空间信息网格中动态复制策略的研究

空间信息网格项目数据量大，用户遍及各地，对数据文件的请求延时大、占大量带宽。复制可以节省带宽、减少时延、均衡负载、改善系统可靠性。采用动态复制技术可以使用户有效地获得所需的数据。详细地论述了动态复制策略以及空间信息网格中的复制管理机制、复制服务流程和具体实施。     

Revised runoff curve number for runoff prediction in the Loess Plateau of China

The soil conservation service (now Natural Resources Conservation Service) Curve Number (SCS-CN), one of the most commonly used methods for surface runoff prediction. The runoff calculated by this method was very sensitive to CN values. In this study, CN values were calculated by both arithmetic mean (CN_C) and least square fit method (CN_F) using observed rainfall-runoff data from 43 sites in the Loess Plateau region, which are considerably different from the CN₂ values obtained from the USDA-SCS handbook table (CN_T). The results showed that using CN_C instead of CN_T for each watershed produce little improvement, while replacing CN_T with CN_F improves the performance of the original SCS-CN method, but still performs poorly in most study sites. This is mainly due to the SCS-CN method using a constant CN value and discounting of the temporal variation in rainfall-runoff process. Therefore, three factors—soil moisture, rainfall depth and intensity—affecting the surface runoff variability are considered to reflect the variation of CN in each watershed, and a new CN value was developed. The reliability of the proposed method was tested with data from 38 watersheds, and then applied to the remaining five typical watersheds using the optimized parameters. The results indicated that the proposed method, which boosted the model efficiencies to 81.83% and 74.23% during calibration and validation cases, respectively, performed better than the original SCS-CN and the Shi and Wang (2020b) method, a modified SCS-CN method based on tabulated CN value. Thus, the proposed method incorporating the influence of the temporal variability of soil moisture, rainfall depth, and intensity factors suggests an accurate runoff prediction for general applications under different hydrological and climatic conditions on the Loess Plateau region.     

The impact of biofuel-induced food-price inflation on dietary energy demand and dietary greenhouse gas emissions

Dramatic increases in liquid biofuel production have led to concerns about associated impacts on food prices, with many modeling studies showing significant biofuel-related price inflation. In turn, by changing patterns of food demand, biofuel production may indirectly influence greenhouse gas emissions. We estimated changes to dietary energy (calorie) demand and greenhouse gas emissions embodied in average diets under different biofuel-related food-price scenarios for Brazil, China and the United States, using food-price projections and food-price elasticities. Average energy demand decreased in all countries, from about 40 kcal per person per day in Brazil under a moderate price inflation scenario – a reduction of 1% relative to the (2009) reference scenario – to nearly 300 per day in the United States with high price inflation – almost 8% of reference levels. However, emissions per calorie increased slightly in all three countries. In terms of total greenhouse gas emissions, the results are suggestive of overall reductions only in the United States, where average reductions ranged from about 40 to 110 kg of carbon dioxide equivalent emissions per person per year. In China, the direction of impact is unclear, but the net change is likely to be small. Brazilian results were sensitive to parameter values and the direction and magnitude of impact is therefore uncertain. Despite the uncertainty, even small changes (positive or negative) in individual dietary emissions can produce large changes at the population level, arguing for the inclusion of the dietary pathway in greenhouse gas accounting of liquid biofuels.     

An asynchronous Geoprocessing Workflow and its application to an Antarctic ozone monitoring and mapping service

The integration of Sensor Web Enablement services with other Open Geospatial Consortium (OGC) Web Services as Geospatial Processing Workflows (GPW) is essential for future Sensor Web application scenarios. With the help of GPW technology, distributed and heterogeneous OGC Web Services can be organized and integrated as compound Web Service applications that can direct complicated earth observation tasks. Under the Sensor Web environment, asynchronous communications between Sensor Web Services are common. We have proposed an asynchronous GPW architecture for the integration of Sensor Web Services into a Web Service Business Process Execution Language workflow technology. We designed a Sensor Information Accessing and Processing workflow, an asynchronous GPW instance, to take an experiment of observing and mapping ozone over Antarctica. Based on our results, our proposed asynchronous workflow method shows the advantages of taking environmental monitoring and mapping tasks.     

