黄山市土地出让区位选择空间特征与影响因素研究

随着全国旅游业快速发展和城镇化进程加速推进,旅游城市土地投资和开发日益强盛。以典型旅游城市黄山市为案例,以1870宗城市出让用地为样本,采用数理统计、GIS空间分析等方法,分析其土地出让区位选择空间特征与影响因素。研究发现：① 商服、住宅、工业三类用地与用地总和的出让均属于凝聚型空间分布状态,分布均衡度均较低。② 城市东南部和区县城区是土地出让热点集中地区,城市外围地域是冷点集中地区。住宅用地热点地区主要集中于城市近郊、重要旅游区周围;工业用地热点地区主要集中于开发区、工业园区和重要交通沿线;商服用地热点区域主要集中于城市商业集聚区、大型公共设施和旅游景区周围、重要交通设施附近。③ 土地出让区位选择呈点状集聚、线状网络并存,表现为“东南部分布密度较高、西北部分布密度较低”“中心城区密集、外围区县稀疏,县城密集、一般乡镇分散”“交通指向显著、呈带状分布”布局特征。④ 土地出让区位选择涉及城镇化推动的城市内生型、自然环境优美的资源依托型、要素流动便利的交通指向型和集聚经济优势的开发区集中型四种选择模式。⑤ 土地出让区位选择是自然条件、人口经济发展水平、政策制度、城镇化建设、交通设施、旅游发展等因素综合作用的结果,也是政府、企业、居民等不同主体相互作用与博弈的结果。地形对土地出让区位选择的空间约束性和指向性显著;土地出让与人口规模、经济发展水平有较高匹配度;土地政策、城市规划对用地出让的规模和方向有重要影响;交通和旅游快速发展对于土地出让具有明显影响。     

盆地型城市建设用地扩展与空间形态演变——以福州市中心城区为例

盆地型城市建设用地扩展与空间形态演变受地形地貌制约明显,具有特殊的发展特征。基于2000年、2009年和2015年RS解译数据和GIS平台,对盆地型城市福州市2000—2015年中心城区建设用地扩展的规模和方向进行分析,并对其紧凑度和分形维数进行测算。结果表明:(1) 2000—2015年,福州中心城区建设用地扩展面积较大,主要扩展方向为城市的西北部和东南部,与城市总体规划相符;(2)研究前期建设用地紧凑度较低但总体呈上升趋势,分形维数相应下降,城市空间形态复杂,主要原因是建设用地受盆地地形与闽江穿越而过的限制;(3)研究后期建设用地增长速度减缓,紧凑度和分形维数同时下降,形态更加复杂,原因是西南方向大量破碎农村建设用地增加;(4)自然因素、社会经济发展、政策与规划的导向作用以及交通的发展是影响建设用地扩展的主要驱动因素。     

长春市公共服务设施用地演变格局与机制

公共服务设施用地是城市功能用地的主要组成部分,公共服务设施用地的集聚与扩散可以更直接地揭示城市空间结构与城市中心地的演变特征。本文以长春市中心城区为研究范围,利用城市用地现状图、地形图等数据资源,借助GIS软件,采用核密度、斑块聚合度指数等方法,分析了长春市2003-2013年公共服务设施用地演变特征与机制。研究发现：公共服务设施用地规模增速低于城市建成区的增速;公共服务设施用地演变特征的圈层差异明显;公共服务设施用地空间结构从“单一化核心+多次级中心”到“多样化核心+多次级中心”,空间格局从“大分散、小集中”到“大集中、小分散”;城市不同公共服务设施用地类型表现出不同的演变特征;城市公共服务设施用地演变机制为城市功能空间的整体提升、城市功能空间的互动耦合、土地利用的市场竞争、交通设施与网络的完善、城市规划的引导与调控、城市大事件的快速推动。     

