全球气候变化与水文水资源问题关系到人类的生存与发展，涉及国家政治与安全、社会经济发展、人类协调与合作等一系列问题。气候变化改变了水文循环过程，影响着水资源系统的结构与功能，对人类水资源的开发利用带来新的挑战，并深刻影响着人类社会水资源的开发、利用、规划、管理等诸多环节。探讨气候变化影响下的水资源及其相关科学问题成为全球共同关注和各国政府的重要议题之一。水循环及其变化特征与机理是水文水资源理论研究中最具根本性的科学问题，也是亟待解决的难题。从社会需求来看，其研究具有重大的实践意义；从结合应用的角度，全球水循环与全球变化的水资源和水文响应，特别是气候变化下水循环问题是其中最为重要的基础科学问题。近几年来，由于全球气候变化导致水循环发生显著变异，进一步导致极端水文气象事件（如暴雨、旱涝灾害、风灾等）频发，对人类社会、生态等产生重大影响，因而区域乃至全球尺度的水循环及其水资源与水文响应研究备受关注。气候变化必然引起水循环的变化，从而影响河川径流，进而导致流域地表水文过程的变异。除此之外，河川径流变化还受人类活动等方面的影响。人类活动使流域下垫面发生变化，如土地利用、水库大坝的兴建、水土保持生态工程的修建、城市化等都会改变水文循环，从而影响到河川径流。虽然人类活动的范围是局部的，但是影响强度在某些地区却是很显著的。定量界定气候变化和人类活动对河川径流的影响以及地表水文过程的变异对流域水生态与水环境的影响，不仅是气候变化影响研究领域中的科学问题，同时也是目前流域管理者所关心的重大科学问题。水文学发展的历史表明，社会需求是水文学发展最基本的动力，它决定了水文学发展的方向和进程。进入20世纪90年代以来，社会发展对水文学的需求主要表现在，为防灾减灾、水资源可持续利用、生态环境保护和社会与经济可持续发展等方面提供水文学依据。作者正是针对上述科学问题，以长江流域与珠江流域为主要研究区域，在气象水文学领域开展系统而深入的研究，逐步形成较为完整的理论体系。

目前，随着全球性水问题的出现和对水资源问题认识的深入，对水文气象现象及其机理的深入研究已被世界各国普遍承认是未来水资源管理的重要科学支撑，也是当前国际水文学学术前沿领域的重大科学问题，基于此，作者经过10余年的系统研究，揭示全球气候变化背景下中国南方大河流域区域水循环演变特征及其机理，研究水循环变化对区域降水与流域地表水文过程的影响方式及程度；探讨人类活动（如大型水利工程建设等）对流域水文过程（包括径流与输沙过程）的影响；变化环境下区域水文系统变异及其对流域生态影响的定量化研究，并在诸多研究成果基础上，形成该专著的主体内容。该专著总结了作者自2003年以来的研究成果，以流域水循环与水资源演变为主线，初步形成较为完整的科学认识体系。

本书共分九章：

第1章 系统阐述流域水循环与流域地表水文过程研究的进展、学科前沿等问题。

第2章 气候系统的输出—降水对水循环的影响是最为直接的。对某一特定的区域而言，一定程度上可以说降水是水循环的开始。作者通过对全国范围内乃至长江流域与珠江流域降水的系统分析，研究发现了中国6个降水一致性区域，在不同区域发生不同的降水特征。该章还总结了作者另外一项研究，发现中国南方大河流域，如珠江流域，降水强度与波动性增强明显，而低强度降水日数减少；降水总量变化甚微，但是降水波动变化增加显著，从而使旱涝灾害发生几率增大。

第3章 论述了蒸散发研究的意义及主要科学问题。总结了作者在蒸发方面研究的主要工作，即干旱区与湿润蒸散发过程对比研究以及中国蒸散发时空变化特征及影响因子。

第4章 讨论了当前全球气候变化研究所关注的重要科学问题之一，即气象与水文极值（如旱涝灾害、台风灾害、暴雨及风灾等）频发，对人类社会、经济发展以及社会稳定等造成重大影响。这既是当前的一个重大科学问题，也是国家保障经济社会可持续发展与社会稳定的重大科技需求。同时，总结了作者在这个领域做的主要工作，即对气象与水文极值时空演变规律与归因的研究以及物理机理解析。作者以长江流域（包括长江三角洲）与珠江流域（包括珠江三角洲）为研究区，将定性研究与定量分析相结合，全面辨析长江流域上、中、下游气象水文极值的变化规律与成因，包括长江流域水沙变化规律及成因研究。另外，基于Copula函数对珠江流域连续最大（最小）7d流量进行多变量联合概率分布分析，深入探讨了最大流量与最小流量的相遇概率及珠江流域下游旱涝灾害发生概率，基于研究成果，对珠江流域下游水资源管理与水资源合理配置等重要应用问题提出建议。

