Simulation of landscape spatial layout evolution in rural-urban fringe areas: a case study of Ganjingzi District

In recent years, the rapid expansion of urban spaces has accelerated the mutual evolution of landscape types. Analyzing and simulating spatio-temporal dynamic features of urban landscape can help to reveal its driving mechanisms and facilitate reasonable planning of urban land resources. The purpose of this study was to design a hybrid cellular automata model to simulate dynamic change in urban landscapes. The model consists of four parts: a geospatial partition, a Markov chain (MC), a multi-layer perceptron artificial neural network (MLP-ANN), and cellular automata (CA). This study employed multivariate land use data for the period 2000–2015 to conduct spatial clustering for the Ganjingzi District and to simulate landscape status evolution via a divisional composite cellular automaton model. During the period of 2000–2015, construction land and forest land areas in Ganjingzi District increased by 19.43% and 15.19%, respectively, whereas farmland, garden lands, and other land areas decreased by 43.42%, 52.14%, and 75.97%, respectively. Land use conversion potentials in different sub-regions show different characteristics in space. The overall land-change prediction accuracy for the subarea-composite model is 3% higher than that of the non-partitioned model, and misses are reduced by 3.1%. Therefore, by integrating geospatial zoning and the MLP-ANN hybrid method, the land type conversion rules of different zonings can be obtained, allowing for more effective simulations of future urban land use change. The hybrid cellular automata model developed here will provide a reference for urban planning and policy formulation.     

西安曲江新区移民群体的地方意义建构与检验

处于变革时代的移民群体正经历着“回不去的乡村,融不进的城市”的挑战,构建地方意义以促进移民群体更好地适应迁入地,成为流动性视角下地方研究的基础性与迫切性课题。本文引介地方意义的概念,在系统梳理相关文献的基础上,选择西安曲江新区为案例地,借由理论建构和实证检验的逻辑思路,对曲江新区移民群体的地方意义展开实证探讨。研究发现:移民群体地方意义的探索性理论模型包括自我认同、人地互动、人际互动和综合互动4个维度,互动过程发生在由自然、社会关系与价值构成的关系性地理架构之上;本文开发的移民群体地方意义测量量表,包含4个维度共计20个问项,经过探索性因子分析和验证性因子分析,验证了所建构模型的稳定性和适切性。此外,本文还对地方意义的实质、识别与形成的特点展开了讨论。本研究充实并完善了“地方”及“地方意义”的概念体系结构,部分回应了移民与人地关系研究的理论延伸与发展需要。     

滨海城市竖向避难场所选址可靠性评价与若干问题探讨

关注滨海城市竖向避难场所的选址可靠性问题,首先深化确立“竖向避难场所”概念;然后构建竖向避难场所选址可靠性评价模型,综合自然地理要素和建成环境要素,从与灾害直接作用相关的选址暴露性、与应急交通相关的选址敏感性、与应急服务相关的选址适应性3个维度展开,搭建3级评价指标体系;再以天津滨海新区为例、聚焦滨海城市潮洪灾害和人口安全矛盾的集核——临港城区展开实证研究,借助ArcGIS分类与可视化发现：高低可靠性选址之间具有明显的空间分异,可以分解为灾害暴露性的“近岸高?远岸低”分异、交通敏感性的“外围高?中心低”分异、服务适应性的“中心与沿河高?外围低”兼“近港高?远港低”分异。同时发现：商业设施用地选址价值较高,在高可靠性选址中占比第一;中小学和社会福利设施用地选址价值最高,在高可靠性选址中占比第二;文化科研和娱乐康体设施用地在高可靠性选址中占比最小。针对临港城区实证研究结果,提出滨海城市竖向避难场所选址及可靠性提升对策。     

干旱荒漠区土地利用方式快速转变对土壤入渗性能的影响

研究不同土地利用类型下土壤入渗及其影响因素,有助于城市土地利用管理及径流调节。以快速城市化的兰州新区6种土地利用类型为例,利用圆盘入渗仪,对土壤水分入渗过程进行了实地测量,并利用主成分分析对影响因素进行研究。结果表明：城市化过程中土地利用变化使土壤砂粒和容重增加,总孔隙度和饱和含水量降低;待建地和人工林地的土壤入渗参数值均低于其他土地利用类型。土壤入渗率与有机质含量、总孔隙度、饱和含水量、粉粒含量正相关,与容重和砂粒、黏粒含量负相关。城市化过程中土地利用类型向待建地的转变改变了土壤理化性质及土壤水分入渗能力。     

