典型的崩岗具有“圆形露天剧场”般的沟头,发育在深厚的红色花岗岩风化壳上,通常包括集水坡面、崩壁、崩积体、沟道、洪积扇5个地貌组成部分;崩壁自上而下可分为表土层、风化红粘土层(红土层)、风化砂质红粘土层(砂土层)、风化粗碎屑层(碎屑层)。中国的崩岗与马达加斯加的lavaka属于同类地貌,两者具有地貌学上的可比性。崩岗群是劣地的表现形式之一,但与欧洲的badland有不同的侵蚀过程,也不同于意大利和巴西的两种沟谷侵蚀地貌calanchi和vocoroca。崩岗主要发育在华南和东南热带和亚热带湿润季风气候区中等偏缓的丘陵坡地上,由沟谷侵蚀发展而成,是沟谷侵蚀的高级阶段。崩岗沟道侵蚀产沙量占崩岗沟谷流域侵蚀产沙量的一半以上,其中沟道沟壁崩塌侵蚀产沙量与沟床下切侵蚀产沙量又各占崩岗沟道侵蚀产沙量的一半左右。野外人工模拟降雨试验是研究崩岗流域侵蚀、产流和产沙过程的有效手段。崩岗流域侵蚀产沙量可以通过崩岗沟谷和洪积扇地形测量加以估算。

The typical benggang has an amphitheater-like gully-head, mainly occurs in the deeply weathered granite area in southern and southeastern China. It usually consists of five parts: water-collection slope, headwall, colluvium, channel, and debris fan. From top to bottom, benggang headwall may be divided into four soil layers: topsoil, red soil, sandy soil, and clastic soil. Benggang in China and lavaka in Madagascar belong to the same type of landform with comparable geomorphologic characteristics. Benggang may be considered as one of the badland landscapes, but it has different erosion process. It is also different from the other two gully erosion landforms in Italy and Brazil: calanchi and vocoroca. Benggang is mainly distributed in moderate hilly region and subtropical maritime climate zone of southern and southeastern China. Usually benggang is also considered to develop from gully erosion, and it is treated as the advanced stage of gully evolution. The sediment yield of benggang channel erosion accounts for more than half of the sediment amount of the whole benggang gully catchment, and likewise the sediment yield of channel-bed accounts for about half of the sediment amount of the whole gully catchment. Simulated rainfall is a powerful tool to study the effects of rainfall on surface processes and erosion. The in situ artificial simulated rainfall is an effective method to study benggang erosion, slope runoff, and sediment transportation in benggang gully catchment. Benggang erosion is a geomorphic critical phenomenon. This critical phenomenon occurs only when the rainfall, topography, soil, and runoff exceed their critical thresholds. Field artificial rainfall experiments based on simulated rainfall-slope runoff-erosion process-sediment production observations may greatly improve the understanding of benggang erosion in southern and southeastern China. The sediment yield of benggang catchment may be estimated by the morphometric analyses on the topographies of benggang gully and debris fan

自黄土高原退耕还林还草政策实施以来,在水源涵养功能明显提升的同时径流显著减少,导致该区域出现了水源涵养服务与水供给服务间的权衡问题。为探究径流减少的原因,进而为不同空间尺度的生态系统服务权衡提供支撑,本文分析了陕北黄土丘陵沟壑区2006-2011年降水和植被变化对径流影响的尺度效应。结果表明：研究区域内汛期降水量呈现出由东南向西北逐渐减少的空间分异特征;在研究时段内,植被恢复效果明显,近8成地区植被覆盖状况得到了改善,尤其是植被覆盖较差的地区恢复效果更为显著;在各子流域中,降水与径流间呈现出显著的正相关性,二者的相关系数随着子流域面积的增加而增大,表现出明显的尺度效应。随着子流域面积增大,15°以上土地比例增加,陡坡植被覆盖类型趋于均一化,具有显著截流功能的林地呈现减少趋势是尺度效应形成的主要原因。NDVI与径流的相关性不显著,二者的相关系数随着子流域面积变化的规律性不强,植被对径流影响没有明显的尺度效应。

