Simulation and Analysis of Sea Floods in the Don River Delta

Storm surges and wind waves in the Taganrog Bay (the Sea of Azov) are simulated with the ADCIRC+SWAN numerical model, and the mechanisms of the Don River delta flooding are analyzed. It is demonstrated that the most intensive flooding of the Don River delta occurs in case of southwestern wind with the speed of not less than 15 m/s. A storm surge leads to the intensification of wind waves in the whole Taganrog Bay due to the general sea level rise. As a result, the significant wave height near the Don River delta increases by 0.5–0.6 m.     

The impact of changing environments on the runoff regimes of the arid Heihe River basin, China

This study analyzed the inter- and inner-annual variations of discharge regimes in the upper and mid reaches of the Heihe River basin. These variations then correlated with temperature and precipitation variations in the area. The differences between the runoff regimes at the upper and mid reaches were compared, and the human impacts on discharge variations in the Heihe River were discussed. The results indicate that in the upper reaches, the long-term trends and periods of discharge and precipitation correlate well. In the mid reaches, the discharge and temperature trends correlate well, and the short discharge and precipitation periods correlate well. Precipitation increases would generate more runoff in both the upper and mid reaches, but the effects of temperature increases on discharge are different in the upper and mid reaches. Temperature increases would enhance the glacial ablation processes and increase runoff in the upper reaches. However, temperature increases would increase the evaporation and decrease runoff in the mid reaches. After the 1980s, higher temperature enhanced snow and glacial melt, and increasing precipitation increased the discharge in the upper reaches. Although increasing precipitation increased some discharge, great human activities caused a notable discharge decrease in the 1990s in the mid reaches, especially during the spring to autumn when large amounts of water resources were used for irrigation. In summary, both precipitation and temperature impact the availability of water resources in the study area, and active and effective adaptation strategies should be developed to improve the efficiency of water resource exploration and to prevent the desertification processes in the arid Heihe River basin.     

Adaptive environmental governance of changing social-ecological systems: Empirical insights from the Okavango Delta,Botswana

Adaptive management and related fields have theorized new governance strategies that embrace complexity and are able to respond effectively to changing and unpredictable biophysical dynamics. However, this body of work pays inadequate attention to important on-the-ground realities, including feasibility of implementation and the power dynamics embedded in multi-scalar systems of environmental governance. This paper presents findings from a research project on challenges to adaptive management in the variable wetland ecosystem of the Okavango Delta, Botswana. Many residents of this rural region rely on transitional agricultural practices, shifting between dryland and floodplain farming in response to dynamic precipitation and flooding patterns. Higher than average floods in 2009–2011 inundated many floodplain fields past the point of production, causing farmers to shift to the dryland for multiplem seasons. At the same time, the highly centralized Government of Botswana began to implement stricter regulations over floodplain resources, which stemmed in part from a new adaptive management plan developed for the region. As a result, many farmers felt pressured by the government to abandon transitional livelihood practices and to shift permanently to dryland agriculture even though many preferred to continue floodplain farming. This loss of a responsive livelihood strategy will likely result in decreased long-term adaptive capacity for many residents. Drawing on these findings, this paper advances the argument that if adaptive management is to become a viable option for communities in changing environments, more attention must be given to the role of unequal power relations in multi-scalar systems of environmental governance.     

Modeling the impact of urbanization on the local and regional climate in Yangtze River Delta, China

