The evolution of the spatial-temporal patterns of global energy security since the 1990s     

Wang  Qiang  Xu  Linglin  Li  Na  Du  Xue  Wu  Shidai  Tian  Lanlan  Wu  Chenlu 《地理学报(英文版)》2019,29(8):1245-1260

Journal of Geographical Sciences - In this study, we developed an energy security evaluation model (ESEM) from three dimensions, energy supply-transport security, safety of energy utilization, and...  相似文献   

河湖水系连通理论基础与优先领域     

李宗礼  刘昌明  郝秀平  邱冰  王中根 《地理学报》2021,76(3):513-524

河湖水系连通是中国正在推进的重大治水战略,是提高国家水资源统筹调配能力、水生态环境修复能力和河湖健康保障能力的重大举措,也是提高水旱灾害抵御能力的重要保障。目前河湖水系连通的知识比较零散,尚未形成系统的理论体系,河湖水系连通理论基础的研究,对理论体系的构建、战略的实施和持续推进具有重要意义。本文基于河湖水系连通的理论研究的特征,提出其理论框架体系,分析了可持续发展、水利科学、经济学、生态学、系统科学等基础理论与河湖水系连通理论体系之间的内在关系。从当前国家实施河湖水系连通战略和构建河湖水系连通理论体系的迫切需求出发,本文提出了河湖水系连通理论研究的优先领域,包括河湖水系连通性与功能评价理论与方法、河湖水系连通水体耦合机制与系统稳定性理论、水系连通协调性理论、水系连通—经济格局匹配性理论、水系连通—生态环境影响机理与评估理论、水系连通巨系统不确定性与适应性理论等,优先突破重点领域理论研究,逐步形成和完善河湖水系连通理论体系,以科学、完整的理论体系支撑河湖水系连通治水战略高效、顺利实施。  相似文献   

Optimal rural land use allocation in central China: Linking the effect of spatiotemporal patterns and policy interventions     

《Applied geography (Sevenoaks, England)》2017

Rural land use development is experiencing a transition stage of socioeconomic and land use development in China. Historic land use transition process and policy interventions have key influence on the applicability of land use allocation solutions in future land use management. Strategic land use allocation is therefore required to possess a good adjustment capability to the transition process. Although heuristic optimization methods have been promising to solve land use allocation problems, most of them ignored the spatially explicit effect of historic land use transition and policies. To help resolve this issue, this study aims to optimize future land use pattern in the context of rural land use development. We took Yunmeng County, one of the typical major grain producing and rapidly urbanizing areas in central China, as a case study and solved the sustainable land use allocation problem by using an improved heuristic optimization model. The model was constructed based on the integration of a spatial discrete particle swarm optimization and cellular automata-Markov simulation approach. The spatiotemporal land use patterns and policy interventions were represented by the CA-Markov as in spatially explicit transition rules, and then incorporated into the discrete PSO for optimal land use solutions. We examined the influence of the joint effect of spatiotemporal land use patterns and policy interventions on the land use allocation outcome. Our results demonstrate the robustness and potential of the proposed model, and, more importantly, indicate the significance of incorporating the spatiotemporal land use patterns and policy interventions into rural land use allocation.  相似文献   

国外土地配置研究与启示     

唐莹 《地域研究与开发》2017,36(2)

总结国外土地配置研究的特点与经验,可以为我国土地配置工作面临的诸多新问题与新挑战提供参考与借鉴。利用文献资料法与定性分析法,对国外有关土地配置的研究进行了梳理和分析。国外土地配置研究对维持生态系统正常运行、保护土地景观、阻止生态用地向工业用地过度转化以及确保土地利用社会整体利益最大化等问题非常关注,对土地适宜性评判、不同因素对土地配置的影响及土地配置调控手段效率检验与改进等方面也进行了比较深入的研究。与国外土地配置研究相比,我国土地配置研究应从扩展研究视角、注重多维度土地利用类型的适宜性评判、重视利益主体诉求以及探析土地配置新途径等方面完善相关研究体系。  相似文献   

