降雨条件下边坡水文响应及其变形过程分析——以深圳大龙山边坡为例

以深圳大龙山边坡为例,采用水分计、张力计、渗压计、固定式测斜仪和雨量计等针对边坡开展了降雨量、不同部位边坡土体基质吸力、体积含水量、孔隙水压力和深部水平变形等的监测,对降雨条件下边坡水文过程和内部变形进行了分析,发现当日降雨量较小时,如在2009年4月18日日降雨量为52.4mm/d的情况下,地表以下0.5m和1m深度土体含水量和基质吸力都发生响应;日降雨量较大时,如在2009年5月23日、24日连续两天日降雨量超过100mm/d的降雨情况下,3m深度内的体积含水量和基质吸力均表现响应;渗压计P4的地下水位距离地表只有约6m的距离,监测到瞬态孔隙水压力对降雨响应及其敏感,其余渗压计的孔隙水压力基本未发生变化,推测持时短的暴雨易造成山体边坡的浅层滑坡。同时,该边坡在3m内的累积位移相对较大,最大累积如测斜IN3A向累积位移接近10mm。但累积位移无继续增大的趋势,处于稳定状态。     

降水临近预报及其在水文预报中的应用研究进展

随着全球气候变化、自然变迁及陆表生境改变,极端天气频发且呈现出多尺度时空变异特征,对其进行预报和预警一直是气象水文领域关注的焦点。临近预报可较准确地预报未来短时间天气显著变化,是当前预报强降水等极端事件的主要手段。从基于天气雷达0～3 h外推临近预报、融合数值模式0～6 h临近预报的发展历程梳理了临近预报的研究进展,阐述了雷达外推算法的发展进程、雷达外推预报与数值模式预报融合技术进展,指出"取长补短"的0～6 h融合预报在提高降水预报精度、延长降水预见期等多方面有较大的发展潜力,进一步探寻及提升融合技术是未来融合预报发展的核心。将临近预报以气象水文耦合的方式引入水文预报是从源头提高水文预报精度、保障水文预报效果的主要途径,总结了现阶段主流耦合方式、空间尺度匹配技术、水文模型不确定等陆气耦合中的关键问题,阐述了外推临近预报、融合临近预报作为水文预报输入的研究进展,明确了融合临近预报在延长洪水预见期、提高洪水预报精度中存在优势,并讨论了未来的研究重点及发展方向。     

不同时间尺度的中长期水文预报研究

为研究中长期水文预报时间尺度对预报精度的影响,选取最近邻抽样回归模型与基于小波分析的组合模型对长江干流典型断面不同时间尺度的径流序列进行中长期径流预报。将1980~2012年的逐日径流资料经过时间聚集方法转换成三天、周、旬、半月、月、双月、季、半年、九月、年等10个不同时间尺度,对高场、寸滩、宜昌、螺山、汉口、大通6个典型断面的径流进行拟合和预报。结果表明:随着预报时间尺度增加,预报精度呈现先降低后提高的趋势,其中,在月时间尺度上预报效果最差,三天和年尺度上预报效果相对较好。     

全国水文预报技术竞赛参赛流域水文模型分析

对全国首次水文预报技术竞赛中参赛的10个流域水文模型的结构及模拟技术,分别从各个主要环节进行分类与综述;并根据技术竞赛检验结果所揭示的现象,就参赛水文模型的模拟及应用进行了分析与讨论。     

Assimilation of Doppler weather radar observations in a mesoscale model for the prediction of rainfall associated with mesoscale convective systems

Obtaining an accurate initial state is recognized as one of the biggest challenges in accurate model prediction of convective events. This work is the first attempt in utilizing the India Meteorological Department (IMD) Doppler radar data in a numerical model for the prediction of mesoscale convective complexes around Chennai and Kolkata. Three strong convective events both over Chennai and Kolkata have been considered for the present study. The simulation experiments have been carried out using fifth-generation Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) mesoscale model (MM5) version 3.5.6. The variational data assimilation approach is one of the most promising tools available for directly assimilating the mesoscale observations in order to improve the initial state. The horizontal wind derived from the DWR has been used alongwith other conventional and non-conventional data in the assimilation system. The preliminary results from the three dimensional variational (3DVAR) experiments are encouraging. The simulated rainfall has also been compared with that derived from the Tropical Rainfall Measuring Mission (TRMM) satellite. The encouraging result from this study can be the basis for further investigation of the direct assimilation of radar reflectivity data in 3DVAR system. The present study indicates that Doppler radar data assimilation improves the initial field and enhances the Quantitative Precipitation Forecasting (QPF) skill.     

