杂交水稻对淹水胁迫的响应及排水指标研究

湖北平原地区夏季强降水频发,稻田易受洪涝灾害。为探明淹水胁迫对杂交中稻生长发育的影响,并在此基础上提出相应的排涝指标,在杂交中稻（丰两优香1号）分蘖期、孕穗期分别设计了淹水深度和淹水时间交互试验。结果表明：淹水处理后,水稻株高、第3、4节间均表现出伸长生长,且与淹水深度和持续时间的累积值（SD）呈显著线性正相关关系,但收获时遭受淹水的各处理其株高均矮于对照,且淹水程度越重,收获时株高越矮。淹水造成水稻减产,且淹水时间越长,淹水深度越深,减产越严重,若以产量受害指标为评价标准,孕穗期对淹水胁迫较分蘖期更敏感。就产量构成要素来看,分蘖期淹水胁迫导致水稻减产主要是有效穗下降、其次是结实率降低;孕穗期主要是结实率、千粒重下降,其次是有效穗减少。以相对产量（Ry）为参数建立的回归方程极显著地展示了Ry与SD、Ry与淹水深度和淹水时间之间的关系,可以作为水稻分蘖期、孕穗期的排涝方程。就淹水要素来说,分蘖期淹水深度对产量的影响比淹水时间大,而孕穗期淹水深度、淹水时间对产量的影响相当。若以水稻减产20%~30%作为排涝标准,分蘖期、孕穗期相应的SD值为1106~1944 cm/d（淹水深度≥18 cm）、265~805 cm/d（淹水深度≥25 cm）,并就具体的淹水深度提出了确切的排涝天数     

Socio-economic vulnerability of the megacity of Shanghai (China) to sea-level rise and associated storm surges

Sea-level rise (SLR) poses a significant threat to many coastal areas and will likely have important impacts on socio-economic development in those regions. Located on the eastern coast in China, the megacity of Shanghai is particularly vulnerable to SLR and associated storm surge risks. Using the municipality of Shanghai as a case study, the possible impacts of flooding risks caused by SLR and associated storm surges on socio-economic development in the region were analysed by a Source–Pathway–Receptor–Consequence (SPRC) conceptual model. The projections of flooding risk in the study area were simulated by MIKE21 (a two-dimensional hydrodynamic model) for the three time periods of 2030, 2050 and 2100. An index system for vulnerability assessment was devised, in which flooding depth, density of population, GDP per capita, GDP per unit land, loss rate under flooding and fiscal revenue were selected as the key indicators. A quantitative spatial assessment method based on a GIS platform was established by quantifying each indicator, calculating and then grading the vulnerability index. The results showed that in the 2030 projection, 99.3 % of the areas show no vulnerability to SLR and associated storm surges under the present infrastructure. By 2050, the areas with low, moderate and high vulnerabilities change significantly to 5.3, 8.0 and 23.9 %, respectively, while by 2100, the equivalent figures are 12.9, 6.3 and 30.7 %. The application of the SPRC model, the methodology and the results from this study could assist with the objective and quantitative assessment of the socio-economic vulnerability of other similar coastal regions undergoing the impacts of SLR and associated storm surges. Based on the results of this study, mitigation and adaptation measures should be considered, which include the controlling the rate of land subsidence, the reinforcement of coastal defence systems and the introduction of adaptation in long-term urban planning.     

Regional Risk Assessment addressing the impacts of climate change in the coastal area of the Gulf of Gabes (Tunisia)