雅安市雨城区壶穴形态特征

以雅安市雨城区的严桥河和周公河流域的河床壶穴为研究对象,对128处壶穴形态规模与几何参数进行详细测量。运用定量统计方法分析壶穴的分布规模和形态特征。结果表明:周公河流域壶穴大多分布在岸边大石块上,严桥河流域壶穴主要分布于河床的岩坎上;两地壶穴平均分布密度为0.43个/m2,相对其他区域较小,且壶穴的长短轴和平均口径与深度都有相对明显的规律。在平面形态上,壶穴形态多样,周公河以近圆型壶穴最多,占52.5%,严桥河以椭圆型壶穴最多,占63.6%。在垂直剖面形态上,周公河处壶穴90%属于U型,其余为V型;严桥河处壶穴V型和U型分别占52.3%和44.3%,还有3.4%属倒Ω型;两地壶穴都以浅型为主。     

三峡库区地质背景对土壤元素分布的影响及地方病效应

利用多目标地球化学调查方法,通过野外实地调查、大面积系统采集土壤表层样品、测试分析、数理统计,探讨了三峡库区灰岩母岩区与泥岩母岩区两种不同母岩条件下土壤中52个元素的含量分布特征。结果表明:三峡库区灰岩母岩区土壤元素富集而泥岩母岩区土壤元素贫乏,As、Br、B、Sb、C、F、I、Li、Mo、CaO等元素在灰岩母岩区土壤中含量大于泥岩区2倍以上。泥岩母岩区土壤元素含量比灰岩母岩区高的元素仅有Ba、P、Sr、Na₂O、SiO₂。元素分布的差异与三峡库区的地氟病与克山病分布关系密切,地氟病高发区主要分布于灰岩母岩风化形成的高氟土壤区,克山病则主要发生于泥岩母岩风化形成的低硒土壤区。地质背景对地方性疾病具有明显的区域控制作用,研究成果为三峡库区农业及城乡的合理规划布局提供了参考依据。     

海南岛北部全新世最大海侵古岸线的发现及其意义

全新世大暖期的最大海侵对沿海地区具有深刻影响,但是海南岛北部全新世的最大海侵范围研究较少。本研究利用高精度DEM数据解译以及野外钻探验证,发现海南岛北部全新世精确的最大海侵古岸线空间展布位置,其总面积约260 km²,其中约115 km²属于现今的江东新区规划建设范围内,占整个江东新区规划面积的38%。海南岛北部全新世最大海侵古海岸线的发现,不仅对理解南海全新世高海平面特征及规律提供琼北地区新证据,并且对海南自贸区(江东新区)应对未来海平面升高问题提供背景参照。     

A 200-year precipitation index for the central English Lake District / Un indice de précipitation de 200 ans pour la Région des Lacs en Angleterre

Abstract

Abstract The geographical context and hydroclimatology of the English Lake District means that the region is an important monitor of changes to nationally significant environmental assets. Using monthly rainfall series for sites in and around the central Lake District, a continuous ~200-year precipitation index was constructed for a representative station close to Grasmere. The bridged series shows a significant decline in summer rainfall since the 1960s, offset by increases in winter and spring that are strongly linked to North Atlantic forcing. Over longer time periods, the index exhibits several notable dry (1850s, 1880s, 1890s, 1930s, 1970s) and wet (1820s, 1870s, 1920s, 1940s, 1990s) decades. These patterns are strongly reflected by reservoir inflow series and by indicators of the biological status of the region’s freshwater lakes. It is argued that long-term climate indices will become increasingly important as managers seek to evaluate recent and project environmental changes within the context of long-term natural variability.     

广州市环境噪声总体水平分析及其控制：以越秀区为例

随着广州市改革开放的深入发展，作为广州市中心区的越秀区环境噪声总体水平居高不下，而且还有上升趋势。本文分析了越秀区环境噪声现状和发展，对环境噪声总体水平的控制提出建议和对策。