The Yangtze River Delta Economic Belt is one of the most active and developed areas in China and has experienced quick urbanization with fast economic development. The weather research and forecasting model (WRF), with a single-layer urban canopy parameterization scheme, is used to simulate the influence of urbanization on climate at local and regional scales in this area. The months January and July, over a 5-year period (2003–2007), were selected to represent the winter and summer climate. Two simulation scenarios were designed to investigate the impacts of urbanization: (1) no urban areas and (2) urban land cover determined by MODIS satellite observations in 2005. Simulated near-surface temperature, wind speed and specific humidity agree well with the corresponding measurements. By comparing the simulations of the two scenarios, differences in near-surface temperature, wind speed and precipitation were quantified. The conversion of rural land (mostly irrigation cropland) to urban land cover results in significant changes to near-surface temperature, humidity, wind speed and precipitation. The mean near-surface temperature in urbanized areas increases on average by 0.45?±?0.43°C in winter and 1.9?±?0.55°C in summer; the diurnal temperature range in urbanized areas decreases on average by 0.13?±?0.73°C in winter and 0.55?±?0.84°C in summer. Precipitation increases about 15% over urban or leeward areas in summer and changes slightly in winter. The urbanization impact in summer is stronger and covers a larger area than that in winter due to the regional east-Asian monsoon climate characterized by warm, wet summers and cool, dry winters.     

Climate change and water resources in the Bagmati River Basin,Nepal

This paper characterizes potential hydrological impact of future climate in the Bagmati River Basin, Nepal. For this research, basinwide future hydrology is simulated by using downscaled temperature and precipitation outputs from the Hadley Centre Coupled Model, version 3 (HadCM3), and the Hydrologic Engineering Center's Hydrologic Modeling System (HEC-HMS). It is predicted that temperature may rise maximally during the summer rather than winter for both A2 and B2 Special Report on Emissions Scenarios (SRES) scenarios. Precipitation may increase during the wet season, but it may decrease during other seasons for A2 scenario. For B2 scenario, precipitation may increase during all the seasons. Under the A2 scenario, premonsoon water availability may decrease more in the upper than the middle basin. During monsoons, both upper and middle basins show increased water availability. During the postmonsoon season, water availability may decrease in the upper part, while the middle part shows a mixed trend. Under the B2 scenario, water availability is expected to increase in the entire basin. The analysis of the projected hydrologic impact of climate change is expected to support informed decision-making for sustainable water management.     

The impact of water resources development projects on water vapor pressure trends in a semi-arid region, Turkey

The aim of this study was to investigate long-term seasonal trends and decadal change patterns of monthly mean water vapor pressure (WVP) observation series at 16 meteorological stations scattered point-wisely over the Southeastern Anatolian Project (GAP) area in Turkey, where large-scale soil and water development projects have been put into practice since the 1970s. The record length of WVP observation series of each station varied between 31- and 41-years between 1962 and 2002. The monthly mean WVP observation series of each station was rearranged on seasonal basis. Sequential Mann–Kendall trend test, Sen’s slope estimator, and Spearman’s rank–order correlation tests were employed for detection of likely trends, and Kruskall–Wallis test was used to detect decadal variations in WVP series of each observation station. A possible area of representation for each meteorological station was determined by using the Thiessen polygons technique in a geographical information systems media. It was found that 15 seasonal WVP series have a positive trend covering 97% of the GAP area in the summer season; although one WVP series has a negative trend direction. However, in the spring season, 33% of the area had a positive trend, and a negative trend did not appear in any stations. WVP records in the winter season showed an increasing trend over 19% of the GAP area, whereas a decreasing trend prevailed in 9% of the area. The study results led us to conclude that the substantial increase of WVP observations in summer season could be attributed to both the shift from rain-fed agriculture to irrigated agriculture being made increasingly spacious year by year and building large water reservoirs in the GAP located in a semi-arid region. The results also indirectly suggested that the historical trends in the WVP parameters might be related to global climate change phenomenon.     

The evolution of climate change impact studies on hydrology and water resources in California

Potential global climate change impacts on hydrology pose a threat to water resources systems throughout the world. The California water system is especially vulnerable to global warming due to its dependence on mountain snow accumulation and the snowmelt process. Since 1983, more than 60 studies have investigated climate change impacts on hydrology and water resources in California. These studies can be categorized in three major fields: (1) Studies of historical trends of streamflow and snowpack in order to determine if there is any evidence of climate change in the geophysical record; (2) Studies of potential future predicted effects of climate change on streamflow and; (3) Studies that use those predicted changes in natural runoff to determine their economic, ecologic, or institutional impacts. In this paper we review these studies with an emphasis on methodological procedures. We provide for each category of studies a summary of significant conclusions and potential areas for future work.     