基于区域密度函数的兰—西城市区域人口聚散研究

以兰州—西宁城市区域县级行政单元三普四普五普以及2009年人口数据为依托,运用探索性空间数据分析技术研究了兰州—西宁城市区域人口分布,发现该区域存在3个人口高密度中心。根据单中心密度函数与多中心密度函数拟合结果的比较,发现采用基于平方根负指数模型的多中心区域密度函数能够很好地阐述研究区域的人口集聚与扩散。研究发现,区域内存在两种人口集聚与扩散模式,兰州城区与西宁城区呈现出向心集聚的特征,而临夏市则为弱中心式扩散。     

黄河兰州城区段湿地现状及保护建议

调查了黄河兰州城区段湿地类型和分布,结果表明:黄河兰州城区段湿地总面积1729.68hm2。5000m2以上的河岸湿地共计47块,总面积517.17hm2,其中几乎无人为干扰的湿地105.99hm2,仅占河岸湿地面积的20.50%;人为破坏程度非常严重、湿地功能几乎完全丧失的近裸露湿地252.43hm2,占河岸湿地面积的48.81%。黄河兰州城区段湿地存在乱侵乱占、遭受污染、河岸湿地植被破坏和湿地功能日趋退化等问题,提出了湿地保护与恢复建议。     

京津冀都市圈建设用地格局与变化特征研究

基于2000、2010年京津冀都市圈30 m分辨率的地表覆盖数据,提取出建设用地数据信息,运用空间统计分析、空间自相关、土地类型转换及景观指标测算的方法,从规模变化、空间变化和景观格局变化的角度,揭示京津冀都市圈建设用地的空间格局及时空变化特征,并通过多元回归模型对影响建设用地变化的驱动因素进行分析。结果表明:2000年~2010年间,在京津冀一体化发展战略背景下,伴随产业升级与产业转移的快速发展,京津冀都市圈建设用地规模经历了快速增长,高密度区县数量及其空间集聚性均呈显著上升趋势;空间变化的非均衡性和两极分化特征明显,整体沿北京—保定—石家庄、北京—天津、唐山—天津—沧州三条轴线扩展,同时京津唐地区的组团扩展和网络扩展特征日趋明显,呈现"中心—外围—边缘"的圈层式结构;景观格局的空间分散态势有所增加,各区县建设用地紧凑度指数较低,变化程度较小,建设用地的斑块变化具有一定的粗放性和无序性。运用多元回归对建设用地变化的驱动因素进行分析发现,人口、GDP和固定资产投资是影响京津冀都市圈建设用地的主导因素,其中人口是影响两期建设用地扩展的主导因素。     

近50年黄河乌兰布和沙漠段辫状河道演变

依据水沙资料和断面资料,对黄河乌兰布和沙漠段辫状河道形态近50年演变特征及趋势进行探讨分析。结果表明：在大流量条件下（1966-1993年）,河流横向侵蚀、搬运堆积过程强烈,风沙入黄（河）量大,河道横向摆动频繁,辫状河道发育强烈。当黄河流量减小时（1993-2013年）,河流横向摆动能力减弱,黄河主河槽远离左岸乌兰布和沙漠沙丘,河流输沙能力减弱,汊道泥沙淤积导致心滩边滩相连,河流分汊数量明显减少,辫状河道萎缩,黄河乌兰布和沙漠段辫状河型有向弯曲型河道转变的趋势。     