Sound, cost efficient management strategies in developed coastal zones can be reinforced by a thorough understanding of risks associated with the combination of anthropogenic and natural drivers of change. A Regional Risk Assessment (RRA) methodology was developed for the assessment of the potential impacts of climate change in the Tunisian coastal zone of the Gulf of Gabes. It is based on the use of Multi-Criteria Decision Analysis techniques and Geographic Information Systems and is designed to support the development and prioritization of adaptation strategies. The RRA focuses on sea-level rise and storm surge flooding impacts for human and natural systems, i.e., beaches, wetlands, urban areas, agricultural areas, and terrestrial ecosystems. Results suggest that for both of the studied climate change impacts, i.e., sea-level rise and storm surge flooding, the area potentially exposed is limited to a narrow, low elevation region adjacent to the shoreline. However, the exposed areas showed a high relative risk score, obtained by the integration of exposure and susceptibility factors. Beaches have the lowest relative risk scores, while wetlands and terrestrial ecosystems have the higher relative risk scores. The final outputs of the analysis (i.e., exposure, susceptibility, and risk maps) can support end-users in the establishment of relative priorities for intervention and in the identification of suitable areas for human settlements, infrastructure, and economic activities, thus providing a basis for coastal zoning and land-use planning.     

西南地区公路洪灾孕灾环境分区

以西南地区公路洪灾为研究对象，在孕灾因子分析基础上构建由6个因子组成的孕灾环境分区指标体系，利用层次分析和专家效度相耦合方法确定各指标权重，采用综合指数法建立孕灾环境综合指数评价模型。在ArcGIS软件平台支持下获取各评价指标数据，并计算得到各网格孕灾环境综合指数值，以县级行政区为单位进行公路洪灾孕灾等级区的划分。研究表明：西南地区孕育公路洪灾发生的环境条件较充分，孕灾环境综合指数值在3313~7746，孕灾分区主要集中在中易发区和高易发区，其中高易发区占整个研究区面积的5718%，中易发区占4039%，低易发区占243%，公路管理部门在汛期防治洪灾的任务较繁重     

三峡库区消落带淹水—落干过程土壤磷吸附—解吸及释放研究

选取三峡库区消落带典型区土壤作为测试土壤，研究了淹水—落干对土壤磷的等温吸附解吸特性，以及土壤吸附一定的磷后再次淹水向上覆水体释磷的规律。研究表明：①三峡库区消落带土壤淹水—落干后吸磷能力增强，由淹水—落干前的256 mg/kg增加到淹水—落干后的625 mg/kg，磷零点吸持平衡浓度（EPC0）由淹水前的0.46 mg/L增加到淹水后的1.47 mg/L；②淹水—落干处理后土壤磷的解吸率降低，由淹水—落干前的73.3%~80.3%降低到67.3%~69.6%；③三峡库区消落带土壤吸附一定磷后，再淹水磷会再次逐渐释放到上覆水当中，且土壤吸附外源磷越多，磷淹水释放强度越大；④ 淹水—落干使吸附一定外源性磷的土壤淹水条件下释放更多的磷。     

Climate change,flooding in South Asia and implications

South Asia is one of the most flood vulnerable regions in the world. Floods occur often in the region triggered by heavy monsoon precipitation and can cause enormous damages to lives, property, crops and infrastructure. The frequency of extreme floods is on the rise in Bangladesh, India and Pakistan. Past extreme floods fall within the range of climate variability but frequency, magnitude and extent flooding may increase in South Asia in future due to climate change. Flood risk is sensitive to different levels of warming. For example, in Bangladesh, analysis shows that most of the expected changes in flood depth and extent would occur between 0 and 2°C warming. The three major rivers Ganges, Brahmaputra and Meghna/Barak will play similar roles in future flooding regimes as they are doing presently. Increases in future flooding can cause extensive damage to rice crops in the monsoon. This may have implications for food security especially of poor women and children. Floods can also impact public health in the flood plains and in the coastal areas.     

Community-based adaptation in low-lying islands in the Philippines: challenges and lessons learned