Accessing adaptation: Multiple stressors on livelihoods in the Bolivian highlands under a changing climate

Smallholder farmers continuously confront multiple social and environmental stressors that necessitate changes in livelihood strategies to prevent damages and take advantage of new opportunities, or adaptation. Vulnerability, meaning susceptibility to harm, is attributable to social determinants that limit access to assets, leading to greater exposure and sensitivity to stressors and a limited capacity to adapt. Stressors and adaptation are intertwined because stressors deplete resources available for adaptation, while adaptation may erode resources available to respond to future stressors. We present empirical evidence demonstrating the interactions of multiple stressors and adaptations over time through a case study of indigenous farmers in highland Bolivia. We examine how farmers perceive the stress on their livelihoods, their strategies for adapting to these threats, and the influence of past adaptation and exposure on vulnerability under increasing climatic change. We find that vulnerability changes over time as multiple stressors, such as land scarcity and delayed seasonal rainfall, compound, simultaneously reducing access and demanding the expenditure of household assets for adaptation, including natural capital (water and land), human capital (including labor), and financial, physical, and social capital. To reduce vulnerability over time, constraints on access to key resources must be addressed, allowing households the flexibility to reduce their exposure and improve their adaptive capacity to the multiple stressors they confront.     

气候变化、植被改变及人类用水与黄河流域水循环的研究进展

受气候增暖和人类活动的双重影响,黄河流域的水循环正在发生显著变化,水资源供需矛盾突出。陆地水循环是一个复杂的非线性系统,为清晰认识水循环变化的全貌,并合理高效利用有限的水资源量,需要综合考虑水循环各个要素之间的协同变化机制。同时,在“人类世”背景下,黄河流域水循环研究必须考虑人类活动的影响,主要包括植被变化和人类用水,其中人类用水主体为农业灌溉。自从实施生态恢复工程以来,黄土高原植被覆盖明显改善的同时也引发了对径流、蒸散发、降水、土壤湿度以及地下水的一系列影响,且研究结论还存在一些争议,但黄土高原植被覆盖改善使得该地区蒸散发量增加基本达成共识,大多数研究支持植被改善减少径流的结论。黄河流域的农业灌溉方式主要为大水漫灌,其对地表蒸散发、地表水及地下水多个过程具有重要影响。本文主要针对黄河流域的水循环研究,讨论相关研究进展以及发展方向。     

The landscape technology of spate irrigation amid development changes: Assembling the links to resources, livelihoods, and agrobiodiversity-food in the Bolivian Andes

Spate irrigation is increasingly recognized as contributing to potential of accessible water-resource use, local food production, and resource sustainability. This study constructs an approach to spate irrigation as a landscape technology by selectively fusing concepts of resilience ecology, political ecology, and actor-network theory. It is applied to a case study of the Calicanto area (Cochabamba, Bolivia) with emphasis on the 1990-1993 period. Calicanto spate irrigation provided an effective landscape technology over more than 15 km² and 3500 fields via a 65-km canal network, thus comprising the largest spate-irrigated area of Latin America. Use of this irrigation technology was linked to climate variability and environmental variation as well as landscape features, livelihood diversification including widespread migration, and innovative high-agrobiodiversity land use, in addition to community resource management, settlement patterning, population density, and production intensity. Notwithstanding social-ecological resilience and versatility, the trajectory of this irrigation underwent major change with new waterworks launched in 1993. Key lessons for the related social-ecological sciences, development policy, and sustainability perspectives include: (i) versatility and viability of spate irrigation hinges on multiple social-ecological links; and (ii) its limitations include eclipse via irrigation trajectories lacking social-ecological analytic and conceptual capacities, and widespread albeit largely unacknowledged biases against the landscape technology of spate irrigation.     