分布式降雨径流物理模型的建立和应用

根据流域降雨径流的主要过程,考虑流域气象及下垫面要素的空间异质性,建立了具有物理基础的分布式降雨径流模型。模型将流域离散为栅格计算单元,并按水流特性分栅格单元为坡面单元和河网单元。在坡面单元上主要计算降雨、下渗、坡面流、壤中流等水文过程,而河网单元则主要计算河道汇流过程。模型利用空间权重插值方法将雨量站点的降雨量插值到各个计算单元,采用运动波方程来计算坡面流,将壤中流概化为垂向流和侧向流,分别用Green-Ampt公式和运动波方程来模拟,河道汇流也采用运动波方程。模型结构简单、参数的物理意义明确,大多数参数可利用DEM、土壤类型图、植被类型图直接获取,少数敏感参数通过率定确定。模型在浙江省甬江上游黄土岭流域和皎口流域进行了应用和检验,其结果令人满意。     

大通河流域土地利用/覆被变化的水文响应

以大通河流域为研究区域,利用1985年和2005年土地利用数据,结合SWAT分布式水文模型定量评估了流域土地利用/覆被变化的水文效应。结果表明：1985-2005年大通河流域的土地利用变化主要表现为草地向耕地、居工地转变,草地所占比例由46.7%骤降至20.9%,而耕地面积由1985年的1065.8km²增加到2005年的3243km²;相较于1985年的土地利用情景,2005年土地利用情景下的模拟的多年平均径流增加了1.92×10⁸m³,由于上中下游主要的土地利用/覆被变化不同,导致流域径流变化增加程度由西北至东南逐渐增大;大通河流域年径流的增加主要表现为汛期径流增加,讯期月平均径流增幅达到了0.40×10⁸m³·mon^-1;非汛期径流则呈不明显减小趋势,平均降幅为0.024×10⁸m³·mon^-1。合理规划大通河流域土地利用方式,提高水源区涵养能力,对流域水资源可持续发展具有重要意义。     

基于分布式水文模型的雅鲁藏布江径流水源组成解析

为开展河川径流的水源解析,构建过程描述和本构参数两方面均有较强物理性的分布式水文模型。以雅鲁藏布江为对象,利用水文分区曲线对降雨、融雪和融冰等不同水源主导的流量过程进行划分,以划分的流量过程线子集对相应水文过程参数进行分步率定,提高了水文模型参数的物理性,以此构建了雅鲁藏布江流域分布式水文模型及参数集,内部多个水文站点和流域雪水当量的验证表明模型具有良好的性能。基于模型解析了2001-2015年间雅鲁藏布江的径流水源组成,降雨、融雪、融冰水源对总径流量贡献的比例分别为66%、20%和14%。本文方法对高山寒区径流的水源解析有普遍意义,结果对理解气候变化下雅鲁藏布江径流变化趋势有参考价值。     

基于分布式水文模型的雅鲁藏布江径流水源组成解析

为开展河川径流的水源解析，构建过程描述和本构参数两方面均有较强物理性的分布式水文模型。以雅鲁藏布江为对象，利用水文分区曲线对降雨、融雪和融冰等不同水源主导的流量过程进行划分，以划分的流量过程线子集对相应水文过程参数进行分步率定，提高了水文模型参数的物理性，以此构建了雅鲁藏布江流域分布式水文模型及参数集，内部多个水文站点和流域雪水当量的验证表明模型具有良好的性能。基于模型解析了2001—2015年间雅鲁藏布江的径流水源组成，降雨、融雪、融冰水源对总径流量贡献的比例分别为66%、20%和14%。本文方法对高山寒区径流的水源解析有普遍意义，结果对理解气候变化下雅鲁藏布江径流变化趋势有参考价值。     

