内蒙古奈曼旗水环境承载力评价

水环境评价模型指标体系的选取和权重的确定是研究水环境承载力模型的关键.选取地下水脆弱性能,水环境质量,水体污染,开采程度,污染河水对地下水的影响等5个评价指标进行综合评价,利用层次分析法作为一种定量研究方法,运用专家评分法确定了评价指标体系中的各指标权重,并进行指标体系的可靠性和有效性判断,对区内地下水环境进行综合评价及可开采潜力分析.根据取得分值分区,确定承载力评价分区图,为地下水资源的合理利用提供了依据.     

民和盆地南缘盐锅峡组的建立及其地质意义

民和盆地下白垩统地层出露广泛,在其中部有一整套以水下沉积构造和其中特有的蓝灰色标志层为主体的细碎屑岩系,与上、下地层有着极大差异,命名为“盐锅峡组”。该组地层剖面连续,出露甚好,顶底清楚,具独特的岩性、岩相特征。该组岩石地层单位的正式建立,不但便于区内地层划分与对比的需要,而且对盆内层序地层、构造演化、作用相分析都具重要作用。     

玉龙山东麓更新世冰川作用

利用１：１００００地形图和航空照片,对玉龙山东麓更新世冰川作用遗迹进行了调查和填图。据冰川与冰水沉积物的钙质胶结物和冰湖相钙板的ＥＳＲ测年结果,初步划分４次冰期,即０．７￣０．６Ｍａ ＢＰ的玉龙冰期。其中最早一次冰期为规模较大的山麓冰川,后２次冰期为规模较大的山谷冰川。     

气候变化对福建冬种小麦生产的影响

使用福建省３１个县小麦产量资料及相应各地的气象资料,通过气象产量与经膨胀处理后的气象因子进行相关分析,得知影响福建冬种小麦产量的关键气象因子是３月份的降水量和上年１１月中旬至１２月上旬的平均气温。分析了冬种小麦生长期气候资源变化及关键气象因子的年代变化,得出近年气候变化不利于福建冬种小麦的生产。最后对福建冬种小麦种植区重新进行了划分,对福建冬种小麦生产布局提出了建议。     

宁夏旅游资源及其功能分区评价研究

宁夏旅游资源体现出自然旅游资源的多样性与独特性,地文旅游资源的典型性,生物旅游资源的丰富性,历史人文资源的垄断性和珍稀性,生态旅游资源的兼备性,民俗旅游资源的突出性等七大特征。呈现出“一带、一轴、一点”的格局,可划分为八个大区。     

EXTRACTING FEATURES OF ALLUVIAL FAN AND DISCUSSING LANDFORMS EVOLUTION BASED ON HIGH-RESOLUTION TOPOGRAPHY DATA: TAKING ALLUVIAL FAN OF LAOHUSHAN ALONG HAIYUAN FAULT ZONE AS AN INSTANCE

Range-front alluvial fan deposition in arid and semiarid environments records vast amounts of climatic and tectonic information. Differentiating and characterizing alluvial fan morphology is an important part in Quaternary alluvial fan research. Traditional method such as field observations is a most important part of deciphering and mapping the alluvial fan. Large-scale automatically mapping of alluvial fan stratigraphy before traditional field observations could provide guidance for mapping alluvial fan morphology, thus improving subsequent field work efficiency. In this research, high-resolution topographic data were used to quantify relief and roughness of alluvial fan within the Laohushan. These data suggest that mean surface roughness plotted against the size of the moving window is characterized by an initial increase in surface roughness with increased window size, but it shows no longer increase as a function of windows size. These data also suggest that alluvial fans in this study site smooth out with time until a threshold is crossed where roughness increases at greater wavelength with age as a result of surface runoff and headward tributary incision into the oldest surfaces which suggests the evolution process of alluvial fan. Researchers usually differentiate alluvial morphology by mapping characteristics of fan surface in the field by describing surface clast size, rock varnish accumulation, and desert pavement development and analysis of aerial photographs or satellite imagery. Recently, the emergence of high-resolution topographic data has renewed interest in the quantitative characterization of alluvial and colluvium landforms. Surface morphology that fan surface initially tends to become smoother with increasing age due to the formation of desert pavement and the degradation of bar-and-swale topography and subsequently, landforms become more dissected due to tectonics and climatic change induced increased erosion and channelization of the surface with time is widely used to distinguish alluvial fan types. Those characteristics would reflect various kinds of morphology metrics extracted from high-resolution topographic data. In the arid and semiarid regions of northwestern China, plenty of alluvial fans are preserved completely for lack of artificial reforming, and there exists sparse surface vegetation. In the meantime, range-front alluvial fan displaced by a number of active faults formed a series of dislocated landforms with different offsets which is a major reference mark in fault activity research. In this research, six map units(Qf₆-Qf₁), youngest to oldest, were observed in the study area by mapping performed by identifying geomorphic features in the field that are spatially discernible using hill-shade and digital orthophoto map. Alluvial fan relief and roughness were computed across multiple observation scales(2m×2m to 100m×100m)based on the topographic parameters of altitude difference and standard deviation of slope, curvature and aspect. In this research, mean relief keeps increasing with increased window size while mean surface roughness is characterized by a rapid increase over wavelengths of 6~15m, representing the typical length scale of bar-and-swale topography. At longer wavelengths, surface roughness values increase by only minor amounts, suggesting the topographic saturation length is 6~15m for those fan surfaces in which saturation length of standard deviation of curvature is less than 8m. Box and whisker plot of surface roughness averaged over 8m² for each alluvial fan unit in the study area suggests that the pattern of surfaces smoothing out with age and then starting to become rougher again as age increases further beyond Qf₄ or Qf₃ unit. The younger alluvial fan is characterized by prominent bar-and-swale while the older alluvial fan is characterized by tributaries headward incision. Cumulative frequency distributions of relief and surface roughness in Figure 8 are determined in an 8m by 8m moving window for the comparison of six alluvial fan units in the northeast piedmont of Laohushan. From these distributions we know that Qf₆ and Qf₁ reflect the prominent relief which is related to bar-and-swale and tributaries headward incision respectively, while Qf₄ and Qf₃ reflect the moderate relief which is related to subdued topography. Surface roughness, in addition to facilitating the characterization of individual fan units, lends insight to alluvial landform development. We summarize an alluvial landform evolutionary scheme which evolves four stages depending on characteristics of alluvial fan morphology development and features of relief and roughness. The initial stage in this study site is defined as the active alluvial fan channels with bars of coarse cobbles and boulders and swales consisting of finer-grained pebbles and sand which could be reflected by high mean relief and mean roughness values. As time goes, bar-and-swale topography is still present, but an immature pavement, composed of finer grained clasts, has started to form. In the third stage, the bar-and-swale topography on the fan surface is subdued, yet still observable, with clasts ranging from pebbles to cobbles in size and there exists obvious headward tributary incision. Eventually, tributary channels form from erosion by surface runoff. Headward incision of these tributaries wears down the steep walls of channels that are incised through the stable, planar surface, transforming the oldest alluvial landforms into convex hillslopes, leaving only small remnants of the planar surface intact. Those evolutionary character suggests that alluvial fans in this area smooth out with time, however, relief or roughness would be translated to increase at greater wavelength with age until a threshold is crossed. This research suggests that relief and roughness calculated from high-resolution topographic data of this study site could reflect alluvial fan morphology development and provide constraint data to differentiate alluvial fan unit.     

