洪水灾害在全球范围内造成了巨大的影响和人口、财产损失。在全球变暖影响下，全球及区域洪水灾害系统也处在动态的变化过程中，且呈加剧趋势，给人类社会生命财产安全带来了极大威胁。洪水灾害对人类社会造成了广泛的影响，这已引起了社会各界的密切关注。然而，洪水灾害系统的形成和演变过程复杂，影响因素多元且内部相互作用，已有研究对于洪水灾害的形成机制，以及社会经济和地理环境等对于洪水灾害系统的影响分析尚存缺陷，从而影响到洪水灾害应急管理工作的有效性。而从全球至区域等不同空间尺度审视洪水时空特征及影响因素，对于全面理解洪水过程空间效应及洪水过程对气候变化与人类活动的区域响应差异性与影响因子，以及洪水灾害的时空尺度效应方面的理论研究和防洪减灾的应用方面，具有重要科学与理论意义。因而，开展全球及区域等不同空间尺度洪水灾害时空演变格局、变化规律及其影响因素，对于探究并科学地认识和推动洪水灾害管理实践有重要理论与实践意义。一方面，有利于加深气候系统和人类社会系统对极端水文过程影响的认识，实现气候与人类系统和极端灾害研究的综合性交叉研究；另一方面，有利于系统全面地认识洪水灾害时空变化规律和影响因素，为洪水灾害的动态管理提供科学依据与理论支撑。 基于以上考虑，本研究以洪水灾害系统理论为研究理论基础，围绕全球及区域洪水灾害系统动态演变过程这一主题，在全球、洲际和国家等不同空间尺度上，从洪水灾害时空格局、动态演变和关键影响因素等三方面，对洪水灾害的形成及演变规律进行了全面的研究，并探究了不同影响因素对洪水灾害空间分布格局的影响程度，该研究主要结果及结论如下： 1. 全球范围内因洪伤亡人口增加，主要原因是全球范围内洪水频次显著增加。基于EM-DAT和DFO等多源历史洪灾数据，全面分析了全球1975-2016年间重大洪水频次、强度、死亡人口和受灾人口等时空格局，结合降水、热带气旋和社会经济发展数据分析结果，系统并深入探讨了洪灾的影响因素。通过上述分析所得研究结果发现：（1）全球范围内洪水频次及因洪死亡人数、因洪受灾人数总体呈增加趋势，但单次因洪死亡和受灾人数呈下降趋势，表明因洪水频次增加导致的因洪伤亡人口的增加已超过单次因洪伤亡人口减少的数量；（2）各洲洪灾频次均呈不同程度增加，而单次因洪死亡人数年际变化受极端洪水事件的影响显著。具体来讲，亚洲洪灾频次、因洪人口死亡率为最大，其中，中国、印度、印尼、菲律宾等国洪灾频次、受灾人数和死亡人数较大。中国、美国、澳大利亚等国的洪水受灾人数、年均人口损失等均呈显著上升趋势。 2. 东亚及东南亚是全球受洪灾影响最大的区域，其中受洪灾影响最大的国家为中国、印度及孟加拉，东亚、东南亚沿海区域洪灾的主要影响因子是热带气旋。基于全球的洪水灾情分析，发现亚洲国家的洪水灾害对全球灾情具有主要贡献作用，故对该区域洪水灾害时空特征及影响因素进行了深入研究，通过深入分析发现：（1）亚洲地区洪水灾情最为严重的国家是中国、印度和孟加拉。东亚、南亚和东南亚的洪水灾害从人口死亡数量方面来看最为严重，但是西亚和中亚的因洪死亡率较高。通过分析研究发现，从洪灾影响因素来看，热带气旋导致的洪水灾害事件区域与台风发生最密集的区域基本吻合，而且洪水频次更高、洪水灾情更加严重的地区台风强度越大；（2）洪水灾害严重程度较高的洪水事件多发于印度东部、中国东南部、东南亚、东亚等地区。印度半岛东部的因洪死亡人数最多，其次是太平洋西岸；（3）热带气旋时空变化与亚洲因洪人口损失有显著相关性，这些区域河道型洪水发生频次为全球最高，而死亡人口占各类型洪水死亡总数较大的快速洪水，人口死亡率也为最高。因而亚洲沿海国家应对热带气旋导致的洪灾及热带气旋变化给予足够重视；（4）亚洲人口密度及单位面积GDP与单位面积受灾人数、死亡人数和经济损失呈显著正相关。因洪人口受灾率和死亡率与人均GDP呈负相关关系，但人均经济损失与人均GDP呈正相关，以上结果说明人口和GDP密度越大的地区，洪灾脆弱性也相应增加。因此，在亚洲季风区应加强对洪水灾害的设防能力，在西亚等干旱和半干旱地区应重视极端天气带来的巨灾影响，对突发性暴雨导致的洪水灾害的应急管理工作应更加重视。 3. 中国暴雨洪涝灾害频次呈增加趋势，气象因素是因洪受灾人口变化的主导因子，而地理及社会经济因素是因洪死亡人口变化的主要影响因子。中国是世界上人口最多的国家，而主要的人口分布区及经济发达地区多集中于中国东部沿海及中国东南沿海，灾害脆弱性高、灾害暴露度大，因而是研究洪灾及其影响的典型区。而目前对于中国的洪涝灾情研究多停留在省市级尺度，缺乏对中国各区域洪水灾害空间格局的影响因素的深入分析。通过对中国县级气象灾情普查数据分析，结合小时降水数据、统计年鉴等灾情统计资料等，系统分析了1984到2007年间中国的极端降水和暴雨洪涝灾情的时空格局，采用地理探测器对暴雨洪涝灾情时空格局的影响因素做了定量分析。结果表明：除了少部分地区外，全国雨量站的极端降雨指标没有一致的趋势，但近年来中国各个地理区划的暴雨洪涝灾害频次呈增加趋势，洪灾频次在长江流域、珠江流域及东南沿海等区域的显著增加和因洪死亡率的下降，表明了上述区域洪灾设防能力的提升；因灾死亡人数和受灾率、经济损失等在新疆等西北地区均增加；不同类型的影响因素在不同时期对暴雨洪涝灾情的贡献率不同，其中对因洪受灾人口贡献率最高的因子是气象因素，对因洪死亡人口贡献率最高的是地理和社会经济因素，而因洪直接经济损失贡献率最高的是地理因素。 该研究从不同时空尺度和多学科交叉的视角，系统分析了全球、亚洲和中国县级区域等不同空间尺度洪水灾情时空演变规律和影响因素，并进一步剖析了不同区域的关键影响因子。国内外许多研究结果表明，全球洪水灾害频次和强度最高的地区主要位于亚洲的发展中国家，随着以气候变暖的影响逐渐增强，这些地区的洪水风险将会在未来进一步增加，应提高这些地区的洪水灾害适应能力和洪水灾害风险防范工作，对区域综合防洪减灾能力进行提升。除了气候系统影响因素外，高程、坡度、河网密度、城市化率、GDP密度等都对洪水灾情的空间分布具有重要影响，且这些影响因素随着人类社会的发展而发生着动态变化。对于亚洲新兴经济体国家而言，在进行城市规划的同时，构建有效的洪水灾害管理体系尤为重要。

Flood disaster has caused enormous impact and massive loss of population and property worldwide. Under the influence of global warming, Global and regional flood disaster systems are also undergoing dynamic changes and are intensifying, posing a significant threat to the safety of human life and property worldwide. The widespread and far-reaching impact of flood disasters on human society has drawn considerable attention from the international academic community. However, the occurrence and evolution processes of the flood disaster system is complex, and the influencing factors are diverse and inter-correlated. The existing researches have a flaw on the occurrence mechanism of flood disasters and the impact of socio-economic and geographical environment on flood disaster systems, thus inflicting the effectiveness of flood risk management. In this context, investigating the spatial-temporal characteristics and influencing factors of flood from global to regional spatial scales has important scientific and theoretical significance for fully understand the spatial effect of flood disaster process and its regional differences of response to climate change and human activities and influencing factors, as well as the theoretical research of the scale effect of flood disaster and application of flood control and mitigation. Therefore, it is of great theoretical and practical significance to explore, scientifically understand and promote the practice of flood disaster management to carry out the spatial and temporal evolution pattern, change rules and