1957—2019年昆仑山北麓车尔臣河流域水文情势及其对气候变化的响应

气候变暖背景下干旱区水文、水资源的变化仍是影响区域水资源利用和洪水灾害防治的关键科学问题。基于1957—2019年长序列的水文、气象资料,系统分析了昆仑山北麓车尔臣河流域的水文变化特征及其对气候变化的响应。总体上,车尔臣河流域的水文过程的显著变化发生在1990s末期,变化前后年径流量约增加了54.67%,所有季节径流的增加共同造成了年径流的增加,其中夏季径流的增加对年径流增加的贡献最大,其次依次为秋季、春季和冬季。降水增加（第一控制因素）和气温升高（第二控制因素）共同造成了车尔臣河流域水文过程的变化。具体到径流年内变化,降水是春夏季径流变化的主控因素,而秋冬季径流变化的主控因素是气温。径流增加为中下游提供更多水资源的同时,也导致年际间水文洪涝和干旱事件发生的频率增加、强度增强。冰冻圈在该地区水文循环中起着重要的作用,但其对水文过程的影响仍不明确,加强阿尔金高山区的冰川、多年冻土监测将为进一步预估水文对气候变化的响应提供基础数据支撑。     

典型岩溶包气带洞穴滴水水文过程研究——以桂林硝盐洞为例

选取桂林丫吉试验场硝盐洞为研究对象,通过示踪试验和高分辨率水文水化学监测,确定滴水补给来源,研究典型岩溶包气带洞穴滴水对降雨响应的水文过程。研究结果表明,硝盐洞XY5滴水主要受到两种径流成分补给,即集中补给的管道流和弥散流。硝盐洞上部包气带中可能存在表层岩溶带含水层,长期维持滴水流量。滴水流量、电导率和示踪剂浓度的峰值均出现在强降雨时段,表现出快速响应的管道流特征,存在降雨阈值引起硝盐洞滴水降雨响应。降雨前岩溶含水层水分条件是包气带水文响应差异的主要原因,雨季滴水对降雨响应迅速,XY5滴水对降雨响应的滞后时间为10 h;而旱季对降雨的响应滞后明显,滞后时间达9.8天,体现了土壤和表层岩溶带的调蓄作用。74.4 mm降雨量是旱季转雨季滴水响应的降雨阈值。借助于洞穴滴水的水文动态变化和示踪试验技术对于研究包气带水文过程,深入了解岩溶含水层结构及特征,揭示岩溶区降雨入渗补给机制具有重要作用。     

分布式水文模型中河流水深及其与地下水相互作用的耦合模拟

大尺度流域水文模型一般只模拟河道径流,对河流水深和流速并不关注。在进行河流-地下水相互作用模拟时,河流水深（水位）是一个重要因素,其时空变化及其对河流-地下水水量交换的影响应加以考虑。本文就流域分布式水文模型中河流水深的时空变化计算及其与地下水的实时耦合模拟进行了研究,提出了相应的计算方法,改进了大尺度水文模型WATLAC,并通过V-型流域考题进行了检验。模拟结果显示,模型有效地模拟了V-型流域的河流水深、地下水水位沿河道的时空变化以及河流与地下水的水交换量,揭示了河流-地下水相互作用关系在降雨过程中的变化规律及主控因子。此外就河床糙率对河流水深及河流与地下水间水交换量的影响做了模拟分析,发现河床糙率的改变将影响河流水深,从而进一步影响河流与地下水的水交换量。本文提出的算法较为真实地模拟了河流洪水演进过程及其对河流-地下水相互作用的影响,模型适用于河流-地下水相互作用明显的区域,可作为评估地表-地下水相互影响的有效计算工具。     

延安治沟造地小流域水库氨氮对降雨变化的响应

地球关键带是以小流域为单元的近地表开放系统。流域内坝库体系作为小流域物质迁移的重要汇集区,将坝库水体作为研究对象,监测其物质浓度变化,并与气候变化和人类活动等因素进行关联性分析,对于理解和预测小流域物质迁移过程、规律和变化趋势具有基础理论意义和现实指导意义。当前,流域水文过程与氮迁移的耦合研究较多关注硝态氮,而对氨氮关注较少,导致了关键带过程中水文和氮循环耦合过程的部分环节缺失。本研究以延安顾屯治沟（填沟）造地小流域为对象,研究小流域水库氨氮浓度周时间尺度的动态变化及其与降雨的联系,揭示强烈人类活动影响下黄土小流域氨氮迁移特征和可能的内在机制。通过对上游至下游5座水库氨氮浓度连续1年（2016年6月至2017年5月）的每周监测,结果表明：5座水库氨氮浓度变化均滞后于降雨事件1~2周,而与月降雨量和降雨前流域湿润指数的变化趋势相比,则滞后1个月;不同季节之间,5座水库夏季和秋季氨氮浓度远高于冬季和春季。水库与地下水的氨氮浓度变化趋势一致,且存在显著线性关系（p < 0.001）,表明降雨可能通过影响地下水氨氮浓度从而影响水库氨氮浓度。降雨入渗的影响因素,如降雨量、降雨强度、降雨持续时间和降雨前流域湿润程度,控制着水库氨氮浓度上升的幅度。从空间分布来看,小流域上游至下游水库氨氮浓度呈显著正相关（p < 0.001）,且相邻2座水库氨氮相关系数大于不相邻水库。降雨量较大的夏季、秋季和春季水库间氨氮浓度变化的相关性均大于降雨量较小的冬季。这些现象表明,降雨是延安治沟造地小流域水库氨氮的重要控制因素,其中水分在雨水-地下水-水库系统和上游水库-下游水库系统的迁移过程起到关键性作用。

