Relationship Between Watershed Landscape Pattern Change and Runoff-Sediment in Wind-Water Erosion Crisscross Region

This paper selected the typical wind-water erosion crisscross region Xiliugou watershed for research to reveal the impact of the landscape pattern change of the underlying surface in wind-water erosion crisscross region where soil erosion is most serious on rainfall and runoff as well as erosion and sediment.Based on the Landsat TM image data and measured data of runoff-sediment in that watershed,the paper analyzed the characteristics of watershed landscape pattern change and runoff-sediment and explored the relationship between landscape index and runoff-sediment yield by means of GIS and Fragstats.The results were included as follows.(1)Grassland was the dominant landscape.In terms of the number of patches and area change rate,from 1985 to 2010,cultivated land,forest land and construction land were most stable,followed by unused land.Unused land,grassland and cultivated land experienced the most dramatic conversion and maximally affected by human activities.(2)The inter-annual difference between annual runoff and annual sediment load was significant.Compared with the annual sediment load,the trend of decreasing runoff was more obvious.The correlation coefficient of runoff-sediment was 0.67,representing a significant correlation.(3)There was a significant correlation between the landscape index and runoff-sediment.The runoff was negatively correlated with the largest patch index,patch cohesion index,aggregation index and contagion index,but positively correlated with landscape morphology index and landscape division index.And the sediment was negatively correlated with the contagion index,aggregation index and plaque cohesion index,but positively correlated with other landscape indexes.The results indicate that with the increase of the largest patch index,patch cohesion index and aggregation index,the rainfall infiltration capacity increase obviously and the soil erosion reduce significantly.Therefore,increasing the largest patch index,patch cohesion and aggregation index of the watershed landscape can enhance the function of water storage and soil conservation as well as ecological optimization in the windwater erosion crisscross region.The results can provide theoretical support for the ecological environment construction and comprehensive utilization of water and soil resources.

A review of the research on complex erosion by wind and water

Complex erosion by wind and water, which is also called aeolian-fluvial interactions, is an important erosion process and landscape in arid and semiarid regions. The effectiveness of links between wind and water process, spatial environmental transitions and temporal environmental change are the three main driving forces determining the geomorphologic significance of aeolian-fluvial interactions. As a complex interrelating and intercoupling system, complex erosion by wind and water has spatial- temporal variation features. The process of complex erosion by wind and water can be divided into palaeoenvironmental process and contemporary process. Early work in drylands has often been attributed to one of two schools advocating either an ＇aeolianist＇ or a ＇fluvialist＇ perspective, so it was not until the 1930s that the research on complex erosion by wind and water had been conducted. There are two obstacles restricting the research of complex erosion by wind and water. Firstly, how to transform in different temporal and spatial scales is still unsettled; and secondly, the research methodology is still immature. In the future, the mechanism and control of erosion, the complex soil erodibility in wind and water erosion will be the focus of research on complex erosion by wind and water.

Spatial Scale Effects of Water Erosion Dynamics:Complexities, Variabilities, and Uncertainties

Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evaluation and hazard control in the real world. Analyzing the related scale issues is thus urgent for a better understanding of erosion variations as well as reducing such erosion. In this review article, water erosion dynamics across three spatial scales including plot, watershed, and regional scales were selected and discussed. For the study purposes and objectives, the advantages and disadvantages of these scales all demonstrate clear spatial-scale dependence. Plot scale studies are primarily focused on abundant data collection and mechanism discrimination of erosion generation, while watershed scale studies provide valuable information for watershed management and hazard control as well as the development of quantitatively distributed models. Regional studies concentrate more on large-scale erosion assessment, and serve policymakers and stakeholders in achieving the basis for regulatory policy for comprehensive land uses. The results of this study show that the driving forces and mechanisms of water erosion variations among the scales are quite different. As a result, several major aspects contributing to variations in water erosion across the scales are stressed: differences in the methodologies across various scales, different sink-source roles on water erosion processes, and diverse climatic zones and morphological regions. This variability becomes more complex in the context of accelerated global change. The changing climatic factors and earth surface features are considered the fourth key reason responsible for the increased variability of water erosion across spatial scales.