Water conservation capability of the loess plateau increased significantly since the Grain for Green project started. At the same time, the amount of runoff significantly reduced, resulting in the question of how to balance the water conservation needs and the need for water supply in the region. In order to explore causes of the runoff reduction and provide support for balancing different needs for water at different scales, the variation of precipitation and vegetation as well as the scale effect of its impact on runoff in northern Shaanxi loess hilly-gully region during 2006 to 2011 were examined. The results show that: Precipitation of flood season gradually reduced from southeast to northwest in the study area. During the research period, vegetation restored significantly, nearly 80% of vegetated area was improved, especially in areas with poor vegetation conditions. Precipitation and runoff had significant positive correlation. With the increase of sub-watershed area,the correlation of precipitation and runoff increased, which shows a clear scale effect. The main reason was that land use structure above 15° of slope changed along with the spatial scale—vegetation types at steep slope tended to be homogenous and forest that has significant water conservation function decreased along with the increase in sub-watershed area. The correlation between NDVI and runoff was neither significant nor forming a clear relationship with the area of sub-watersheds, therefore the scale effect of vegetation influence on runoff was not obvious.

Topographic feature points and lines are the framework of topography, and their spatial distance relationship is an breakthrough in the study of topographical geometry, internal structure and development level. Proximity distance (PD) is an indicator to describe the distance between the gully source point (GSP) and the watershed boundary. In the upstream catchment area, PDs can be expressed by the streamline proximity distance (SPD), as well as by the horizontal proximity distance (HPD) and the vertical proximity distance (VPD) in the horizontal and vertical dimensions, respectively. The series of indicators (e.g., SPD, HPD and VPD) are important for quantifying the geomorphological development process of a loess basin because of the headward erosion of loess gullies. In this study, the digital elevation model data with 5 m resolution and a digital topographic analysis method are used for the statistical analyses of the SPD, VPD and HPD in 50 sample areas of 6 geomorphic types in the Loess Plateau of northern Shaanxi. The spatial characteristics and the influencing factors are also analysed. Results show that: 1) Central tendencies for the HPDs and the VPDs for the whole study area and the six typical loess landforms are evident. 2) Spatial patterns of the HPDs and the VPDs exhibit evident trends and zonal distributions over the whole study area. 3) The HPDs have a strong positive correlation with gully density (GD) and hypsometric integral. The VPDs also correlates with GD to an extent. Vegetation cover, mean annual precipitation and loess thickness have stronger effects on the VPD than on the HPD.

主要探讨了在流域地貌演化的不同阶段,沟壑密度与切割深度的复杂关系,建立了沟壑密度随切割深度变化的理论极值模型及相应阶段的函数,补充了各演化阶段地貌形态要素的定量、定性描述;反之,可用沟壑密度与切割深度的关系推断流域地貌的演化阶段。

According to the geographical cycle theory, drainage landform evolution process is divied into three periods—young, mature and old period. In defferent evolution periods, the relation between gully density and cutting depth is various. However, it is sure that landforms are the most tattered and gully density reaches the maximum in the later young—early mature period. By presuming that the drainage landform is evoluted into hills in the period, the maths equation of the theoretical maximum of gully density was established, which is <i>D</i>=ctg<i>θ^h∫_h₀^max</i>d<i>h</i>/(<i>h</i>ctg<i>a</i>+c)² (1) where:<i>D</i>: gully density;<i>θ</i>: slope;<i>h</i>: cutting depth;<i>c</i>: gully bed average width;<i>h</i>₀: cutting depth minimum;<i>h</i>_max: cutting depth maximum On the above presuming base, the maths function on relation between gully density and cutting depth were established for the defferent development periods. The maths function shows that:①in the early young period, the gully density and cutting depth increase at the same time; ②in the later young—early mature preiod, gully density reaches the maximum and it decreases as cutting depth imcreases; ③ in the later mature—old preiod, gully density decreases as cutting depth decreases. Two example calculations demonstrate that the maths equation of the theoretical maximum of gully density may be used in practice. It can infer drainage landform evolution period and predict soil erosion developing tendency. It supplements quantitative anslysis on landforms shape elements with drainage landform evolution in defferent periods.