产业承接背景下赣州城区功能用地扩展特征及驱动力分析

产业转移对承接地功能空间演进会产生重要影响,厘清承接地功能用地扩展的特征和驱动力差异,有助于深刻理解与掌握产业承接背景下其用地功能演变的基本规律。该文以赣州中心城区为研究对象,利用2003年、2010年、2016年城区土地利用现状数据,诊断工业、居住、商业用地的空间演化特征及主控驱动力。结果表明:1)主动承接沿海产业转移背景下,不同功能用地的扩展规模、速率等差异显著,工业用地增长由快转慢,居住用地持续快速增长,商业用地扩展呈加速态势。2)功能用地扩展形态演化趋势迥异,工业用地核心区不断扩大,沿交通轴带扩展形成放射型空间形态,并催生居住和商业用地的空间分异;居住用地沿产业园区扩展,呈现小集中大分散的组团式分布形态;商业用地由产业引导衍生专业市场,不断向团块集中型转变,形成点-轴式空间形态。3)政策性要素是功能用地扩展的主导因素,工业用地在政府主导下呈现显著的园区化成片开发趋势,居住和商业用地则受到较强的空间规划限制,不同功能用地扩展的区位选择因素差异显著。研究结论可为差别化调控产业承接地城市功能空间布局提供决策支持。     

1980—2020年粤港澳大湾区城镇用地空间格局类型演变及其驱动力多维探测

深入研究1978年改革开放以来粤港澳大湾区城镇用地空间格局类型,探索土地城镇化多维和交互驱动机制,对推进粤港澳大湾区建设,打造世界级城市群具有重要意义。本文基于模糊聚类,从规模、形态和分布3个维度划分和定义粤港澳大湾区城镇用地空间格局类型,利用地理探测器测度城镇用地空间格局多维变化驱动力及其交互作用。结果表明：① 粤港澳大湾区城镇用地空间格局类型包括分形/复杂大面积型、分形小面积型、复杂小面积型、简单小面积型和散布型5种类型,城镇用地规模和形状复杂性具有一定的正相关性,2010年后用地规模趋于稳定,形态的规则性和紧凑性得到优化,分布集中。② 人口、GDP、地方财政收入、固定资产投资额和路网密度等社会经济因素对城镇用地面积和形态变化影响显著,核心城市对城市群发展的牵引作用在2000年后得以显现。2010—2020年各影响因子对城镇用地面积、分布和类型变化的作用差异有所减弱,但社会经济因素对形状特征的影响力上升。③ 城镇用地面积特征变化的影响力交互作用最为多样,表现有非线性增强、协同增强、单因子减弱和非线性减弱4种类型;对形状、分布和空间格局类型变化的影响力交互作用主要表现为协同增强和非线性增强。核心城市牵引力、路网密度、河网密度与多数因子交互产生“1+1>2”的效果,反映出城市群核心区位、交通优势对城镇用地扩展的强烈推动作用。     

陇川县农村居民点分布研究

以陇川县农村居民点为研究对象,综合运用GIS分析技术揭示农村居民点空间分布特征与规模空间差异。选取自然环境与社会经济两个方面影响因素,结合景观格局指数分析,研究各因素对农村居民点数量、规模及形状等方面的影响。结果表明:陇川县农村居民点整体分布为聚集模式,空间数量分布呈现由护国乡至城子镇的"带状"和户撒阿昌族乡、勐约镇的"点状"聚集,且农村居民点规模热点与核密度呈现明显负相关的空间特征。影响因素方面,耕地、道路对农村居民点空间分布影响较大,高程、坡度、城镇用地与工矿用地对农村居民点规模差异影响较大,形状特征受坡度影响最大,而交通对其无明显影响。     

珠江在广州城区河段的演变及其对 城市生态环境的影响

珠江河道广州城区段的演变在广州城市生态环境演变,特别是在城市防洪减灾中起着至关重要的作用。本文融合珠江在广州城区河段(珠江隧道-海印桥）古代、近代、现代的地图资料、遥感资料和文献资料,选取典型断面数据,建立了各断面不同时段的岸线图谱,定量反映珠江该段河道的时空演变特征,根据近年来人类工程活动等相关研究成果,推演珠江河道的演变趋势,分析河道演变对于城市生态环境和城市防洪减灾产生的影响。结果显示：20世纪50年代以前,珠江河道以0.6~0.8m/a的速度逐步缩窄;50年代以后,随着珠江堤围系统的完善,河道平面形态总体趋于稳定,局部断面仍在缩窄,最后讨论珠江河道缩窄对城市洪涝灾害、水环境污染、生物多样性等几个方面的影响。研究成果可为城市发展及水环境保护决策提供理论和现实依据。     

