基于地表温度-植被指数特征空间的区域土壤水分反演

针对目前西北地区广泛存在的农业干旱问题,选取了新疆塔里木盆地北缘渭干河-库车河三角洲绿洲为研究区,选择云量较少的两幅TM影像,建立地表温度-植被指数特征空间。首先利用线性方程拟合了特征空间的上下边界,比较利用归一化植被指数(NDVI)建立的地表温度-植被指数特征空间Ts/NDVI和利用改进型土壤调整植被指数(MSAVI)构建的地表温度-植被指数特征空间Ts/MSAVI形状的差异,并计算得到两种温度植被干旱指数(Temperature vegetation dryness index-TVDI,分别为TVDIN和MTVDI)。对TVDI与同期野外不同深度的实测土壤重量含水量数据进行回归分析,建立TVDI估测土壤水分的经验模型并对模型进行验证。研究结果表明,TVDIN和MTVDI均能够反演表层土壤水分,其中MTVDI与土壤水分相关性比TVDIN与土壤水分相关性要高,MTVDI能够更好地反映区域土壤水分状况,是一种更有效的土壤水分监测方法,对农业干旱监测具有一定的科学依据。     

Banach空间中非扩张映像的强收敛性

在实光滑和一致凸Banach空间中通过引入广义度量投影,证明了一个关于非扩张映像的修正Mann迭代序列的强收敛性定理。目的是利用广义度量投影来修改Nakajo与Takahashi的迭代方案,并将Nakajo与Taka—hashi文中所对应的主要结果由Hilbert空间推广到实光滑和一致凸Banach空间。     

Automatic generation of the axial lines of urban environments to capture what we perceive

Based on the concepts of isovists and medial axes, we developed a set of algorithms that can automatically generate axial lines for representing individual linearly stretched parts of open space of an urban environment. Open space is the space between buildings where people can freely move around. The generation of the axial lines has been a key aspect of space syntax research, conventionally relying on hand-drawn axial lines of an urban environment, often called axial map, for urban morphological analysis. Although various attempts have been made towards an automatic solution, few of them can produce the axial map that consists of the least number of longest visibility lines, and none of them really works for different urban environments. Our algorithms provide a better solution than existing ones. Throughout this article, we have also argued and demonstrated that the axial lines constitute a true skeleton, superior to medial axes, in capturing what we perceive about the urban environment.     

Soil aggregate fraction 1-5 mm: An indicator for soil quality in rangelands

Aggregate size distribution affects the soil’s physical quality and fertility. Widely used aggregation indices include the size fractions <0.25 mm, >2 mm, and >8 mm, and the mean weight diameter of aggregates. A recent study from the semi-arid hilly rangeland of the Negev desert, Israel revealed considerable impact of the type of surface cover (shrub patches, trampling routes, and the remainder of the interpatch spaces) on these indices, but only limited impact of hillside aspect (north- vs. south-facing) and a small impact of livestock grazing. The aim of this study was to address the impact of these factors on the poorly studied mid-size aggregate fraction of 1-5 mm as a complementary index of the soil’s physical quality. The content and mean weight diameter of this fraction were analyzed by using the same set of soil samples. As a general trend, compared with the widely used aggregation indices, the content of this fraction was found to be more responsive to livestock grazing. Furthermore, both the content and mean weight diameter of this fraction were found to be highly responsive to type of cover. These effects reveal positive relationships between this fraction and the soil’s physical quality.     

淮河流域洪涝变化吸引子维数研究

淮河流域洪涝序列的功率谱表现出了较好的混沌谱特征,这是序列呈分形结构的内在原因。洪涝序列及其不同平滑序列的关联维数表明,序列平滑程度越大,关联维数越小,关联维数反映了序列所在系统的层次,是系统结构复杂性的重要量度,是 系统建模所需独立变量的控制参数。要恰当地描述淮河流域洪涝发生系数,需构造至少５个状态变量的动力学系统。     

A GEOGRAPHICAL ANALYSIS OF IMAGE INTERPRETATION METHODS

Image interpretation methods, procedures for relating image pattern to ground conditions, are essential to our use of remote sensing imagery. These methods can be analyzed in respect to the role of ancillary information in the image interpretation process. In general, those procedures that are comparatively independent of ancillary information can be applied in varied geographic settings. Because almost all interpretation procedures depend to some extent upon ancillary information, a detailed and integrated knowledge of the cultural and physical landscape is a prerequisite for both manual and automated interpretation procedures.     