influencing factors of flood disaster at different spatial scales. On the one hand, it is conducive to enhance the knowledge of the influence of climate and human society system on extreme hydrological processes, and achieving the combination of climate change and extreme disaster risk research. On the other hand, it is of great significance to systematically understanding the changing patterns and influencing factors of flood disasters, and providing a scientific reference and theoretic backup for dynamic management of flood disasters. Based on the above considerations, this thesis studied the formation and evolution of flood disasters and the impact of different factors on flood disasters by considering the flood disaster system theory as the basic theory and focuses on the spatiotemporal pattern, dynamic evolution of flood disasters and influencing factors on the global, intercontinental and national scales centered on the theme of global and regional dynamic evolution mechanism of flood disaster system. The aforementioned analyses and results can help to achieve the following findings: 1. I found increased flood frequency over the globe and the higher frequency of flood regimes is the major cause behind increased flood-induced mortality and hence the increased flooding risks. Based on multi-source historical flood data such as EM-DAT and DFO, the spatiotemporal patterns of major flood frequency, intensity, death population and affected population on the global scale from 1975 to 2016 were comprehensively analyzed. The cause was discussed combining with precipitation, tropical cyclone and socio-economic development data. Research indicates: （1） occurrence rate of floods, flood-induced mortality and flood-affected population were generally increasing over the globe. However, flood-induced mortality and flood-affected people per flood event were in slight decrease, indicating that flood-induced mortality and flood-affected people as a result of increased occurrences of floods exceeded those by individual flood event; （2） increasing occurrences of floods can be observed over continents across the globe, while the annual variation of mortality due to one individual flood event is highly related to floods with higher intensity. Specifically, the largest flood frequency and flood-induced mortality are the largest in Asia. Wherein, larger flood frequency, flood-induced mortality and number of deaths can be observed in China, India, Indonesia and Philippine; while significant increase can be detected in flood-affected population and mean annual mortality in China, USA and Australia. 2. I found that East Asia and Southeast Asia are heavily influenced by flood disasters and China, India and Bangladesh in particular. Tropical cyclone changes play the key role in driving flooding regimes in these regions such as East Asia and Southeast Asia. Based on the analysis of flood disasters on global scale, it is illustrated that flood disasters in Asia have a major contribution to global disasters. Therefore, an in-depth study of this region has been conducted. It is found that: (1) the countries that dominate the flood disasters in Asia are China, India and Bangladesh, and floods in Asia are the most serious in East Asia, South Asia and Southeast Asia, but the mortality rate in West Asia and Central Asia is extremely high. From the perspective of influencing factors, the flood disaster area caused by the tropical cyclone is basically consistent with the area with the highest intensity of typhoon, and the typhoon intensity is higher in the area with higher flood frequency and more serious flood disaster; (3) The spatiotemporal variations of tropical cyclone （TC） are closely related to flood-induced mortality in the countries along the western coast of the oceans in Asia. The frequency of channel floods in these regions is the largest and large proportion of flood-induced deaths and the highest flood-induced mortality can be attributed to TC-induced flash floods. Therefore, mortality due to TC-induced flash floods should arouse considerable human concerns from the countries along the western coast