灰关联分析方法在NAM模型参数敏感性分析中的应用

应用NAM模型对资水水系夫夷水流域新宁水文站的洪水过程进行模拟。利用灰色系统关联分析方法来研究NAM模型参数对模型模拟径流深、洪峰流量和峰现时间的影响。计算实例表明：浅层蓄水容量对NAM模型模拟径流深的影响较大,地表径流和壤中流汇流时间常数对NAM模型模拟径流深的影响较小;地表径流系数、地表径流和壤中流汇流时间常数对NAM模型模拟洪峰流量的影响较大,壤中流出流时间对NAM模型模拟洪峰流量的影响较小;地表径流和壤中流汇流时间常数对NAM模型模拟峰现时间的影响较大。     

NAM模型对参数变化敏感性的灰色关联分析

利用灰色系统关联分析方法分析了NAM模型参数变化对模拟径流深、洪峰流量和峰现时间的影响。结果表明:浅层蓄水容量对NAM模型模拟径流深的影响最小;地表径流系数、壤中流出流时间、地表径流和壤中流汇流时间常数对NAM模型模拟洪峰流量的影响较大,地表蓄水层蓄水容量和浅层蓄水容量对NAM模型模拟洪峰流量的影响较小;地表径流系数对NAM模型模拟峰现时间的影响最大,壤中流出流时间对NAM模型模拟峰现时间的影响最小。     

基于TOPMODEL的中小河流分布式洪水预报模型及其应用

近年来广东省中小河流洪水灾害频发,研究中小流域洪水预报模型对预防洪水灾害具有重要意义。本研究改进了传统的TOPMODEL模型,以栅格为单元构建了基于TOPMODEL的中小河流分布式洪水预报模型,并以高田水上游流域为研究对象,采用SCE-UA优选算法对1975—2008年的8场洪水进行参数优选,并对2010—2012年的4场洪水进行模型验证。模拟结果表明,本次预报在率定期和验证期平均确定性系数为0.85,径流深预报合格率为92%,峰现时间预报合格率为100%,模型模拟效果较为理想。用改进后的模型研究了某场洪水汇流过程不同时刻的空间分布情况,表明改进后的TOPMODEL模型能够直观地反映洪水的时空变化,模型具有一定的合理性和实用性。     

中田舍流域的产汇流模型研究

利用地理信息系统技术对中田舍流域数字高程模型(DEM)进行提取,获得地貌单位线中所需的地貌参数及其他流域信息,建立该流域的地貌单位线汇流模型,并利用实测资料验证其精度。结果表明:中田舍流域2016年3场洪水的模型模拟确定性系数均达到了0.9以上,模拟的洪峰与径流深的数值也较为相近,峰现时间的误差均在1 h之内。     

城西试验流域水文特性及水文过程模拟

水文试验是认识水文规律的重要基础工作。根据我国东部低山丘陵区城西试验流域的实测资料,分析不同尺度降雨径流之间的响应关系,再利用新安江流域水文模型进行径流模拟,进一步探讨该模型在我国东部低山丘陵区的适用性。结果表明:在试验流域空间尺度(几十平方公里)的暴雨洪水过程中,洪水峰现时间一般滞后雨峰3～4 h;场次和月尺度上的降雨径流具有较好的正相关关系;在日尺度上,降雨径流关系散乱,以10和70 mm降雨量为阈值呈U型分布; 3种时间尺度上,径流均受到前期退水过程的影响,其中,时间尺度越短,受前期退水过程的影响越显著;新安江流域水文模型在我国东部低山丘陵区具有较好的水文模拟能力,且月尺度水文过程的模拟效果优于日尺度,对天然流域的模拟效果优于人类活动扰动的流域。     

HEC-HMS模型在城市化流域洪水模拟中的应用

流域城市化过程影响了城市洪水形成的产汇流条件,显著增大了流域洪水模拟预报难度。采用HECHMS水文模型,选取秦淮河流域城市化前1980~1988年间共8场降雨-径流过程、城市化后2007~2013年间共7场降雨-径流过程开展洪水模拟研究,率定城市化前后不同土地利用情景下的产汇流参数,并设计城市化影响洪水模拟方案,对比分析城市化影响下的流域水文响应。结果表明:HEC-HMS模型在秦淮河流域城市化前后均具有很好适用性,且单峰洪水过程模拟精度高;城市化后流域内其他用地向城市建设用地转移,流域内不透水面积增加明显,使得产流量增加,洪峰流量增大,峰现时间提前约2 h。     

分布式单位线在河北雨洪模型中的应用

因河北雨洪模型的汇流计算方法难以用于无资料流域,其汇流参数难以获得且不宜移用,为此,将基于数字高程模型的分布式单位线用于河北雨洪模型,并对峪门口流域4场较大洪水过程进行了模拟。结果表明:4场洪水洪峰流量相对误差均<5%,峰现时间误差均<2 h,确定性系数均>0.85,模拟效果令人满意。河北雨洪模型与基于流域地形地貌特征的分布式单位线相结合,可解决无资料流域,特别是山丘地区中小流域的洪灾预警预报等问题。     