     

盾构施工引起地层变位的实时决策系统设计

介绍了盾构施工引起地层变位实时决策系统的总体结构,分析了各个模块的功能。以灰色模型为例,建立了盾构施工引起地层变位的安全监控模型。归纳了对地层变位异常值检查的评判准则,并进行异常值的成因分析,提出了安全度的概念作为综合评价方法。工程实例表明,该系统具有数据存储和查询功能,将监测数据、监控模型、系统评判可视化,实现了对地层变位的综合评判,有助于盾构施工的信息化管理和反馈。     

Hydrological response of a dryland ephemeral river to southern African climatic variability during the last millennium

A long-term flood record from the Buffels River, the largest ephemeral river of NW South Africa (9250 km²), was reconstructed based on interpretation of palaeoflood, documentary and instrumental rainfall data. Palaeoflood data were obtained at three study reaches, with preserved sedimentary evidence indicating at least 25 large floods during the last 700 yr. Geochronological control for the palaeoflood record was provided by radiocarbon and optically stimulated luminescence (OSL) dating. Annual resolution was obtained since the 19th century using the overlapping documentary and instrumental records. Large floods coincided in the past within three main hydroclimatic settings: (1) periods of regular large flood occurrence (1 large flood/~30 yr) under wetter and cooler prevailing climatic conditions (AD 1600–1800), (2) decreasing occurrence of large floods (1 large flood/~100 yr) during warmer conditions (e.g., AD 1425–1600 and after 1925), and (3) periods of high frequency of large floods (~ 4–5 large floods in 20–30 yr) coinciding with wetter conditions of decadal duration, namely at AD 1390–1425, 1800–1825 and 1915–1925. These decadal-scale periods of the highest flood frequency seem to correspond in time with changes in atmospheric circulation patterns, as inferred when comparing their onset and distribution with temperature proxies in southern Africa.     

SHIA_Landslide: a distributed conceptual and physically based model to forecast the temporal and spatial occurrence of shallow landslides triggered by rainfall in tropical and mountainous basins

Landslides are a main cause of human and economic losses worldwide. For this reason, landslide hazard assessment and the capacity to predict this phenomenon have been topics of great interest within the scientific community for the implementation of early warning systems. Although several models have been proposed to forecast shallow landslides triggered by rainfall, few models have incorporated geotechnical factors into a complete hydrological model of a basin that can simulate the storage and movement of rainwater through the soil profile. These basin and full hydrological models have adopted a physically based approach. This paper develops a conceptual and physically based model called open and distributed hydrological simulation and landslides—SHIA_Landslide (Simulación HIdrológica Abierta, or SHIA, in Spanish)—that is supported by geotechnical and hydrological features occurring on a basin-wide scale in tropical and mountainous terrains. SHIA_Landslide is an original and significant contribution that offers a new perspective with which to analyse shallow landslide processes by incorporating a comprehensive distributed hydrological tank model that includes water storage in the soil coupled with a classical analysis of infinite slope stability under saturated conditions. SHIA_Landslide can be distinguished by the following: (i) its capacity to capture surface topography and effects concerning the subsurface flow; (ii) its use of digital terrain model (DTM) to establish the relationships among cells, geomorphological parameters, slope angle, direction, etc.; (iii) its continuous simulation of rainfall data over long periods and event simulations of specific storms; (iv) its consideration of the effects of horizontal and vertical flow; and (vi) its inclusion of a hydrologically complete water process that allows for hydrological calibration. SHIA_Landslide can be combined with real-time rainfall data and implemented in early warning systems.     