A Time Monte Carlo method for addressing uncertainty in land-use change models     

Ahmed Mustafa  Ismaïl Saadi  Mario Cools  Jacques Teller 《International journal of geographical information science》2018,32(11):2317-2333

One of the main objectives of land-use change models is to explore future land-use patterns. Therefore, the issue of addressing uncertainty in land-use forecasting has received an increasing attention in recent years. Many current models consider uncertainty by including a randomness component in their structure. In this paper, we present a novel approach for tuning uncertainty over time, which we refer to as the Time Monte Carlo (TMC) method. The TMC uses a specific range of randomness to allocate new land uses. This range is associated with the transition probabilities from one land use to another. The range of randomness is increased over time so that the degree of uncertainty increases over time. We compare the TMC to the randomness components used in previous models, through a coupled logistic regression-cellular automata model applied for Wallonia (Belgium) as a case study. Our analysis reveals that the TMC produces results comparable with existing methods over the short-term validation period (2000–2010). Furthermore, the TMC can tune uncertainty on longer-term time horizons, which is an essential feature of our method to account for greater uncertainty in the distant future.  相似文献   

Ecosystem Carbon Allocation of a Temperate Mixed Forest and a Subtropical Evergreen Forest in China     

LUO Yiwei  ZHANG Leiming  GUO Xuebing  DAI Guanhua  WANG Anzhi  ZHOU Guoyi  YU Guirui 《资源与生态学报(英文版)》2018,9(6):642-653

Ecosystem carbon allocation can indicate ecosystem carbon cycling visually through its quantification within different carbon pools and carbon exchange. Using the ecological inventory and eddy covariance measurement applied to both a mature temperate mixed forest in Changbai Mountain (CBM) and a mature subtropical evergreen forest in Dinghu Mountain (DHM), we partitioned the ecosystem carbon pool and carbon exchange into different components, determined the allocation and analyzed relationships within those components. Generally, the total carbon stock of CBM was slightly higher than that of DHM due to a higher carbon stock in the arbor layer at CBM. It was interesting that the proportions of carbon stock in vegetation, soil and litter were similar for the two mature forests. The ratio of vegetation carbon pool to soil carbon stock was 1.5 at CBM and 1.3 at DHM. However, more carbon was allocated to the trunk and root from the vegetation carbon pool at CBM, while more carbon was allocated to foliage and branches at DHM. Moreover, 77% of soil carbon storage was limited to the surface soil layer (0-20 cm), while there was still plentiful carbon stored in the deeper soil layers at DHM. The root/shoot ratios were 0.30 and 0.25 for CBM and DHM, respectively. The rates of net ecosystem productivity (NPP) to gross ecosystem productivity (GPP) were 0.76 and 0.58, and the ratios of ecosystem respiration (Re) to GPP were 0.98 and 0.87 for CBM and DHM, respectively. The net ecosystem carbon exchange/productivity (NEP) was 0.24 t C ha^-1 yr^-1 for CBM and 3.38 t C ha^-1 yr^-1 for DHM. Due to the common seasonal and inter-annual variations of ecosystem carbon exchange resulting from the influence of environmental factors, it was necessary to use the long record dataset to evaluate the ecosystem sink capacity.  相似文献   

面向估计性能的双通道带宽分配策略研究     

彭志荣  赵瞩华  陈惠珍  李伟雄  陈相德 《南京气象学院学报》2021,13(4):502-508

本文主要研究了面向估计性能的双通道带宽分配策略问题.为了减小网络化控制系统中时滞现象对信号传输的影响,将系统建模为Markov跳变时滞系统.采用双通道传输策略,提升数据到达率,减少数据包的丢失.考虑到信道容量的有限性不利于大量数据的高效传输,将有限的带宽灵活地分配于两个通道,使得信道容量得到充分利用.在此基础上,本文提出了面向估计性能的双通道带宽分配策略,设计了双通道量化传输方案以及状态估计器,推导出了时变估计误差系统满足H_∞性能的充分条件,并得出估计器增益矩阵设计方法,最后给出实例验证了所设计系统的有效性.  相似文献   