不同分布式水文模型在大洋河流域对比运用研究

为对比不同分布式水文模型在大洋河流域的径流模拟精度,基于大洋河沙里寨水文站2000—2010年水文数据,分别运用SWAT模型和VIC模型,模拟了大洋河沙里寨水文站以上流域2000—2010年径流。研究结果表明:SWAT模型比VIC模型更适合于大洋河流域的径流模拟,SWAT模型模拟的径流深相对误差均8%,确定性系数达到0.7以上,而VIC模型模拟径流深相对误差均10%,且确定性系数均0.6。     

基于SWMM的城市水文过程模拟及低影响开发策略研究

在全球气候变化和我国城市化进程加快背景下,城市水文环境受到极大的影响,如何对水文过程进行分析,并提出有效的治理措施成为当前的研究热点。结合某典型地区的基础资料,建立了基于暴雨洪水管理模型(storm water management model,SWMM)的城市水文过程模拟模型,通过分析不同频率的降雨情况,对城市排水能力、峰现时间等典型指标变化进行了研究,尤其针对城市排水问题提出了相对应的低影响开发(LID)策略,并给出了模型模拟研究结果。本文的研究结果能够为城市水文分析和城市化建设提供理论依据和技术支撑。     

基于河道洪水“平顶峰”过程的涨洪历时和流域汇流时间的判定

以依吉密河＂88.7.14＂特大洪水过程为例,探讨了暴雨洪水＂平顶峰＂过程的涨洪历时和流域汇流时间的判定问题,澄清了雨洪到峰时间和河道峰现时间的关系,为分析流域＂平顶峰＂类型洪水特性参数及洪水预报提供参考。     

红壤坡地降雨产流的数学模拟及其过程分析

基于运动波理论建立了自然降雨下红壤坡地产流模型,应用Preissmann隐式格式对模型进行数值求解,并通过实测资料对模型进行验证,结果表明计算值与实测值的相对误差最大不超过±17%,说明该模型是合理的,可以描述不同雨型下不同水土保持措施的红壤坡地产流规律。将试验实测的降雨过程输入到本文建立的模型中计算,得到不同雨型下的产流过程。分析表明:百喜草覆盖与敷盖措施的起始产流时间明显滞后于裸露地,而洪峰流量也明显小于裸露地,说明百喜草覆盖与敷盖措施都有明显的削峰滞流作用。     

Use of ensemble simulations to evaluate the urban effect on a localized heavy rainfall event in Tokyo,Japan

Recently, localized heavy rainfall over highly urbanized areas has caused severe damage in Japan. Although studies have indicated that the presence of urban areas can intensify rainfall, the chaotic noise caused by differences in initial conditions can change the urban effect. Therefore, the usability of ensemble simulation methods for urban effects on a single localized heavy rainfall event must be clarified to synthesize state-of-the-art observations and numerical model studies. This study examined the difference in a localized heavy rainfall event under different initial conditions. We demonstrated the advantage of ensemble experiments using a cloud-resolving model to evaluate the urban effect. In this study, we focused on a localized heavy rainfall event that occurred over Tokyo on 5 August 2008 and killed five people working in a drainpipe. Two ensemble experiments were performed according to the lagged average forecasting (LAF) method. Each experiment had six members, with initial conditions spanning 6 h from 02 to 07 Local Standard Time (LST) on 5 August 2008. The model was integrated continuously through 18 LST for each run. The model had a horizontal grid resolution of 2 km. The first experiment (CTRL) used the actual land cover, anthropogenic heat, and geometric structures. The second experiment (PDDY) used an imaginary land cover in which the urban area was changed to paddy fields. Comparison of the ensemble means showed that the peak value of the maximum hourly rainfall decreased and the peak time was delayed in PDDY compared with CTRL. The smaller peak value and delayed peak time of rainfall in PDDY seemed to be caused by the weaker updraft associated with near-surface convergence, which was caused by weaker surface heating. Regardless of the difference caused by the initial conditions, the decrease in the peak value and the delay in the peak time were significant according to the t-test. Although the area was limited compared with near-surface temperature and horizontal wind convergence, a significant reduction in rainfall was also seen over the heavily urbanized area of Tokyo in the horizontal distribution of the difference in accumulated rainfall. These results indicate that although differences in the initial condition can change the modeled urban effect on rainfall, ensemble simulation methods can be used to examine the significance of the urban effect on a single localized heavy rainfall event.     

Analysis of rainfall time series with regard to temporal disaggregation for the use in urban hydrology

The temporal resolution of rain data recorded by national weather services is often lower (10-min resolution) than the data needed for rainfall-runoff simulations (1–5 min resolution). However, the time series are sufficiently long for statistical analysis. The goal of the project presented here is to develop a procedure that disaggregates the 10-min rainfall data of the Swiss Meteorological Institute (SMI) to 1-min time resolution. The aim is to implement the procedure in a computer program which can be used by practitioners for generating high resolution rainfall time series at a specific location. In a first step the 1-min data and the 10-min data of two rainfall time series in Switzerland (Heiden, Lucerne) were compared to find characteristic patterns and correlations. The position of 1-min peak within the 10-min interval, the ratio of 1-min peak to 10-min intensity as well as the distribution of the 1-min values within the 10-min interval were investigated. The analysis showed that the positions of the 1-min peaks within a 10-min interval were not uniformly distributed. The distribution depended on the temporal trend of the 10-min values. The ratio of 1-min peak to 10-min intensity seemed to tend towards a constant ratio for high intensities. The results for the two series (Heiden and Lucerne) were not significantly different. These first findings are encouraging with regard to developing a disaggregation to 1-min values which satisfy the accuracy needed in urban hydrology.     