地貌的发育在特定的条件下往往呈现空间分布上由“新”至“老”的过渡,据此,对地貌类型与特征在空间上的序列采样,即可为研究某种地貌的个体发育提供基本依据。该方法即为地貌学研究中的空代时。本文首先介绍了空代时方法产生的背景与基本概念。分析了近年来空代时方法应用于河流地貌、构造地貌、河口海岸地貌等不同地貌类型演化过程的研究进展。在此基础上,明确了空代时方法在地貌学研究中的适用条件、影响因素及分类体系,并提出了地貌学空代时的研究范式。本文认为今后的研究工作一方面应充分利用海量的地理空间数据,运用空代时方法研究多种空间尺度下的地貌演化的问题;另一方面,应结合现有的物理机制和统计规律,构建集形、数、理一体化的地貌演化模型。

Geomorphic evolution often presents a spatial pattern of a "young to old" distribution under certain natural environment condition, whereby sampling the geomorphic types and characteristics in spatial sequence can provide some evidence for the evolution of the individual geomorphologic object. This so-called space-for-time substitution has been a methodology in geomorphology research. This paper firstly introduced the basic concepts and background of space-for-time substitution, then a full review has been conducted of recent research progress in geomorphic evolution based on space-for-time substitution, such as fluvial landform, structural landform, estuarine landform and coastal landform. Finally, the explicit terms like suitable conditions, influencing factors and classifications have been summarized so that the research paradigm of space-for-time substitution was proposed. We argued that in the future, the researchers should focus on a full use of massive geographic data for geomorphic evolution research at multi-spatial scales, as well as an effective combination with physical mechanisms and statistical laws for a comprehensive geomorphic evolution modelling.

地貌分类体系是地貌图研制的关键之一,本文在总结国内外地貌及分类研究的基础上,借鉴20世纪80年代的中国1∶100万地貌图制图规范,基于遥感影像、数字高程模型和计算机自动制图等技术条件,归纳总结了数字地貌分类过程中应遵循的几大原则,分析了它们之间的相互关系,讨论了数字地貌分类的各种指标:包括形态、成因、物质组成和年龄等,提出了中国陆地1∶100万数字地貌三等六级七层的数值分类方法,扩展了以多边形图斑反映形态成因类型,以点、线、面图斑共同反映形态结构类型的数字地貌数据组织方式,并详细划分了各成因类型的不同层次、不同级别的地貌类型。中国1∶100万数字地貌分类体系的研究,为遥感等多源数据的陆地地貌解析和制图提供了规范,也为《中华人民共和国地貌图集》的编制奠定了基础,同时为全国大、中比例尺地貌图的分类和编制研究提供了借鉴。

以研究区3030个流域水文数据为基础,利用数字高程模型（DEM）并运用非线性拟合法分析中小流域集水面积阈值与河源密度的相关关系,分析集水面积阈值与河源密度的幂函数关系可得,幂指数a近似为-1,拟合公式常系数k具有区域分布特征,反映了不同地区的河网发育程度,k值越大,河源密度越大,河网越密集,河网发育程度越高。对河源密度随集水面积阈值的变化趋势进行分析,发现2个具有统计意义的阈值临界点,分别为河源从坡面到沟道及从沟道到河道的集水面积分界点,在研究区内选择不同k值区间的贡曲流域、辰清河流域和藤条江流域作为样本流域,利用样本流域数字正射影像（DOM）手工提取其沟谷河网及主河道河网的图形信息和水文信息,并与分界点处阈值提取的河网作对比,将分析得出的河网密度相对误差率作为检验标准,对临界点的物理意义进行检验。