对西藏岗巴上白垩统的新认识

在前人研究的基础上对岗巴地区上白垩统的划分做了厘定 ,进一步建立了晚白垩世的 1 2个浮游有孔虫化石带。根据岩性特征及化石带的研究 ,上白垩统被划分为赛诺曼期至土仑早期的冷青热组 ;土仑中期至三冬期的岗巴村口组和康潘期至马斯特里赫特期的宗山组。该区赛诺曼期与土仑期的界线位于冷青热组上部 ,以 H elvetoglobotruncana praehelvetica的初现为标志。     

Spatial production and spatial dialectic: Evidence from the New Urban Districts in China

Journal of Geographical Sciences - New Urban Districts (NUDs) are the important spatial carriers to promote urban expansion or transformation. Since the 1990s, they have been playing a more and...     

城乡关系研究进展及其对乡村振兴的启示

随着乡村振兴战略的实施,我国已经进入城乡关系变革及乡村发展快速转型的关键时期。科学认知国内外城乡关系理论发展和演变规律对实施乡村振兴战略、缩小城乡差距、调整城乡结构和优化城乡格局具有重要意义。本文在系统梳理国外城乡关系理论及我国乡村发展与城乡关系演进的阶段性特征的基础上,从经济、社会、生态及文化的视角阐述了我国乡村发展与城乡关系研究的相关进展,并在此基础上探讨了未来重点的研究领域和方向。乡村发展思维应由生产主义导向转向后生产主义,关注乡村多元价值,深化基于乡村多功能转型理论的乡村振兴机制、区域路径与模式研究;在科技迅速发展,新事物新因素大量涌现的新时代,应关注特色小镇、田园综合体、民宿及乡村电子商务等新兴乡村转型发展形态的形成机制;同时,基于不同地域类型的乡村振兴的机制与模式研究也应得到重视,结合国际乡村地理学前沿,深入开展发达地区乡村的混杂性研究。广泛的城乡空间重构进程对乡村地区产生剧烈的影响与挑战,对于乡村振兴视角下城乡空间重构的动力机制与模式的研究仍需持续关注;根据我国的特殊国情,创新适合我国基本国情与发展实际的乡村振兴理论与实现路径,推动城乡融合发展。     

中国城市行政地域与实体地域的空间差异及优化整合

中国的城市界定与行政区划紧密关联。根据2010年人口普查数据,系统分析不同尺度城市行政地域与城市实体地域的界定及其空间差异。主要结论：① 按照直辖市或地级市、设区的市和不设区的市、设街道的市和不设街道的市的层级,城市行政地域范围依次收缩,但是都大于城市实体地域范围。按照实体地域界定,2010年中国城市人口仅占30.18%。② 城市实体地域更能客观地反映城市位序规模的分布状态,而按照城市行政地域会导致规模或排序偏差。③ 未来在行政区划调整时,着重考虑撤县设市、增设地级市、确立乡级行政区划调整标准等,在建立城市实体地域时,可从独立市辖区、县城、特大镇等方面优化,并加强统计信息公开。