构建广西特色旅游业的优势与对策思路   总被引：1，自引：0，他引：1  

郝革宗 《热带地理》1999,19(3):230-234

改革开放以来,广西旅游业发展迅速,进入９０ 年代,增长速度减缓,呈现波浪式前进的趋势。目前广西正对旅游发展战略进行调整,积极构建广西特色旅游业。构建广西特色旅游业拥有很多优势：广西区位条件良好,自然风光秀丽,人文景观丰富,并已拥有比较完整的旅游服务体系。今后在构建广西特色旅游业中,急需加强政府的引导作用,把旅游业作为广西一项支柱产业来看待;注意发挥广西旅游资源优势,积极推出一批特色鲜明的旅游产品;建设布局合理的旅游产业格局,使广西规划中的４ 个旅游区的旅游产品各具特色,功能相互补充,结构层次相互协调;积极参加全国旅游网络的协作,力争今后有更快的发展  相似文献   

Coupling land use allocation models with raster GIS   总被引：5，自引：0，他引：5  

Robert G. Cromley  Dean M. Hanink 《Journal of Geographical Systems》1999,1(2):137-153

As geographic information systems (GIS) have moved from information storage and retrieval operations towards more decision support functions, there is a need for more integration of spatial analytical modules that can assist in locational decisions. This paper presents a methodology for coupling land use allocation models with a raster GIS. For raster systems, the integration of any decision module has been limited by the size of raster datasets that may contain hundreds of thousands of pixels. Therefore, decision heuristics have been used rather than exact methods such as mathematical programming models. For the problem of land use allocation, the special structure of the generalized assignment problem is used here to handle large scale datasets. The advantage of the mathematical programming approach is the additional information associated with the dual variables and opportunity costs that can be used in subsequent sensitivity analyses. Received: 7 April 1998/Accepted: 2 October 1998  相似文献   

绿潮迁移过程中环境要素与浒苔藻体生物学特征的相关性分析     

管晨  郝雅  侯承宗  唐学玺  王影 《海洋与湖沼》2021,52(1):114-122

浒苔(Ulva prolifera)引起的大规模绿潮起源于黄海南部,在向北迁移过程中生物量迅速扩增,在海州湾附近(35°N左右)迅速增加达到峰值。在绿潮漂浮迁移过程中,海水表层温度、溶解无机氮(dissolved inorganic nitrogen,DIN)和磷酸盐(PO4^3-P-)变化显著。本文以迁移过程中的浒苔为研究对象,分析了环境要素变化与浒苔藻体的生物学特征间的关系。结果显示,随着绿潮的漂浮迁移,浒苔藻体光系统Ⅱ最大光化学量子产量Fv/Fm从0.7逐渐降低至0.45左右,光系统Ⅱ实际光化学量子产量Y(Ⅱ)从0.55逐渐降至0.25左右;硝酸还原酶活性(nitrate reductase activity,NRA)从2.7μmol/L NO2^-/(mg·h)降至0.5μmol/L NO2-/(mg·h)左右;生殖分配率(RA)从15%逐渐上升至50%左右。相关性分析表明,DIN与浒苔藻体的生物学特征相关性呈极显著,表明在漂浮迁移中,DIN对浒苔的生物学特征至关重要。温度对浒苔藻体光合活性和NRA的影响极显著;光照强度对浒苔藻体光合活性的影响极显著,对NRA的影响显著;盐度和PO4^3--P显著影响浒苔藻体的光合活性和NRA,而这四种环境要素与浒苔形成生殖细胞的相关性不显著。本文认为,绿潮漂浮迁移过程中,浒苔藻体光合活性、营养盐吸收等生物学特征对环境中DIN的变化响应最敏感,其他环境要素对浒苔藻体的影响程度大小依次为温度、PO4^3--P、盐度和光照强度。绿潮漂浮迁移过程中环境要素的变化直接影响了浒苔的生长与生殖,尤其是海州湾附近(35°N左右)是浒苔藻体状态改变的分水岭。  相似文献