大兴安岭天保工程区生态系统服务变化研究

利用Landsat和MODIS遥感数据和InVEST模型,评估了1990―2015年大兴安岭天保工程区实施前后生态系统土壤风蚀量、生境质量和碳储量的时空变化,并通过地理探测器方法对生态系统服务时空变化分布与趋势进行驱动因子探测和交互作用探测分析。结果表明：① 从空间分布来看,额尔古纳市南部、鄂温克族自治旗西北部、科尔沁右翼前旗的土壤风蚀量大,生境质量差,碳储量低。② 2000年天保工程实施之后,森林面积显著增加,土壤风蚀量减少1.14%,生境质量增加0.49%,碳储量减少幅度为0.12%,低于2000年以前的0.64%。③ 土壤风蚀量主要受植被类型、土壤类型的影响,生态系统类型、植被类型对生境质量、碳储量空间异质性的影响显著大于其他因素,海拔、坡度2种地形因子对土壤风蚀量、碳储量的解释能力很小。温度、降水2种气候因子对土壤风蚀量、生境质量和碳储量的解释能力不固定,但仍是不可或缺的因素。     

我国旅游地理研究格局及热点分析

以国家自然科学基金2000—2019年资助的560项旅游类课题为数据来源,对课题立项的时空分布、承担单位、负责人等进行统计分析,构建由6个主类和15个亚类组成的旅游地理问题分类体系,运用词频统计和内容分析法,总结我国旅游地理研究格局和热点发展态势。研究发现：2000年至2019年间,自然基金委对旅游类课题的资助力度不断加强,总体呈先缓慢、后迅速增长、再大幅提升后保持平稳发展的态势,资助空间分布呈“东高西低”的特点,课题依托单位明显优势集中,课题承担人则呈离散分布;旅游流、旅游产业发展、旅游交通等研究主题热度逐渐减弱,旅游者行为和感知、旅游的社会文化影响、旅游地空间、典型旅游地保护和开发、旅游生态环境等主题热度明显上升,在此基础上对各热点主题历年变化特征和规律进行归纳总结。本文更新和拓展了以往同类研究发现,对旅游学者进行研究选题和课题申报有参考和指导意义。     

农用地土壤中7种重金属可提取态的测定

该文以氯化钙溶液进行提取,采用电感耦合等离子体质谱法和原子荧光光谱法,测定农用地土壤中Cd,As,Pb,Cr,Cu,Zn,Ni等7种重金属可提取态,检出限在0.003~0.06 mg/kg之间。该方法用于4个可提取态质控样品的测定,测定值与推荐值基本相符,测定的相对标准偏差(n=8)在3.3%~9.1%之间。基于800余件农用地土壤样品的测定数据,对7种重金属可提取态与土壤pH值及重金属总量之间的关系进行了初步考察。结果表明,7个重金属可提取态和总量关系无明显相关性,仅在土壤酸性条件下可提取态Cd与总量Cd呈正相关性。7种重金属提取率大小顺序为Cd>Zn>Ni>Cu,As>Pb>Cr,其中Cd,Zn,Ni,Cu,Pb的提取率随土壤pH值的增大而迅速下降,而As,Cr在土壤碱性条件下的提取率略高于中酸性条件下的提取率。     

Spinning in circles? A systematic review on the role of theory in social vulnerability,resilience and adaptation research

An increasing number of publications focus on social vulnerability, resilience, and adaptation (SVRA) towards natural hazards and climate change. Despite this proliferation of research, a systematic understanding of how these studies are theoretically grounded is lacking. Here, we systematically reviewed 4432 articles that address SVRA in various disciplinary fields (e.g. psychology, sociology, geography, mathematics) for various hazards, including floods, droughts, landslides, storm surges, wildfires, tsunamis, earthquakes, and volcano eruptions. We focus on the extent to which these studies explicate the frameworks, theoretical constructs or theories they rely on. Surprisingly, we found that about 90% of the reviewed studies do not explicitly refer to a theoretical underpinning. Overall, theories focusing on individuals’ SVRA were more frequently used than those focusing on systems, society, groups, and networks. Moreover, the uptake of theories varied according to the hazard investigated and field of knowledge, being more frequent in wildfire and flood studies and articles published in social science journals. Based on our analysis, we propose a reflexive handling of theories to foster more transparent, comparable, and robust empirical research on SVRA.     