Performance of the WRF model to simulate the seasonal and interannual variability of hydrometeorological variables in East Africa: a case study for the Tana River basin in Kenya

This study investigates the ability of the regional climate model Weather Research and Forecasting (WRF) in simulating the seasonal and interannual variability of hydrometeorological variables in the Tana River basin (TRB) in Kenya, East Africa. The impact of two different land use classifications, i.e., the Moderate Resolution Imaging Spectroradiometer (MODIS) and the US Geological Survey (USGS) at two horizontal resolutions (50 and 25 km) is investigated. Simulated precipitation and temperature for the period 2011–2014 are compared with Tropical Rainfall Measuring Mission (TRMM), Climate Research Unit (CRU), and station data. The ability of Tropical Rainfall Measuring Mission (TRMM) and Climate Research Unit (CRU) data in reproducing in situ observation in the TRB is analyzed. All considered WRF simulations capture well the annual as well as the interannual and spatial distribution of precipitation in the TRB according to station data and the TRMM estimates. Our results demonstrate that the increase of horizontal resolution from 50 to 25 km, together with the use of the MODIS land use classification, significantly improves the precipitation results. In the case of temperature, spatial patterns and seasonal cycle are well reproduced, although there is a systematic cold bias with respect to both station and CRU data. Our results contribute to the identification of suitable and regionally adapted regional climate models (RCMs) for East Africa.

     

Possible impacts of climatic warming scenarios on water resources in the Saskatchewan River Sub-basin,Canada

Regional scale studies of the impacts of global warming scenarios provide a useful mechanism for identifying potential regional sensitivities, data gaps and research needs, and for raising awareness of the global warming issue at the regional level. Thus, a pilot study of water resources in the Saskatchewan River Sub-basin was undertaken in order to provide first-cut estimates of impacts in this region, and to identify future research needs. Thirty scenarios were constructed, using two hypothetical growth rates for irrigation, five scenarios based on outputs from General Circulation Models (GCMs), and ten hypothetical warming scenarios. During the course of this study, a number of methodological questions were raised, including the representativeness of data points, interpolation of observed and scenario data, and the quantification of uncertainty.Results indicated decreases in summer soil moisture and increases in irrigation demand, but no consensus on changes in runoff or annual net basin supply, primarily due to differences in the GCM-based scenario output at the Rocky Mountains, the major source region for runoff. There were a number of recommendations for follow-up research and monitoring.     

江淮流域的旱涝研究

在江淮流域,梅雨等降水异常引发的旱涝经常发生。作者对江淮流域的灾害背景、气候特征及其影响因子等作了分析,发现在近50年中,降水有明显的年际和年代际异常,20世纪80年代以后,该区的降水有显著增加的趋势。典型旱涝年降水异常的时空分布表明,引起降水异常的因子非常复杂,即使在同一年中,不同月份的异常型也可能有差别。对于不同年份,降水异常型更为不同。影响江淮流域降水异常的因子的作用,可通过数值模拟进行“分离性” 研究,但由于模式的系统性误差,模拟结果也只有参考意义。因此,发展具有不同动力框架和热力过程的多种模式,仍是当前的重要任务。     

Climate Change Impact on Snow Coverage, Evaporation and River Discharge in the Sub-Arctic Tana Basin, Northern Fennoscandia

Arctic environments are generally believed to be highly sensitive to human-induced climatic change. In this paper, we explore the impacts on the hydrological system of the sub-arctic Tana Basin in Northernmost Finland and Norway. In contrast with previous studies, attention is not only given to river discharge, but also to the spatial patterns in snow coverage and evapotranspiration. We used a distributed water balance model that was coupled to a regional climate model in order to calculate a scenario of climate change by the end of this century. Three different model experiments were performed, adopting different approaches to using the climate model output in the hydrological model runs. The results were largely consistent, indicating a much shorter snow season and, accordingly, decreased sublimation, an increase in evapotranspiration, and a shift in the annual runoff peak. As the snow-free season is extended, the amount of solar radiation that is received during this period increases significantly. The results also show important local differences in the hydrological response to climate change. For example, in the scenario runs, the snow season was more than 30 days shorter at higher elevations, but in some of the river valleys, this was up to 70 days.     