第5章 历史气候记载有着记录时间准确、气候变化信息详细等诸多优点，而且在长期的研究中，人们已总结出利用历史气候记录研究气候变化的有效方法，历史气候记录已成为延长器测资料，从较长时段审视气候变化不可多得的珍贵数据，因而利用历史气候记录研究旱涝灾害也已引起国际学术界的高度重视。作者利用长江三角洲地区丰富的历史资料，与南京地理与湖泊研究所陈家其研究员合作，重建长江三角洲地区旱涝灾害序列，进行了一系列的分析与研究工作，得出了有意义的结果。该章总结了以历史文献记载为基础的主要研究工作，一个是研究了青藏高原气候变化对长江三角洲地区旱涝灾害影响研究；另一个是研究了长江三角洲地区旱涝灾害序列的可预测性与分形特征。该研究进一步从理论上论证了利用历史文献当中的旱涝灾害信息研究并预测未来旱涝灾害发生规律的可行性。

第6章 总结了作者在地表径流尺度演变特征研究方面的主要工作，研究了长江流域水文序列是非平稳序列，揭示了长江流域上、中、下游水文序列不同的自相关性特征。作者以东江流域为例，从多重分形特征的角度研究了水库对下游地表水文过程影响的动力学特征。另外一个重要工作是水文分形分析中一个理论问题，即如何消除水文序列的周期性对水文序列分形特征的影响研究。

第7章 总结了作者在水文变异研究中的工作，以长江流域与珠江流域为主要研究区，系统研究了中国南方大河流域水文要素变异特征、程度与成因。

第8章 珠江三角洲地区地势低平，河网密布，珠江三角洲地区水位变化受上游地表水文过程、下游的海平面以及咸潮等变化的影响，水位变化复杂。同时，由于珠江三角洲地区水位变化受多种因素的综合影响，因而水位变化成因分析的复杂程度高。但是，该水位变化直接关系到该区域水资源管理与利用问题，如水位上升则有增加淹没损失的风险，而水位降低则有增加咸潮入侵，从而导致城市取用水困难的风险。因而，珠江三角洲地区水位变异及成因分析，有着重要的理论与科学意义，更具有重要的实际价值。作者根据研究区水位变化研究的特殊性及研究需求，创造性的改进了RVA与IHA方法，分析了珠江三角洲地区水位变异强度的时空演变特征。同时利用贝叶斯模型与Lepage突变分析方法分析珠江三角洲地区水位的变异特征。

第9章 水文模型是研究地表水文过程以及气候变化与人类活动对地表水文过程影响的一个强有力的工具。该章总结了作者目前为止做的主要工作。

本书是作者近十年来对华南大河流域，尤其是关于长江流域与珠江流域水循环与水资源演变方面研究成果的总结。本书共分九章，系统总结了珠江流域与长江流域乃至整个中国区域的极端气象水文过程变化、珠江流域与黄河流域蒸发变化对比研究、珠江流域水文极值多变量概率分析、长江流域水沙变化及成因探讨、珠三角水位变化及成因分析以及历史洪旱序列模拟与长期记忆性研究等多项研究成果。本书涉及气象水文学、气象水文极值分析与多变量概率分析方法及应用、多尺度水沙突变分析、分形理论与方法等多学科的理论与方法的应用研究，一方面揭示了中国南方典型流域水文循环时空演变特征及机理，同时为多种统计方法及分形理论在气象水文现象研究中的应用提供典型研究案例，并为相关研究提供分析思路及参考。

本书可供水文水资源、水生态、水环境、水利工程、地理、资源及有关专业科技工作者和管理人员使用，也可供大专院校相关专业师生参考阅读。

Global climate changes and hydrological and water resources issues have considerable implications for human society and development，and also concerns social security，socio-economic development and international collaboration.Climate changes alter the hydrological cycle processes，influencing structure and functions of water resources system，posing new challenges for human exploitation of water resources and meaning too much for development，usage，planning and management of water resources.In this sense，hydrological cycle and related changing properties and possible mechanisms are the core issues in the hydrology and water resources and are also the scientific problems needing urgent attentions.In recent decades，the hydrological cycle was considerably altered by global changing climate，and hence the frequent occurrences of weather and hydrological extremes such as rain storms，floods and droughts and wind hazards etc.，which have profound impacts on human society，inflicting tremendous losses on socio-economy.Hydrological alterations are one of the consequences of climate changes and which is the key factor resulting in alterations of fluvial hydrological alterations.Besides，fluvial hydrological variations are also heavily impacted by human activities.Human activities caused changes of underlying surfaces，such as land use and land cover changes，construction of water reservoirs，conservation of soil and land and urbanization，and all these factors tend to contribute to the alterations of fluvial hydrological processes.The influences of human activities on hydrological processes are sometimes local or regional，however the degree of intensity of human influences are usually significant and can not be ignored.In this sense，quantitative evaluation of impacts of climate changes and human activities on fluvial streamflow and ground-surface streamflow variations and related influences on eco-hydrological requirements are the relevant scientific issues and also the key issues the policy-makers concern much.Historical development of hydrology science tells the story that the social requirements are the fundamental impetus and the major driving factor for the improvement of the hydrology as a subject.Entering the 1990s，mitigations of natural hazards，sustainable usage of water resources，and conservation of ecological environment and sustainable development of the socio-economy continue to pose increasing and enhancing challenges for the development of hydrology.The research group focuses on the foregoing scientific problems and contributes great efforts to the study of hydrological phenomena by taking the Yangtze River and the Pearl River as case studies.