滑坡对降雨响应的多指标监测及综合预警探析:以赣南罗坳滑坡为例

降雨量和位移是当前降雨型滑坡监测预警最常用的指标。然而,降雨量和位移监测结果只能反映降雨作用下滑坡的变形情况,不能揭示滑坡内在物理力学性状对降雨的响应。因此,除降雨量和位移监测之外,建立包括体积含水率、基质吸力等反映滑坡动态演化过程的关键指标监测体系必将成为今后更真实地把握滑坡内在演化趋势、更准确地建立滑坡综合预警判据的最有效手段。笔者对赣南地区典型降雨型滑坡进行了多指标监测及综合预警示范研究。结果表明:(1)在降雨条件下滑坡土体内部体积含水率、基质吸力和温度等多指标均产生有规律的动态响应;(2)随着降雨的持续,滑体体积含水率与基质吸力的变化均具有显著的滞后现象;(3)体积含水率和基质吸力变化速率与滑体位移具有显著的正相关性;(4)滑体温度分布变化规律受大气温度和体积含水率的共同影响。以实测数据的滑坡稳定性分析为基准,在考虑实际降雨入渗深度与滑坡稳定性的关联度上,建立了包括日降雨量、体积含水率增加速率、基质吸力减小速率以及位移速度多元指标预警方法体系,提出了基于关键指标综合预警体系及确定方法,旨在为降雨滑坡准确预警提供新模式。     

Monitoring Flood Extent and Forecasting Excess Runoff Risk with RADARSAT-1 Data

Earth observation from active microwave satellites such as RADARSAT-1 is an excellent tool to monitor and forecast floods. Two complementary approaches are described in this paper: (a) real time or near-real time monitoring of flood extent and (b) mapping of hydrological properties of drainage basins. Since it can penetrate through clouds, which usually occur during precipitation periods, and due to the fact that it can be programmed with different incidence angles, RADARSAT-1 enables frequent coverage over specific areas of interest. It has been used successfully to monitor a major flood of the Red River in Manitoba in 1997, by providing frequent coverage of the flood during its progression and decrease. Resulting data and images have been useful in planning the emergency measures and in assessing flood damage. RADARSAT has also the ability to characterize hydrological properties of watersheds. It has been used in agricultural catchments in Europe for mapping soil surface roughness, which affects runoff coefficients, concentration time and resistance to erosion processes. Used to complement optical data, RADARSAT has provided information on the status of land use and soil protective cover in drainage basins. This information can then be translated into parameters and coefficients that hydrological models can use for runoff and flood forecasting     

Fingerprinting the 8.2 ka event climate response in a coupled climate model

Using results from coupled climate model simulations of the 8.2 ka climate event that produced a cold period over Greenland in agreement with the reconstructed cooling from ice cores, we investigate the typical pattern of climate anomalies (fingerprint) to provide a framework for the interpretation of global proxy data for the 8.2 ka climate event. For this purpose we developed an analysis method that isolates the forced temperature response and provides information on spatial variations in magnitude, timing and duration that characterise the detectable climate event in proxy archives. Our analysis shows that delays in the temperature response to the freshwater forcing are present, mostly in the order of decades (30 a over central Greenland). The North Atlantic Ocean initially cools in response to the freshwater perturbation, followed in certain parts by a warm response. This delay, occurring more than 200 a after the freshwater pulse, hints at an overshoot in the recovery from the freshwater perturbation. The South Atlantic and the Southern Ocean show a warm response reflecting the bipolar seesaw effect. The duration of the simulated event varies for different areas, and the highest probability of recording the event in proxy archives is in the North Atlantic Ocean area north of 40° N. Our results may facilitate the interpretation of proxy archives recording the 8.2 ka event, as they show that timing and duration cannot be assumed to correspond with the timing and duration of the event as recorded in Greenland ice cores. Copyright © 2011 John Wiley & Sons, Ltd.     

岩溶隧道涌水对降雨的响应特征

引入时间序列分析方法,以铜锣山岩溶长大隧道为例,采用相关分析和频谱分析,定量研究了该隧道涌水对降雨的响应特征。结果表明,隧址区岩溶地下水系统储量十分丰富,具有很强的调节能力和过滤作用,致使隧道涌水与降雨的相关程度不高,平均滞后时间长达12.62 d,由此推断,隧道涌水与降雨之间的连通性较差。此研究成果可为隧道后期的防排水管理提供科学依据。