沟谷源点作为沟沿线上最为活跃的部位,其分别到上游分水线、下游沟谷线的流线空间比对关系,是表征三线空间结构的重要突破口。它在空间上向流域分水线逼近的程度,是量化黄土流域地貌系统发育程度的重要切入点。为探究黄土地貌区流域沟谷源点向流域分水线逼近的程度,揭示黄土流域地貌发育进程及该进程所表现的主要侵蚀方式,本文从水平和垂直2个维度,构建量化三线空间结构关系的核心因子——逼近度（PI）,其中包括水平逼近度（HPI）和垂直逼近度（VPI）,基于5 m分辨率数字高程模型,在陕北黄土高原遴选了包含16种地貌类型的42个样区,利用数字地形分析方法,探讨其平均值（MHPI, MVPI）的空间分异规律。另外,选择其中南北序列分别代表黄土塬、残塬、梁状丘陵沟壑和峁状丘陵沟壑区的淳化、宜君、甘泉和绥德4个地区,完备包含一至五级别沟谷的典型流域为重点实验样区,探讨陕北黄土高原流域尺度平均逼近度变异指数（MPIV）序列性特征。实验结果表明：① 陕北黄土高原平均逼近度（MPI）存在强烈的空间自相关,MHPI在南北序列上先增大后减小,东西方向上逐渐减小,在黄河沿岸峡谷丘陵区MHPI达到最大;MVPI由西南—东北先减小后增加,由西北—东南逐渐减小,在渭北黄土台塬区达到最小;② 在流域尺度上,MPIV值的正负与黄土塬区、丘陵沟壑区敏感相关;③ 4个重点样区MHPI、MVPI与其它地形因子存在南北序列上的一致性。104个外部汇流区平均水平逼近度与平均坡度相关性较好（P=0.43, aP=0.75, a

面积高程积分(Hypsometric Integral, HI) 是通过统计流域地表的高程组合信息,从而揭示流域地貌形态与发育特征的重要指标。本文以1:10000 比例尺5 m分辨率DEM数据分析流域面积高程积分计算时的影响因素,以SRTM数字高程模型数据为基本信息源,研究黄土高原重点水土流失区的面积高程积分空间分异特征。研究工作首先讨论并总结了面积高程积分的地学含义,明确了DEM分辨率以及分析面积对于面积高程积分计算的影响,并分析各地貌对象面积高程积分的相关性;然后,面向黄土高原重点水土流失区,采用面向多尺度分割的方法,基于小流域面积高程积分,实现了黄土高原重点水土流失区地貌分区。研究结果表明,DEM分辨率对于小流域面积高程积分计算影响较小,当小流域面积阈值达到10 km²时,面积高程积分趋于稳定;各地貌对象中,流域面&mdash;正地形&mdash;沟沿线、山顶点&mdash;山脊线&mdash;流域边界这两组组内面积高程积分值相关性非常强;基于面积高程积分的地貌分区,与黄土高原地区水土流失分区图和输沙模数分区图具有相当程度的耦合关系,并细化了原有分区结果。

Hypsometric integral is a terrain analysis factor with apparent physical and geomorphologic meanings which could reflect the landform erosion stage and evolution process. As a macroscopic parameter and method in terrain analysis, the applications of hypsometric integral could reveal the quantitative characteristic of landform evolution in catchment scale. In this paper, 5 m resolution DEMs and 3 arc-second resolution SRTM DEMs are used respectively to identify the impact factors of HI and its spatial variation in the Loess Plateau. Firstly, the geomorphologic meaning is discussed and summarized. The effect of DEM resolution and the analysis area in HI calculating is probed. With different DEM resolutions, the HI values derived could keep almost the same. When the area of catchment reaches 10 km², the HI tends to be stable, which is regarded as a critical area for extracting HI in this study. Then, the geomorphic feature HI is proposed and the correlation of each kind of HI is calculated. There exist two feature groups in which the correlation coefficient is rather large. They are respectively catchment HI, positive terrain HI, shoulder line HI and peak HI, ridge line HI, and catchment boundary HI. Finally, the landform division based on HI is created through multiresolution segmentation in loess area. The coupling relationships exist in this division and water & soil loss map, sediment transport value map. The division in this paper refines the original map to a certain extent.