长江中下游阻隔性河段作用机理

阻隔性河段能够阻隔上游河势调整向下游的传递,对稳定河势起到关键性作用。本文以长江中下游34个单一河段为研究对象,在系统总结长江中下游河道演变规律的基础上,归纳出阻隔性河段控制要素包括：单一微弯的河道平面形态、河段中上部无挑流节点;河相系数小于4;河道纵比降大于1.2?;凹岸黏粒含量高于9.5%;床沙中值粒径大于0.158 mm等。从Navier-Stokes方程出发,推导出河湾水流动力轴线弯曲半径的表达式,进而分析了各控制要素对水流动力轴线摆动及阻隔性河段形成的作用。阻隔性河段的判别条件为：不同流量级下水流动力轴线摆动力与河道边界条件约束力的比值始终小于1;阻隔性河段作用机理在于：即便上游河势发生调整,本河段的河道边界始终能约束主流摆动幅度,归顺上游不同河势条件下的主流平面位置,为下游河道提供了相对稳定的入流条件,从而阻隔上游河势调整向下游传递。     

Geomorphic context of channel locational probabilities along the Lower Mississippi River, USA

Channel change is an important aspect of geomorphological evolution and habitat dynamics in large alluvial rivers. Planimetric maps of channel locations were used to investigate spatio-temporal alluvial channel changes in a geomorphic context along the Lower Mississippi River (LMR). Analyses were conducted with the aid of a time-weighted locational probability map. The locational probability map was constructed in ArcGIS and covered a period of 205 years. An examination of the pixel data from the probability maps indicates a high occurrence of low probability pixels along the Lower Mississippi River, which is in accordance with the dynamism of alluvial rivers. The northern section of the Lower Mississippi River (Columbus, KY to Memphis, TN) has been much more stable than the southern river segments (Helena, AR to Natchez, MS). Areas of high channel probability (channel stability) were often associated with alluvial channel confinement from a combination of flood-plain deposits, geologic structures and large stable islands. Low channel probability locations were found along sections exhibiting the following geomorphic characteristics: changes in meander amplitude, meander neck and chute cutoffs, meander extensional processes and islands lost in channel migrational processes. The results provide a strong foundation for understanding channel change on the Lower Mississippi River and serves as a valuable instrument for future management and restoration schemes.     

Testing links between river patterns and in-channel characteristics using MRPP and ANOVA

This study tests the assumption that the characteristics of channels within multiple channel rivers are different from those of single channel rivers. Some river restoration approaches propose radical transformation of river patterns, from multiple to single channels, based on the link between river patterns and their in-channel characteristics. Determining the links between river patterns and their in-channel characteristics is complicated by differences in geology, history, climate and discharge among rivers. Furthermore, multiple channel rivers are composed of a mosaic of channel types with a range of in-channel characteristics. This study minimizes these problems by analysing a single river containing neighbouring single and multiple channel patterns with little change in discharge downstream, and by analysing all channel types. The study addressed two objectives: to determine the hydraulic geometry, energy, and sediment mobility characteristics of neighbouring single and multiple channel river patterns, and to test for statistical differences in these characteristics between patterns. The Renous River shows a wandering pattern for 11.5 km, with multiple channels around semipermanent islands and abandoned channels in the flood plain. The river displays a single channel river pattern where channels are confined by their valley walls, upstream and downstream of wandering. The analysis was conducted at three scales. First, the confined single channel and wandering multiple channel patterns were compared (pattern scale). Second, the confined channel pattern was compared to single and multiple channel sections within the wandering pattern (section scale). Third, all channel types were compared (channel type scale). Multi response permutation procedure (MRPP) and analysis of variance (ANOVA) were used to analyze differences between channels. Difference tests found no simple discrimination between the single and multiple channel river patterns of the Renous River. Tests between the single confined and multiple wandering channel patterns found few differences in the in-channel variables. The tests did find differences between multiple channel sections within the wandering pattern and confined single channels; however, a greater number of differences were found between multiple channel and single channel sections within the wandering pattern, highlighting the variability within the wandering pattern. Two groups emerged when all channel types were tested for differences: perennial main-channels containing the thalweg, and ephemeral side-channels. Therefore, side-channels define the in-channel characteristics of wandering rivers because few differences were found among main-channels in either pattern. This analysis suggests that all channel types, not just main-channels, should be investigated to obtain a complete picture of a river pattern prior to any restoration efforts. Engineers must exercise caution when applying the link between river patterns and in-channel characteristics to river restoration efforts.     