In recent years，increasing hydrological problems such as shortage of water resources in a wide sense and also the improving knowledge of water resources emphasize the study of meteor-hydrological phenomena and related mechanisms.With this mind，the major objectives of this series of studies are：（1）to investigate the changing properties and related underlying causes of the hydrological cycle at a regional scale in the rivers of the south China，analyzing the way and the degree of the impacts of the hydrological cycle alterations on the regional precipitation processes and ground-surface hydrological processes；to probe into the impacts of human activities such as construction of hydraulic facilities on the fluvial streamflow processes including the sediment load and streamflow changes；to evaluate in a quantitative way the impacts of the alterations of regional water system on the fluvial ecological environment.This study is the integrated study involving interdisciplinary methods or techniques in terms of different spatial and temporal scales.The current report summarizes the research results of the research group since 2005 and the theoretical system is coming into being after the considerable efforts of study and analysis.The report is based on more than 60 publications in Chinese and English.Generally，the report involves nine chapters and the contents of the chapters will be introduced briefly in the following：

Chapter 1 This chapter introduces the key scientific issues in terms of hydrological cycle，ground-surface streamflow variations and also related frontier scientific problems；

Chapter 2 Precipitation is the key component of the hydrological cycle.Precipitation is sometimes regarded as the starting point of the hydrological cycle.The research group analyzed the precipitation changes in the Yangtze River，the Pearl River and also the entire China，showing six regions with homogeneous precipitation changes.Besides，different precipitation patterns have been identified for different regions.Besides，the study also obtained another important finding that hydrological alterations are reflected mainly by the altered precipitation structure such as decreasing rainfall days and increasing rainfall events.The precipitation total is in moderate changes but is characterized by larger-magnitude of changing variability which undoubtedly increases the probability of flood and drought hazards；

Chapter 3 This chapter discusses the significance and the major scientific problems in terms of evapotranspiration.Our work in this field mainly focuses on the comparisons between the evapotranspiration changes in the arid and humid regions.The evaporation changes over China，changing properties and influences factors are also investigated；

Chapter 4 This chapter summarizes the research results by the research group with respect to the weather and hydrological extremes.The research group studied and analyzed the changing characteristics and attributions.By taking the Yangtze River basin and the Pearl River basin as case studies，the research group analyzed the changes of hydrological extremes including sediment load and streamflow changes.Besides，hydrological extremes defined by consecutive 7 day high flow and consecutive 7 day low flow components are also analyzed by using the copula functions，probing into the joint probability behaviors of these two hydrological extremes；

Chapter 5 Historical documented records of floods and droughts are invaluable for the investigation of changes of natural hazards from the viewpoint of long time interval.The research group reconstructed and analyzed the changes of floods and droughts in a last 1000 years，exploring the impacts of the Tibet Plateau on the occurrences of floods and droughts in the Yangtze Delta region.In addition，the predictability and fractal properties of the flood and drought series are also anatomized by using IFS and RIFS models.These studies further clarified the feasibility of study on historical floods and droughts based on the historical documented records；

Chapter 6 This chapter summarized the study in terms of scaling properties of streamflow series.The major findings are the invariant scaling properties of streamflow series and different correlation structures of streamflow series in the upper，the middle and the lower Yangtze River basin.Besides，the impacts of the water reservoirs on the downstream hydrological processes are analyzed by using multifractal detrended fluctuation analysis；

Chapter 7 This chapter summarizes the work about the hydrological alterations，such as the features，degree and causes of hydrological alterations of the hydrological processes in the rivers of the south China，specifically the Yangtze River and the Pearl River；

Chapter 8 Due to rapid urbanization and industrialization，the PRD region has witnessed environmental changes within only one to two decades and comparable changes in developed countries may have occurred only after up to one century of development.Human activities such as engineering constructions and other modifications of the Pearl River network in such a changing environment might cause hydrologic alterations in terms of river flows，stages，and flow partition at river bifurcations，channel cross-sections and hydraulic gradients.Changes in these hydrologic regimes may have crucial implications for almost all aspects of water resources management in the region，including flood protection，land use，water supply，channel navigation，and water pollution control.Abnormally high or low water level has the potential to give rise to the salinity intrusion，flood inundation and water logging，negatively influencing the economic development and human activities in the PRD.This chapter summarized the major findings by the research group in the Pearl River Delta region.

Chapter 9 Hydrological model is the power tool in the simulations of the hydrological changes.This chapter summarizes the major findings in this field.