Community-based adaptation (CBA) seeks to address climate risks and socio-economic drivers of vulnerability simultaneously. However, as CBA activities appear very similar to standard development work, difficulties in identifying good practices arise. To clarify the role of CBA, this study elucidated how climate change can impact pre-existing development problems by investigating the experiences of four low-lying island communities in central Philippines. The islands currently suffer from frequent and extreme tidal flooding (following an earthquake-induced land subsidence in 2013, with a magnitude that is broadly similar to sea-level rise projections under a 1.5 to 2 °C global warming scenario), and endured a dry spell in 2016. The study also identified various publicly and privately initiated adaptation strategies, and evaluated their resilience against actual biophysical events. The study conducted focus group discussions with local leaders and in-depth interviews with government officials and residents in March 2016. Results show that tidal flooding impacted almost all aspects of daily life on the islands, while the dry spell completely depleted their limited water supplies. The strategies implemented by governments and NGOs (e.g., seawalls, rainwater collectors) were found to be inadequate in preventing tidal flooding and compensating for the dry spell. Also, communities used coral stones and plastic waste for raising the floors of their homes, which have an erosive effect on their capacity to adapt in the long term. Lack of community participation in publicly initiated projects and lack of adaptation funding for community-based strategies were the greatest obstacles to implementing climate-resilient solutions.     

我国水灾的基本特征及成因分析

本文研究了我国水灾的基本特征,分析了水灾形成的主要原因,提出了防御洪灾的措施。     

Responding to climate variability: the opening of an artificial mouth on the Senegal River

The city of Saint-Louis is marked by recurrent floods, despite the decrease in rainfall. The town that grew downstream the vast plain where Senegalese-Mauritanian basin topography flattens considerably has experienced periodic flooding since its foundation. In 2003, the premature flooding of the Senegal River urged the Senegalese authorities to take the initiative to open a breach in the coastal sand strip of the “Langue de Barbarie,” in order to evacuate the water surplus from the river to the ocean and therefore resolve forever the problem of river flooding. But the disruption of estuarine dynamics has led to a rapid expansion of this gap: a few meters wide at its excavation, it reaches over 2,700 m in August 2009. Moreover, 10 months after the widening of the gap, the old river mouth was completely closed. If the natural movement of a mouth can be observed on some major deltas in the world (even on the Senegal River in the past), this is here a true man-made relocation. Based on the statistical analysis of series of hydrological data, this article demonstrates on the one hand that climatic conditions in 2003 which generated a major flood is an anomaly detected in the sequence of dry climate variability observed in the Sahel. On the other hand, it studies the rapid evolution of this new mouth of the Senegal River and discusses some of impacts on the regional social–ecological system, in this sensitive Sahelian environment.     

基于AFI指数的汉江上游流域洪涝突变辨识

洪涝灾害往往容易在短期内突然发生，从而造成巨大的人员伤亡和财产损失，但目前有关突发性洪涝现象的甄别与分析并没有达成共识。在利用标准化前期降水指数SAPI(Standardized Antecedent Precipitation Index)评估出逐日洪涝状态的基础上，提出突变性洪涝指数AFI(Abrupt Flood Index)以综合反映水量由前期（当天）到后期（后10天）突变及后期洪涝程度，同时定义并计算AFI阈值AFI_t，认为AFI超过AFI_t的日期为临界状态，后期将发生突变性洪涝事件。以汉江上游流域为例计算出该流域1972~2017年逐日AFI指数，并利用AFI_t判别出了处于临界状态的日期。进一步分析表明，AFI指数能够较好地反映突变性洪涝现象，利用AFI指数甄别出的洪涝临界状态有利于识别流域突变性洪涝事件并有助于流域水资源系统应急管理。     

Laboratory experiments to predict changes in radiocaesium root uptake after flooding events

Changes in soil solution composition after a flooding event were hypothesised to be one of the key factors in explaining changes in radiocaesium incorporation in the food chain in the areas affected by the Chernobyl accident. A laboratory methodology was set up to monitor changes in the soil solution composition after a sequence of flooding cycles. Experiments were performed using column and batch approaches on test soils with contrasting initial soil solution composition (high and low initial concentrations of K+). Results from column experiments indicated a potential increase in NH(4)(+) concentrations, a parameter which could lead to an increase in the radiocaesium root uptake. Batch results in the soil with high initial K+ concentration showed that after a number of flooding cycles, especially for high ratios of flooding solution/mass of soil, K+ concentration decreased sometimes below a threshold value (around 0.5-1 mmol l(-1)), a fact that could lead to an increase in radiocaesium transfer. For the soils with a low initial K+ concentration, the flooding solution increased K+ and NH(4)(+) values in the soil solution. The comparison of test soils with soils from Ukraine areas affected by flooding showed that the final stage in soil solution composition was similar in both cases, regardless of the initial composition of the soil solution. Moreover, the comparison with unflooded soils from the same area showed that potential changes in other soil parameters, such as (137)Cs activity concentration, clay content, and radiocaesium interception potential, RIP (a parameter that estimates the radiocaesium specific sorption capacity of a soil), should also be monitored for additional effects due to the flooding event. Therefore, the changes in the root uptake would depend on the resulting situation from changes in RIP, K+ and NH(4)(+) values in the soil solution.     