CHANGES OF RIVER BED PATTERN OF A LOWLAND RIVER: EFFECT OF NATURAL PROCESSES OR ANTHROPOGENIC INTERVENTION?

GPR and aerial surveys were conducted to study changes of channel pattern in the lower course of the Obra River (western Poland). The river is an example of an intensive anthropogenic transformation, however, the origin of the river pattern changes in its lower course is not obvious. The GPR measurements were done using a georadar MALÅ ProEx equipped with a shielded 250 MHz antenna. A 3D analysis of the GPR data supported with lithologic information indicated traces of a multi‐channel pattern. A variable orientation of sediment layering within channel bars and differences in channels depth and width pointed to changes of direction of the river bed migration. Analysis of aerial photographs and a satellite image indicated that only a few of the channels inferred from GPR could be discerned. The reason could be the more than 1 m thick fine sands layer covering all the alluvial structures. Analysis of historical maps from the eighteenth and the nineteenth centuries showed that 250 years ago the Obra was a meandering river. The maps illustrate also several meander cutoffs and decreased wetlands surface. The following transformations of the river bed pattern were discerned: 1. From braided to meandering channel pattern which could be a natural process caused by climatic and sediment transport rate changes that was also observed in case of other lowland rivers. 2. From meandering to sinuous pattern with channel islands and then to sinuous with oxbow lakes. However, further research is needed to study reasons and timing of the observed changes.     

分汊型河床的形成与演变——以长江中下游为例

本文根据多年的地质、地貌,来水来沙等考察资料,河道变迁的历史记载以及实验研究成果,分析了分汊型河床的两个必要条件及三方面的演变特征,最后用河流力图使自己的能量损耗率达于最小的假说对汊河的形成和演变作了解释。     

基于RS和GIS的城市化进程中河道时空演变分析——以深圳市布吉河为例

为研究城市化对城市河道的影响,论文选择处于粤港澳大湾区的典型高度城市化流域布吉河流域为研究区,基于1988-2015年10期Landsat系列遥感影像、2003-2017年9期Google Earth高分辨率遥感影像、2019年深圳市水系图以及1980年以来的河道整治相关文献,应用RS和GIS技术,构建城市河道演变特征...     

泥石流输沙及其对山区河道的影响

泥石流能在很短时间内将大量大小混杂的固体物质输入主河,影响主河河床演变,形成灾害。在连续观测资料的基础上,对泥石流输沙的强度、级配和时空分布特征进行了分析。通过实际测量,分析了泥石流在沟道内冲淤特征以及影响泥石流冲淤特征的因素,如泥石流活动规模和局部沟道条件等。通过水槽实验,分析了泥石流与主河交汇的机理,将泥石流入汇主河的模式概括为掺混模式、潜入模式、推进模式和堵河模式,并且从能量角度阐释了汇流区的水沙交汇特征,提出了泥石流堵江的判据。最后,分析了泥石流多发区受泥石流入汇影响,主河河床在平面形态、横断面形态、纵断面形态和河型等方面的变化特征。     