On predicting and improving the quality of Volunteer Geographic Information projects

Initiatives that rely upon the contributions of volunteers to reach a specific goal are growing more and more with the success of Web 2.0–interactive applications. Also scientific projects are testing and exploiting volunteers' collaboration, but the quality of information obtained with this approach is often puzzling. This paper offers a rich overview of many scientific projects where geographic contributions are committed to volunteers, to the aim of defining strategies to improve information quality. By describing real examples of Volunteer Geographic Information (VGI), the contribution establishes a categorization based on the characteristics of the information, tasks, and scopes of the projects. After a discussion on the relationships of categories and VGI quality, the paper analyses techniques to improve the quality of volunteered information according to the moment of its assessment (i.e., ex ante, ex post, or both with respect to information creation). The paper outlines the main limitations of the different approaches and indicates some guidelines for future developments.     

Knowing wildfire risk: Scientific interactions with risk mitigation policy and practice in Victoria,Australia

Over the past decade, major landscape wildfires (or ‘bushfires’ in Australia) in fire-prone countries have illustrated the seriousness of this global environmental problem. This natural hazard presents a complex mesh of dynamic factors for those seeking to reduce or manage its costs, as ignitions, hazard behaviour, and the reactions of different human and ecological communities during and after hazard events are all extremely uncertain. But while those at risk of wildfire have been subject to significant research, the social dimensions of its management, including the role of science, have received little attention. This paper reports on a case study of the Barwon-Otway area of Victoria in Australia, a high wildfire risk area that has recently been a pilot site for a new risk mitigation strategy utilising the wildfire simulation model PHOENIX RapidFire. Against simple equations between ‘more science’ and ‘less uncertainty,’ this paper presents results from interviews and a workshop with practitioners to investigate how scientific research interacts with and informs both wildfire policy and practice. We suggest that attending to cultural and social specificities of the application of any technical innovation—such as next generation modelling—raises questions for future research about the roles of narrative, performance, and other knowledges in the sedimentation of science.     

The public trust doctrine and critical legal geographies of water in California

Legal processes shape how water resources are allocated, regulated, distributed, and governed. This paper examines the public trust doctrine, a legal principle that addresses the state’s role in governing natural resources by requiring states to manage certain bodies of water and their shorelines for the good of the public. The paper focuses on how the public trust doctrine has been used—with varying degrees of success—to protect water bodies by contesting the diversion and transfer of water in California. The paper compares how the doctrine was applied in two cases: Mono Lake and the Salton Sea, two California lakes that have been threatened by water diversions and transfers. Advocates at Mono Lake successfully used the public trust doctrine for environmental protection, while public trust was an unsuccessful strategy at the Salton Sea. The paper examines issues of nonequilibrium ecosystems, natural versus artificial ecosystems, and wasteful versus reasonable uses of water.By investigating why one case was deemed eligible for public trust protections while the other was not, this paper examines how discursive constructions of nature are embedded in and enacted by legal institutions and how these constructions of nature impact the implementation of legal protections of natural resources. In examining the use of the public trust doctrine in California, the paper examines both the potential and the limitations of the public trust in practice, showing how legal processes and institutions can be used to protect public interests in natural resources but also how particular environmental narratives are reinforced through these institutions.     