洪泛区林地的开发对鱼类栖息地面积的影响模拟

洪泛区的开发利用,必然会导致洪泛区林地糙率的改变。河漫滩也是河流洪泛区的一部分。洪泛区糙率的减小,会使河水流速增大,从而减小鱼类可用栖息地面积。因此,在洪水发生时,为了给鱼类提供避险场所,保护有效栖息地面积,需研究洪泛区林地的开发对鱼类的影响。利用River 2D软件模拟在一定频率的洪水条件下,不同的河漫滩糙率对应的鱼类栖息地加权可用面积(WUA),分析了糙率的改变对河流鱼类栖息地的影响。结果表明:随着河漫滩糙率的降低,加权可用面积(WUA)逐渐减小,河漫滩范围内WUA的变化幅度比较大,河漫滩的特性对鱼类栖息地面积的影响很大。洪泛区植被的砍伐,会使鱼类栖息地面积减小。因此,应防止洪泛区的过度开发,保护河流生态环境。     

Mapping large areas of radioactively contaminated land with a self adapted, handheld, GPS coupled, scintillation detector

In Belgium, during several decennia, a phosphate plant discharged radium chloride containing waste water into two small rivers. One of those is part of a hydrographically very complex ecosystem with lots of small tributaries and hundreds of hectares of flooding zones. Hence, the river banks and large parts of these flooding zones have become contaminated with radium, heavy metals and chlorides. During a foot campaign, using a home made portable data logging system, consisting of a commercial 2.5 kg NaI detector, a computer mouse sized GPS, and a small pocket PC, the radioactive contamination of about 600 ha of sometimes very rough terrain was measured and mapped. The resulting very detailed radium contamination maps shed a whole new light on the water flow patterns of the ecosystem. The apparatus can also be used for efficiently guiding sampling campaigns for investigating other types of contamination. The ground maps are also compared to existing maps from helicopter measurements, evaluating strengths and weaknesses from both methods.     

Radium contamination of the banks of the river Laak as a consequence of the phosphate industry in Belgium

For over half a century, phosphate ores of marine origin, containing 226Ra, have been processed in Belgium to produce calcium phosphate for use in cattle food. As a result, the waste water containing 226Ra were discharged into two little rivers, one of which is the Laak. The purpose of this study was to chart the radium contamination of the river banks and some areas that are regularly flooded by the river. It was seen that enhanced concentrations of 226Ra do occur along the river banks, but that the contaminated area is mostly confined to a 10 m strip on both sides of the river, even in the flooding zones. At present, no dwellings are present on top of the contamination and no crops for direct human consumption are grown there, so there is no immediate threat to the population.     

Clusters of community exposure to coastal flooding hazards based on storm and sea level rise scenarios—implications for adaptation networks in the San Francisco Bay region

Regional Environmental Change - Sea level is projected to rise over the coming decades, further increasing the extent of flooding hazards in coastal communities. Efforts to address potential...     