in Asia; （4） Population density and GDP per unit area are in significantly positive correlation with the number of flood-related victims per unit area, number of deaths and economic losses with exception of low-income countries. However, the flood-affected population and flood-induced mortality increase with decrease of per capita GDP; while the per capita economic loss increases with the increase of per capita GDP, indicating that the higher the population density and GDP per unit for a region, the higher sensitivity of this area to flood hazards. Therefore, in the Asian monsoon region, the ability to prevent from flood disasters should be strengthened. In arid and semi-arid regions such as West Asia, attention should be paid to the impact of the extreme weather. The emergency management of sudden heavy rain and flood disasters also need improvement in this regions. 3. I found increased rainstorm-induced flood disasters in China. Meteorological factors have considerable contributions to flood-affected population and geographical and socioeconomic factors have massive contributions to flood-induced mortalities. China is the most populous country in the world, the major population distribution areas and economically developed areas are mostly concentrated in the east coast and southeast coast of China, with high disaster vulnerability and high disaster exposure. Therefore, China is a typical region for studying flood disasters and their impacts. At present, the research on flood disasters in China mostly stays at the provincial and municipal scales, and the lack of analysis of the causes behind flood disasters has limited the progress of flood risk management. Here we investigated changes of flood disasters in both space and time and their driving factors behind using statistical data of the meteorological disasters from Statistical Yearbooks and also hourly rainfall data covering a period of 1984-2007. Geo-detector method was used to analyze potential driving factors behind flood disasters. We found no consistent extreme rainfall trend across China with exceptions of some sporadic areas. However, recent years witnessed increased frequency of rainstorm-induced floods within China and significant increase in the frequency of flood disasters in the Yangtze River, Pearl River and Southeastern coasts. Meanwhile, reduced flood-related death rates in the regions with increased flood frequency indicated enhanced flood-mitigation infrastructure and facilities. However, increased flood-induced affected rates and direct economic losses per capita were found in the northwestern China. In addition, fractional contributions of influencing factors to flood disasters are shifting from one region to another. While we found that rainfall changes play the overwhelming role in driving occurrences of flood disasters, other factors also have considerable impacts on flood disasters and flood disaster-induced losses such as topographical features and spatial patterns of socio-economy. Wherein, topography acts as the key factor behind flood disasters. This research conducted an in-depth analysis of the spatiotemporal evolution and influencing factors of flood disasters in the world, Asia and China from different scales and perspectives, and deepens the understanding of flood disaster systems. As can be seen from the full text, developing countries in Asia currently have the highest contribution rate to global flood disasters. As climate change is intensifying, flood risk in these areas will increase further in the future, and climate change adaptation in these areas should be improved. Flood risk government will strengthen the capacity of regional comprehensive disaster prevention and mitigation. In addition to climate change factors, elevation, slope, river network density, urbanization rate, and GDP density all have great impact on the spatial distribution of flood disasters, and these influencing factors change dynamically with the development of human society. For Asian emerging economies, it is especially important to build an effective flood risk management system while conducting urban planning.