水利工程对长江荆南三口水系结构变化的影响

利用1954、1975、1990、2008和2016年5期长江荆南三口水系图进行解译,并运用灰色关联度模型定量评价区内外水利工程对水系结构变化的影响。结果表明：① 近60 多年来,荆南三口在水系结构一般特征上,河流数量由264条缩减为132条,河流长度由2 183.6 km缩短为1 560.6 km,河频率与水面率分别由0.084条/km ²、17.45%减小为0.042条/km ²、14.33%;在水系结构发育特征上,河网密度、面积长度比和河网发育系数由1954年的0.687 km/km ²、3.96 km/km ²、6.902,依次减小为2016年的0.475 km/km ²、3.17 km/km ²、4.165;从分形特征上看,三口水系4个河区的分维数都在1.5~2.0之间波动,但均呈下降趋势。这表明随着水利工程的不断建设,荆南三口水系自然发育过程受到严重干扰;② 水系结构特征变化受水库总库容影响最大,内部水利工程次之,外部水利工程影响最小,各项指标的灰色关联度均大于0.5。其中,区外水利工程与河频率、水面率、河网密度、河网发育系数、分形维数的灰色关联度分别为0.571 8、0.592 2、0.585 8、0.577 1、0.634 0;区内水利工程数量与各项指标的灰色关联度分别为0.632 5、0.652 7、0.646 5、0.630 6、0.693 7;水库总库容与各项指标的灰色关联度依次为0.707 0、0.729 4、0.722 6、0.712 7和0.728 4。③ 水利工程对水系结构的影响在不同时段呈现出不同的状态,在不同时期水利工程相继运行的叠加影响下,水系受到水利工程影响逐渐增大,水系结构逐步呈现简化趋势。     

Fluvial processes of the downstream reaches of the reservoirs in the Lower Yellow River

Evolution of the river channel downstream of reservoirs is a complex process that is closely related to the operational mode of the reservoirs and the channel boundary conditions. Numerous studies have been carried out on the fluvial processes of downstream reservoirs. However, only a few of them have focused on the relationship between runoff-sediment conditions and channel pattern indicators. Also, the impacts of river training works on fluvial processes are seldom dealt with. In this paper, the evolutionary processes of three sections in the Lower Yellow River, including Tiexie-Yiluo River mouth reach, Huayuankou-Heigangkou reach and Jiahetan-Gaocun reach, were analyzed for variations in the channel boundary line and the mainstream between 1960 and 2015. Channel pattern indicators such as sinuosity, mainstream wandering range and width/depth ratio were analyzed based on field measurements obtained by the Hydrological Department of the Yellow River Conservancy Commission. The effects of river training works on the channel evolution are then described. Since 1960, numerous medium- and large-sized reservoirs have been built on the Yellow River, including Longyangxia Reservoir, Liujiaxia Reservoir and Xiaolangdi Reservoir. These reservoirs impound the runoff from upstream and retain the sediment, which changes the runoff and sediment conditions in the downstream reach. As a consequence, annual runoff and the frequency and peak of flooding have all decreased. As a result, the flow dynamics and their action on the river channel are also reduced, which changes the dynamic state of the river course. The discrimination results obtained using the single parameter discrimination rule and the discrimination equation show that the degree of wandering is weakened in the reaches studied. The variations in the channel pattern indicators show that the sinuosity increases and the wandering range decreases with a reduction in the total annual volume of water. However, the degree of wandering has little relationship to the sediment concentration. In addition, river training works play an important role in controlling the river course. Due to improvements in the river training works, the river course has become more stable under the same runoff and sediment conditions. A new discrimination rule that takes into account the impacts of the river training works is proposed. The discrimination results were found to fit well with the actual river pattern, which shows that the discrimination rule is applicable to the Lower Yellow River. The results show that the runoff and sediment conditions are the most important factors in the evolution of the river course. The river training works have at the same time limited the wandering range of the mainstream and played an important role in the fluvial processes. Both factors combined lead to the stabilization of the river.