An experimental study on the influences of water erosion on wind erosion in arid and semi-arid regions

Complex erosion by wind and water causes serious harm in arid and semi-arid regions. The interaction mechanisms between water erosion and wind erosion is the key to further our understanding of the complex erosion. Therefore, in-depth understandings of the influences of water erosion on wind erosion is needed. This research used a wind tunnel and two rainfall simulators to investigate the influences of water erosion on succeeding wind erosion. The wind erosion measurements before and after water erosion were run on semi-fixed aeolian sandy soil configured with three slopes(5°, 10° and 15°), six wind speeds(0, 9, 11, 13, 15 and 20 m/s), and five rainfall intensities(0, 30, 45, 60 and 75 mm/h). Results showed that water erosion generally restrained the succeeding wind erosion. At a same slope, the restraining effects decreased as rainfall intensity increased, which decreased from 70.63% to 50.20% with rainfall intensity increased from 30 to 75 mm/h. Rills shaped by water erosion could weaken the restraining effects at wind speed exceeding 15 m/s mainly by cutting through the fine grain layer, exposing the sand layer prone to wind erosion to airflow. In addition, the restraining effects varied greatly among different soil types. The restraining effects of rainfall on the succeeding wind erosion depend on the formation of a coarsening layer with a crust and a compact fine grain layer after rainfall. The findings can deepen the understanding of the complex erosion and provide scientific basis for regional soil and water conservation in arid and semi-arid regions.

An experimental study on the influences of wind erosion on water erosion

In semi-arid regions, complex erosion resulted from a combination of wind and water actions has led to a massive soil loss and a comprehensive understanding of its mechanism is the first step toward prevention of the erosion. However, the mutual influences between wind erosion and water erosion have not been fully understood. This research used a wind tunnel and two rainfall simulators and simulated two rounds of alternations between wind erosion and water erosion（i.e., 1^（st） wind erosion–1^（st） water erosion and 2^（nd） wind erosion–2^（nd） water erosion） on three slopes（5°, 10°, and 15°） with six wind speeds（0, 9, 11, 13, 15, and 20 m/s） and five rainfall intensities（0, 30, 45, 60, and 75 mm/h）. The objective was to analyze the influences of wind erosion on succeeding water erosion. Results showed that the effects of wind erosion on water erosion were not the same in the two rounds of tests. In the 1^（st） round of tests, wind erosion first restrained and then intensified water erosion mostly because the blocking effect of wind-sculpted micro-topography on surface flow was weakened with the increase in slope. In the 2^（nd） round of tests, wind erosion intensified water erosion on beds with no rills at gentle slopes and low rainfall intensities or with large-size rills at steep slopes and high rainfall intensities. Wind erosion restrained water erosion on beds with small rills at moderate slopes and moderate rainfall intensities. The effects were mainly related to the fine grain layer, rills and slope of the original bed in the 2^（nd） round of tests. The findings can deepen our understanding of complex erosion resulted from a combination of wind and water actions and provide scientific references to regional soil and water conservation.

The wind-water two-phase erosion and sediment-producing processes in the middle Yellow River basin, China

Based on data from the middle Yellow River basin, a wind-water two-phase mechanism for erosion and sediment-producing processes has been found. By using this mechanism, the extremely strong erosion and sediment yield in the study area can be better explained. The operation of wind and water forces is different in different seasons within a year. During winter and spring, strong wind blows large quantities of eolian sand to gullies and river channels, which are temporally stored there. During the next summer, rainstorms cause runoff that contains much fine loessic material and acts as a powerful force to carry the previously prepared coarse material. As a result, hyperconcentrated flows occur, resulting in high-intensity erosion and sediment yield.

Spatial distribution of surface rock fragment on hillslopes in a small catchment in wind-water erosion crisscross region of the Loess Plateau

The cover and size distributions of surface rock fragment in hillslopes were investigated by using digital photographing and treating technique in a small catchment in wind-water erosion crisscross region of the Loess Plateau. The results indicated that the maximal cover of rock fragment was pre-sented at mid-position in steep hillslope. Rock fragment presented a general decreasing-trend along the hillslope in gentle hillslope. Rock fragment cover was positively related to gradient, rock fragment size decreased generally along the hillslope, and the size reduced with the gradient. The mean size of rock fragment was at a range of 6―20 mm in the steep hillslope, rock fragment size > 50 mm was rarely presented. The covers of rock fragment at different positions were markedly related to the quantities of rock fragment < 40 mm. The area of rock fragment of 2―50 mm accounted for 60% or more of the total area, dominating the distribution of rock fragment in the hillslopes.

