very important for hydraulic engineering and flood mitigation on the Hanjiang River.
文摘以秦岭南北的汉江上游、渭河为例,对比分析了万年以来洪水发生的时间、流量的差异,并探讨了气候变化与洪水发生的联系。结果表明:在长时间尺度上,秦岭南北的汉江上游、渭河均有古洪水事件的沉积记录,汉江上游的洪水流量远大于渭河流域的洪水流量,洪水发生时间主要集中在4 200~4 000 a BP和3 200~3 000 a BP这两个时间段内;对季风气候变化分析表明,4 200~4 000 a BP和3 200~3 000 a BP是季风突变气候恶化的两个转折期,气候突变使得秦岭南北河流在这个时间段均有古洪水事件记录,但因测年分辨率的限制,似乎秦岭南北洪水发生时间具有一致性。在短时间尺度上,对秦岭南北实测洪水分析发现,虽然大多数年份秦岭南北没有洪水同时发生,但在个别年份内秦岭南北还是有洪水同时发生情况;从华西秋雨角度分析表明,秦岭南北的汉江上游、渭河处于华西秋雨核心区,但因多种因素的影响,在多数情况下秦岭南北洪水发生的时间并不都是完全相同。研究成果有助于从水文学角度在长时间尺度上揭示秦岭南北地区主要河流洪水发生规律,深化特大洪水事件与季风气候的关系;同时也加深了对秦岭地理分界作用的认识,对秦岭南北因地制宜的进行防洪减灾和水资源的合理调度开发有重要的实践意义。