Public views on economic growth,the environment and prosperity: Results of a questionnaire survey

The long-standing academic and public debate on economic growth, prosperity and environmental sustainability has recently gained new momentum. It lacks, however, a broad perspective on public opinion. Prior opinion surveys typically offered a simple dichotomous choice between growth and environmental protection. This study examines public beliefs and attitudes about a wider range of aspects of the growth debate. To this end, we conducted an online questionnaire survey including a country-wide, representative sample of 1008 Spanish citizens. Using factor analysis, we identify six distinct dimensions of public attitudes, referred to as: prosperity with growth; environmental limits to growth; general optimism; wrong priority; overrated GDP; and governmental control. We further analyze several specific questions associated with the growth debate, such as those concerning the desired GDP growth rate, the preferred growth-environment position, and beliefs about, as well as reasons for, a possible end or continuation of growth. We find that most respondents favor GDP growth rates of more than 3%. A majority views growth and environmental sustainability as compatible (green growth), while about one-third prefers either ignoring growth as a policy aim (agrowth), or stopping it altogether (degrowth). Only very few people want growth unconditionally (growth-at-all-costs). About one-third of the respondents believe that growth may be never-ending. We examine how support for or disagreement with different statements on growth are related to each other, as well as how they are influenced by socio-demographic, knowledge and ideology/values variables. Overall, our findings can inform public debates about the growth paradigm and its potential alternatives by providing a more nuanced understanding of public opinion. We make suggestions for future research, including modifying poll questions on growth and environment through offering a more diverse set of response options.     

塔西台地寒武纪沉积环境演化与海陆耦合

碳酸盐岩台地作为陆地与深海间的过渡带,其沉积记录了海洋和邻近陆地的演化。结合已有的沉积学工作,对塔里木盆地西部台地寒武系碳酸盐岩进行全岩及酸不溶物地球化学研究。塔西台地寒武纪主要发育局限台地、局限-蒸发台地或蒸发台地相沉积。碳酸盐岩的地球化学特征主要受沉积环境和成岩作用影响,对研究区寒武系白云岩来说,其元素组成极易受沉积微相的控制,氧同位素组成则很可能已被成岩作用改造,仅原生、准同生白云岩的Sr/Ba、Fe/Mn和C同位素可反映沉积相演化对应的古盐度、离岸距离等沉积环境特征的变化,酸不溶物化学蚀变指数（CIA值）则指示邻近陆地的化学风化强度与气候特征。寒武纪时期,塔西台地在相对海平面较高时发育局限台地相沉积,以水体盐度较低、沉积环境离岸较远和生物活动相对较弱为特征,陆地化学风化强度适中,气候温暖湿润;在相对海平面较低时发育蒸发台地相沉积,具有水体盐度较高、沉积环境离岸较近和生物活动相对较强等特点,陆地化学风化强烈,气候炎热极端;在相对海平面适中时发育局限-蒸发台地,沉积环境和邻近陆地的特征介于前述二者之间。沉积相演化对应的较长周期的海陆演化可能主要受全球海平面升降及宏观气候变化控制,具体表现为相对海平面升降所导致的海相沉积环境的变化,以及气候变化引起的陆地化学风化强度的变化。寒武纪塔西台地所处区域的海洋-陆地演化具有高度耦合的特征。     

Application of ICTs in Airspace Management and Collaborative Decision-Making—Analyzing the Risk Avoidance in the Condition of Risky Weather as an Example

The application of ICTs makes structural change of the development and effective utilization of airspace. Next generation air transportation system (NextGen) includes new automation concepts with automated information to support the traffic control decision-making. As a result, in the field of academia and industry, air traffic controllers integrate information automatically while making decisions to change the previous manually integrated and decided pattern. The safety ability of airspace is reduced and airspace system is endangered under risky weather conditions of airspace. So there is an urgent demand for new information and communication technologies. The paper is an overview of the information constitution and support of NextGen and provides the study of the development of technique of airspace collaborative decision-makings to confirm the new features based on ICTs. It contains basic application-the input of data and output of the routes of airspace management and collaborative decision-making, and general application-the choose of probability nets of avoiding risky weather, and special application-the affection in the management of the air routes, which are made up of position and direction. The research shows the accurate schedule characteristics of airspace management and collaborative decision-making based on ICTs, which made the space accurate by time accurate. Second, the visualization of airspace management and collaborative decision-making based on ICTs made the maps of flight path under mobile data quickly generated. This could make the fully development and utilization of national airspace, ensure safety, and reduce air traffic controllers’ workload and the costs in delaying and operating in risky weather.