城乡文化信息流时空整合的理论体系构建

为了探寻城乡文化信息流的基本规律,将综合运用大数据思维和Petri网理论,通过“3S”集成技术以及State flow分析工具,旨在解决如何测度城乡文化信息的流态关系和构建时空整合模型两个科学问题。从“动态”的城乡文化“场域”视野出发,以城乡文化信息流的时空整合为研究对象,探索文化信息流对新城乡文化空间形成的影响,并研制出驱动机理和时空整合模式,初步构建现代城乡文化信息流的时空整合理论,力图为促进新文化地理学和信息社会学等多学科的交融发展创建新的理论菜单,为加快城乡文化一体化发展奠定理论基础,为中国城乡文化信息资源共享工程的可持续建设提供科学理论支撑。     

粤港澳大湾区协同创新的综合测度与演化特征

理解粤港澳大湾区协同创新的网络结构及其演化特征对于新时期大湾区的创新化发展转型至关重要。论文通过构建包括技术创新、知识生产、创新资本3个维度的协同创新测度指标体系,基于城市群流空间网络构建与社会网络分析方法,系统性研究了多创新维度下粤港澳大湾区协同创新的网络结构及其演化特征。结果表明：(1)粤港澳大湾区创新流空间结构呈现出显著的极化特征,且随着时间推移,极化效应不断强化,深圳、香港、广州在创新流空间网络中占据绝对核心地位;(2)多维度创新流要素网络结构呈现出显著差异性,技术创新与创新资本维度中,香港、深圳占据了城市群网络的核心,知识生产维度的核心城市则是广州与香港,广州在各维度网络中均扮演了重要的“枢纽型”城市角色,深圳在各维度网络中的创新层级随着时间推移在不断增长;(3)综合多维度指标的测度结果显示,香港与深圳分别是早期与新时期粤港澳大湾区协同创新网络的核心,当前大湾区整体呈现为穗深港三核心并立的城市群网络空间结构。研究可为新时期粤港澳大湾区创新资源的合理化配置提供理论与实证支撑。     

Uncertainty analysis of space–time prisms based on the moment-design method

Space–time prism (STP) is an important concept for the modeling of object movements in space and time. An STP can be conceptualized as the result of the potential path of a moving object revolving around in the three-dimensional space. Though the concept has found applications in time geography, research on the analysis and propagation of uncertainty in STPs, particularly under high degree of nonlinearity, is scanty. Based on the efficiency and effectiveness of the moment-design (M-D) method, this paper proposes an approach to deal with nonlinear error propagation problems in the potential path areas (PPAs) of STPs and their intersections. Propagation of errors to the PPA and its boundary, and to the intersection of two PPAs is investigated. Performance of the proposed method is evaluated via a series of experimental studies. In comparison with the Monte Carlo method and the implicit function method, simulation results show the advantages of the M-D method in the analysis of error propagation in STPs.     

2000年以来中国社会地理学发展的回顾与展望

2000年以来,中国社会地理学呈现出良好的发展态势。梳理和分析该时期中国社会地理学的发展,对了解当前国内本学科的现状和指导未来一段时期的发展都具有重要意义。首先对社会地理学的发展进行简要介绍,探讨了社会地理学的研究主题。通过对大量文献和著作的梳理,在对2000年以来中国社会地理学发展的总体分析基础上,从城市社会地理学与乡村社会地理学两方面对社会地理学研究的主要内容进行了归纳和评述,最后对中国社会地理学未来的发展进行了讨论和展望。在未来的学科建设与研究中,中国社会地理学应积极合理地借鉴西方地理学与其他学科优秀成果,继续拓展并深化已有的研究内容,探索建立具有中国特色的社会地理学理论框架,同时发挥社会地理学问题指向性优势,提高解决实际问题的能力。