Dams on the Mekong River: Lost fish protein and the implications for land and water resources

Proposed dam construction in the Lower Mekong Basin will considerably reduce fish catch and place heightened demands on the resources necessary to replace lost protein and calories. Additional land and water required to replace lost fish protein with livestock products are modelled using land and water footprint methods. Two main scenarios cover projections of these increased demands and enable the specific impact from the main stem dam proposals to be considered in the context of basin-wide hydropower development. Scenario 1 models 11 main stem dams and estimates a 4–7% increase overall in water use for food production, with much higher estimations for countries entirely within the Basin: Cambodia (29–64%) and Laos (12–24%). Land increases run to a 13–27% increase. In scenario 2, covering another 77 dams planned in the Basin by 2030 and reservoir fisheries, projections are much higher: 6–17% for water, and 19–63% for land. These are first estimates of impacts of dam development on fisheries and will be strongly mediated by cultural and economic factors. The results suggest that basic food security is potentially at a high risk of disruption and therefore basin stakeholders should be fully engaged in strategies to offset these impacts.     

气候资源变异对通河县相关产业的影响及对策

阐述了通河县48年的气候变异,采用气象学与其它学科相结合的方法,统计分析气候资源变异对当地相关产业的影响,并提出相应的对策。     

概论伊吾河洪水成因及其防御对策

根据伊吾河流域洪水类型及特点,分析了伊吾河暴雨的水汽来源、环流特征以及暴雨所形成的洪水灾害,并对伊吾河洪水的防御提出了工程性措施和非工程性措施。     

Materialising energy and water resources in everyday practices: Insights for securing supply systems

Policies to secure energy and water supplies from the impacts of climate change are currently being developed or are in place in many developed nations. Little is known about how these policies of security, and the systems of resource provision they prioritise, affect householders’ capacity to adapt to climate change. To better understand the connections between resource provision and consumption, this paper explores the notion that different ‘energies’ and ‘waters’ can be conceptualised as material elements of social practices, which shape the way practices are performed. We draw on a study of Australian migrants and their experiences with different resource provision systems in multiple countries, time periods and contexts across three generations. We discuss the differing characteristics of energy and water provision across three broad resource ‘eras’, and the way resources enable or reduce resourcefulness, adaptive capacity and resilience. We find that policy makers may inadvertently reduce householders’ capacity to respond and adapt to climate change impacts by prioritising the resource characteristics of immateriality, abundance and homogeneity. We conclude that policy which prioritises the resource characteristics of materiality, diversity and scarcity is an important, underutilised and currently unacknowledged source of adaptive capacity.     

长三角城市群非均匀性对区域热岛效应影响的数值模拟

使用中尺度数值模式WRF3.9/Noah/UCM,对长三角地区无明显天气过程的2013年8月11至17日一周进行数值模拟,采用2013年500 m分辨率的MODIS数据更新土地覆盖资料,依据城镇比例将城市下垫面进一步分类为高中低3种类型,以此研究长三角城市群非均匀性对区域热岛效应的影响。结果表明:长三角城市群近地面气象要素场对城市下垫面的非均匀性比较敏感,平均热岛强度、干岛强度和风速衰减相较于不考虑城市非均匀性分别减小了16.41%、20.04%和6.25%;受背景风场影响,白天城市群的热岛强度弱于夜晚,均有向下游扩展现象,且内陆城市的热岛强度和干岛强度较沿岸区域更强;相比于均匀城市下垫面试验,考虑非均匀城市影响后,整体热岛强度和干岛强度减弱;白天垂直热岛环流结构明显,整体可以伸展至2 km高度,在东南风背景下,热岛上游高密度城市的热岛环流会抑制下游热岛环流发展,考虑城市非均匀性后,上游效应更显著;热岛强度受非均匀性影响在傍晚和夜间最高减弱可达0.2℃,且进入较强热岛的时间会推迟,维持时间也将缩短。因此,忽略城市下垫面的非均匀性,可能会高估区域热岛效应。