面向不同主题的交通大数据可视分析

大数据时代,交通数据如何更快更准确地实时反映交通状况成为研究热点。使用不同交通数据对不同的研究主题进行可视分析,进而揭示蕴含的交通信息知识,为交通部门提供决策支持。首先,分析了大数据的基本特征,总结了大数据可视分析的研究现状;其次,对交通大数据的基本构成、获取方式及数据类型特点进行详细描述;最后,按照不同的研究主题选择不同的数据源与不同的可视化表达方式,揭示不同研究主题蕴含的交通规律,为交通大数据的自动模型分析提供可靠的可视化知识。     

Urbanizing the nation-state? Notes on the geopolitical growth of cities and city-regions

This article suggests that the developments during the past few decades indicate a qualitative shift in the city/state relation, and conceptualizes this shift as the geopolitical growth of cities and city-regions. Originally a state-orchestrated process, today this is manifested in the attempts of major cities and city-regions, in particular, to demand a stronger national and international political role even as claims are made for urban separatism. This process is connected to a geopolitical reasoning of the heightened role of cities in inter-state competition during the age of post-Fordist capitalism. Furthermore, the geopolitical growth of cities and city-regions is partly constituted in academic theories and expert knowledges that combine certain type of urbanism, economic growth, and political success, and which in so doing destabilize state-centered geopolitical imaginations.     

基于HJ-1A高光谱影像的湿地精细分类

混合像元的存在不仅影响了基于高光谱影像的地物识别和分类精度,而且已成为遥感科学向定量化发展的主要障碍。本文以扎龙湿地为试验区,以环境一号卫星采集的高光谱影像为数据源,分别采用传统的全约束最小二乘光谱解混算法(fully constrained least squares spectral unmixing algorithm, FCLS)与基于稀疏约束最小二乘光谱解混算法(sparse constrained least squares spectral unmixing algorithm, SUFCLS)实现了试验区湿地的精细分类,并对两种分类结果的表现及其分类精度进行了对比分析。研究结果表明：SUFCLS算法能够自适应的从光谱库中选择场景中所占比例最高的一组端元,并将此端元的组合应用于传统的全约束最小二乘光谱解混中实现不同湿地类型丰度的提取,该算法充分考虑了端元的空间异质性,弥补了FCLS算法在端元选取过程中的不足。精度验证结果表明与FCLS算法相比,SUFCLS算法分类结果的均方根误差更小,丰度的相关系数更高,因此该方法对于提高湿地解混精度以及实现湿地精细化分类具有重要意义。     

The progress of human geography in China under the support of the National Natural Science Foundation of China

This paper analyzes the role of the National Natural Science Foundation of China (NSFC) in advancing human geography in China by focusing on five key research areas: land use, urban systems and urban agglomeration, economic globalization, climate change and social and cultural geographies. All NSFC-funded human geography programs related to these five topics from 1986 to 2017 comprise the sample for analysis, and the research topics, content, teams, and peer-reviewed journal publications supported by these programs are investigated. Specifically, this paper analyzes the NSFC’s promotion of the expansion of research topics in response to national developmental needs and the shifting frontiers of human geography research internationally, its enhancement of interdisciplinary research, and its contributions to the assembly of specialized research teams. The paper also reports important progress in Chinese human geography over the past 30 years through the institutional lens of the NSFC, revealing major characteristics and trends in the discipline. The paper concludes by calling for further collaboration between the research community and the NSFC for the development of a locally suitable and globally influential Chinese human geography.     

欺骗攻击环境下带有传感器故障的大规模电网分布式状态估计

本文研究了欺骗攻击环境下带有传感器故障的大规模电网分布式状态估计问题.通过引入拓扑关系来描述分布式传感器节点之间的相互关系,使用随机Bernoulli序列描述欺骗攻击模型及其随机特性.基于Lyapunov方法证明了带有传感器故障的系统在遭受欺骗攻击环境下的均方稳定及H_∞稳定的充分条件,并基于LMI设计了满足H_∞性能指标的分布式状态估计器.最后通过数值仿真验证了所设计估计器的有效性.     

Budgeting for climate change: obstacles and opportunities at the US state level

State governments in the United States are well placed to identify opportunities for mitigation and the needs for adaptation to climate change. However, the cost of these efforts can have important implications for budgets that already face pressures from diverse areas such as unfunded pensions and growing health care costs. In this work, the current level of spending on climate-related activities at the state level are evaluated and policy recommendations are developed to improve financial management practices as they relate to climate risk. An examination of state budgets reveals that climate mitigation and adaptation activities represent less than 1% of spending in most states. The data collection highlights the obstacles to collecting accurate spending data and the lack of budgetary and accounting procedures in place. More importantly, the difficulty in benchmarking these activities poses challenges for the analysis of state-level policies as well as planning and modelling future climate-related spending. Other policy contexts, including public pensions and infrastructure, can provide guidance on budgetary and accounting tools that may help states prepare for and more efficiently manage climate-related expenditures.

Key policy insights

• Climate change mitigation and adaptation will require substantial investments across many levels of government on a wide range of activities.

• Currently, US states are not clearly demarcating climate expenditures, hindering the identification of climate-related budgetary risks.

• In the absence of guidelines, these longer term fiscal outlays may remain chronically underfunded in favour of more near-term spending priorities.

• Establishing appropriate financial management and data collection practices is important for more sophisticated cost-effectiveness and policy analyses.