人工降雨条件下土工格室抗侵蚀性能试验研究

对长江以南低山丘陵区红壤土岸坡抗侵蚀性能开展定量研究具有重要意义。通过边坡模型实验,在人工降雨条件下对红壤土土工格室护岸进行了不同坡度、不同降雨强度及不同格室类型的降雨冲刷试验,对不同格室的抗侵蚀性能进行了定量分析。结果表明:在该试验降雨条件下,土工格室抗侵蚀性良好,对红壤土边坡的降雨冲刷防护效果明显,可在工程实践中推广应用。     

红壤坡地降雨产流的数学模拟及其过程分析

本文采用一维运动波理论建立了自然降雨下红壤坡地产流模型,应用Preissmann隐式格式对模型进行了数值求解,通过实测资料进行验证,计算值与实测值的相对误差最大不超过17%,说明该模型是合理的,可以描述不同雨型下不同水土保持措施的红壤坡地产流规律。将试验实测的降雨过程输入到本文建立的模型中计算,得到不同雨型下的产流过程。通过分析表明：百喜草覆盖与敷盖措施的起始产流时间明显滞后于裸露地,而洪峰流量也明显小于裸露地,说明百喜草覆盖与敷盖措施都有明显的削峰滞后作用。     

降雨空间尺度对径流模拟的影响研究

通过分析不同分辨率的雷达降雨数据所产生的降雨空间分布的变化对径流模拟的影响发现:本文所用的基于DEM的蓄满产流分布式水文模型对降雨时间和空间的变化是比较敏感的;由于降雨空间分辨率的变化计算的径流总量、洪峰都有不同程度的变化,但是这种变化的大小又与降雨场的特征、流域面积的大小以及土壤含水量的变化有很大的关系:随着面平均降雨量(P BAS)的增减,洪量也随着增减,P BAS与洪量有很好的相关性;降雨CV值的增加导致洪峰和洪量都相应的增加;流域的面积越小洪峰和洪量对降雨空间变化就越敏感;在前期干旱的条件下降雨空间变化导致的洪峰和洪量的变化要比在湿润的条件下产生的洪峰和洪量的变化大。     

城市流域径流峰值对降雨时空异质性的响应

基于高时空分辨率的降雨产品,采用RainyDay暴雨生成器生成具有不同时空分布情景和降雨历时的设计降雨,通过分布式水文模型GSSHA模拟分析径流峰值对降雨时空异质性的响应规律,结合协方差分析方法和所构建的降雨时空异质性指标体系,定量研究不同降雨时空异质性指标对径流峰值的影响。结果表明:耦合短时序(2008—2016年)栅格降雨数据和RainyDay暴雨发生器,可以生成与实际降雨时空分布相似的流域设计降雨;降雨时空异质性对径流峰值具有显著的影响,其影响比降雨历时和降水量对径流峰值的影响大;雨峰系数、降雨集中度、1 h最大降水量对径流峰值的影响较大,其中雨峰系数的影响随着降雨历时或降雨重现期增大而减小,而降雨集中度则相反。     

黄土区坡面侵蚀时空分布与上坡来水作用的实验研究

本文采用多坡段模型，运用模拟降雨实验方法研究了坡面侵蚀时空分布特征和上坡来水来沙的侵蚀作用，结果表明：坡面各部位的侵蚀方式与雨强密切对应。定量分析得出径流量、产沙量与坡度呈对数关系，与坡长呈线性关系，与雨强呈幂函数关系，建立了产沙量与坡度、雨强及径流量的关系式。同时也建立了产沙量、产沙增量与上坡来水来沙的关系方程，上坡来水使梁峁坡和谷坡产沙量增大了20.2%～63.5%和42.9%～74.5%。     

A Modified Hortonian Overland Flow Model Based on Laboratory Experiments

Overland flow, which is examined here, is an important hydrological response to storms of a catchment. And it is also a main component of hillslope hydrology. Through controlling of rainfall intensities and changing of artificial slope angles, 49 overland flow hydrographs are obtained from rainfall-runoff simulation experiments conducted on a manmade hillside. Based on the measured overland flow processes, the relationship between the average water depth on the hillslope and that at the outlet, which is nearly a quadratic curve, is obtained. The relationship is different from the assumption, in which the average water depth on the hillslope is equal to that at the outlet, proposed by Horton. Finally, a regression equation is also presented, which provides both the theoretical and experimental basis to modify the time delay of peak flow for a distributed rainfall-runoff modeling.