Sea-level rise vulnerability in the countries of the Coral Triangle

Sea-level rise is a major threat facing the Coral Triangle countries in the twenty-first century. Assessments of vulnerability and adaptation that consider the interactions among natural and social systems are critical to identifying habitats and communities vulnerable to sea-level rise and for supporting the development of adaptation strategies. This paper presents such an assessment using the DIVA model and identifies vulnerable coastal regions and habitats in Coral Triangle countries at national and sub-national levels (administrative provinces). The following four main sea-level rise impacts are assessed in ecological, social and economic terms over the twenty-first century: (1) coastal wetland change, (2) increased coastal flooding, (3) increased coastal erosion, and (4) saltwater intrusion into estuaries and deltas. The results suggest that sea-level rise will significantly affect coastal regions and habitats in the Coral Triangle countries, but the impacts will differ across the region in terms of people flooded annually, coastal wetland change and loss, and damage and adaptation costs. Indonesia is projected to be most affected by coastal flooding, with nearly 5.9 million people expected to experience flooding annually in 2100 assuming no adaptation. However, if adaptation is considered, this number is significantly reduced. By the end of the century, coastal wetland loss is most significant for Indonesia in terms of total area lost, but the Solomon Islands are projected to experience the greatest relative loss of coastal wetlands. Damage costs associated with sea-level rise are highest in the Philippines (US $6.5 billion/year) and lowest in the Solomon Islands (US $70,000/year). Adaptation is estimated to reduce damage costs significantly, in particular for the Philippines, Indonesia, and Malaysia (between 68 and 99%). These results suggest that the impacts of sea-level rise are likely to be widespread in the region and adaptation measures must be broadly applied.     

Beyond ‘just’ flood risk management: the potential for—and limits to—alleviating flood disadvantage

Regional Environmental Change - The threat of flooding poses a considerable challenge for justice. Not only are more citizens becoming exposed to risk, but they are expected to play increasingly...     

Exposure of atoll population to coastal erosion and flooding: a South Tarawa assessment, Kiribati

Atoll countries are particularly vulnerable to coastal hazards in the context of global change, which justifies the interest in population exposure assessments. This paper contributes to addressing this need by assessing the current exposure of the population of two areas of the South Tarawa Urban District (Tarawa Atoll, Republic of Kiribati) to coastal erosion and flooding. The assessment is based on data relating to island morphology (digital terrain models and shoreline change), land use (building extension and coastal works) and environmental changes reconstructed for the 1969–2008 period. The results highlight rapid changes in land use and significant differences in current population exposure to coastal erosion and flooding between and within study sites. Between 1969 and 2007–2008, the built area located less than 20 m from the reference shoreline has increased by a factor of 4.2 at Bairiki and by a factor of 32.2 at Eita–Bangantebure, enhancing population exposure given that land elevation is low (12.6 and 77.4 % <2 m at Bairiki and Eita–Bangantebure, respectively). Nevertheless, in Bairiki, 87.5 % of the built area is currently not exposed to coastal erosion (>20 m from the coastline) and flooding (>1.5 m). Building exposure is higher at Eita–Bangantebure, where 71.3 % of the built area is currently not exposed (using the same criteria), but 17.1 % shows medium to very high levels of exposure, due to very low land elevation (22.3 % of the land area <1.5 m) and shoreline recession. The Eita–Bangantebure case study exemplifies the maladaptive trajectories of change that have been reported in other atoll countries.     

The undebated issue of justice: silent discourses in Dutch flood risk management

Regional Environmental Change - Flood risk of all types of flooding is projected to increase based on climate change projections and increases in damage potential. These challenges are likely to...     

上海市降雨变化与灾害性降雨特征分析

降雨是引发城市内涝的关键因素,与公众安全密切相关,分析其特征,能够为内涝防治提供一定参考和依据。上海地区气候条件复杂,深受暴雨、台风等水情灾害影响。依据国家基本气象站-宝山站数据,对上海市近40 a降雨变化和灾害性降雨特征进行了分析。结果表明上海年均降雨量以509 mm/10 a的速率递增。同时,降雨天数的减少较为显著,以3 d/10 a的速率递减。从降雨量和降雨强度的角度,灾害性降雨多为暴雨和短历时强降雨。上海年均暴雨天数为3 d,但雨量可占全年的1/5,大范围暴雨通常由台风引起。近年来,高于排水标准的短历时强降雨出现频次有增多的趋势。汛期作为灾害性降雨的高发期,可作为城市防涝的重点