Topographic Map Analysis of Laramie Range Bedrock-Walled Canyon Complex and the Goshen Hole Escarpment-Surrounded Basin, Albany and Platte Counties, Southeast Wyoming, USA

The Laramie River after flowing in a north direction through southeast Wyoming’s Laramie Basin abruptly turns in an east direction to flow across the north-to-south oriented Laramie Range in a bedrock-walled canyon and eventually reaches the lower elevation Great Plains and southeast-oriented North Platte River. The North Laramie River, Bluegrass Creek, and North Sybille/Sybille Creek also flow from the Laramie Basin in separate bedrock-walled valleys into the Laramie Range before eventually joining the Laramie River. Bedrock-walled through valleys link the various Laramie Range stream and river crossing valleys and detailed topographic maps were used to determine how this anastomosing bedrock-walled canyon complex and the large escarpment-surrounded Goshen Hole basin (located just to the east of the anastomosing canyon complex) originated. Map evidence shows multiple streams of water must have diverged in the Laramie Basin from the north-oriented Laramie River to enter the Laramie Range before converging in or east of the Laramie Range and also shows how present day through valleys enabled diverging and converging streams of water to cross the Laramie Range. The anastomosing bedrock-walled valley complex studied here extends from north of the North Laramie River valley to south of the North Sybille/Sybille Creek valley. Large volumes of water flowing from the Laramie Basin to the Great Plains are interpreted to have eroded the anastomosing canyon complex and the “downstream” Goshen Hole escarpment-surrounded basin. Headward erosion of the north-oriented Sybille and Chugwater Creek valleys across large sheets of east-oriented water are interpreted to have left the Goshen Hole escarpment-surrounded basin as a large abandoned headcut. A water source was not determined, although a continental ice sheet that deeply eroded and warped the North American continent is considered to be a possible source.

仿生中性络合剂对花岗岩摩擦磨损行为的影响研究

基于自然界生物侵蚀的络合机制,分别以柠檬酸、酒石酸和草酸等3种低分子量有机酸为有效成分配置了3种仿生中性络合剂,同浓度盐酸溶液作为对照试剂,采用往复滑动摩擦磨损试验,以H13钢球为摩擦对偶,考察仿生中性络合剂处理前后花岗岩表面的摩擦磨损行为.结果表明,3种仿生中性络合剂侵蚀处理均能诱发花岗岩表面裂隙扩张,形成溶蚀坑,岩石表面力学性能下降,矿物颗粒间联结变弱,表面摩擦磨损加剧,磨损机制以磨粒磨损为主.相比无机强酸对岩石矿物颗粒的酸蚀作用,有机酸的络合作用对花岗岩表面摩擦磨损行为的影响更为显著,其中,分子量小且结构简单的草酸相比柠檬酸和酒石酸更容易诱发花岗岩表面矿物颗粒络合溶蚀,从而促进岩石表面摩擦去除.

半夏调中颗粒治疗寒热错杂型非糜烂性反流病的临床疗效观察

目的 观察半夏调中颗粒在寒热错杂型非糜烂性反流病(non-erosive reflux disease, NERD)治疗中的临床疗效及其对高分辨率食管测压相关指标的改善情况。方法 选取2021年1月至2022年5月在武汉市中西医结合医院就诊的寒热错杂型NERD患者80例,随机分为治疗组(半夏调中颗粒)及对照组(奥美拉唑联合伊托必利),治疗4周后,比较两组患者治疗前后中医症状积分、临床疗效及高分辨率食管测压相关数据[包括食管下括约肌长度(lower esophageal sphincter length, LESL)、下食管括约肌静息压(lower esophageal sphincter pressure, LESP)、上食管括约肌静息压(upper esophageal sphincter pressure, UESP)、远端收缩延迟时间(distal latency, DL)、收缩前沿速度(contractile front velocity, CFV)和远端收缩积分(distal contractile integral, DCI)]的变化差异。结果 治疗后,治疗组中主症胸骨后烧灼、反酸和次症食欲不振、神疲乏力、手足不温的中医症状积分较治疗前降低(P<0.05),对照组中主症反酸、次症食欲不振的中医症状积分较治疗前降低(P<0.05),但两组各项中医症状积分比较差异无统计学意义(P>0.05)。治疗组的总有效率与对照组比较,差异无统计学意义(P>0.05)。治疗组治疗后高分辨率食管测压指标LESP、DCI、CFV较治疗前升高,差异有统计学意义(P<0.05);对照组治疗后LESP、DCI较治疗前升高,差异有统计学意义(P<0.05);两组治疗前组间比较差异无统计学意义(P>0.05),治疗后组间比较显示,治疗组的CFV较对照组明显升高,差异有统计学意义(P<0.05)。结论 半夏调中颗粒在寒热错杂型NERD治疗中可有效改善患者的临床症状,同时调节食管体部运动功能,且安全性高,无明显不良反应。

新疆复杂侵蚀环境下长距离输水管道阴极保护技术实践与展望

近年来新疆长距离输水管道工程建设迅速,钢管(SP管)、预应力钢筒混凝土管(PCCP管)应用较为广泛。由于新疆地貌单元多、地质条件复杂,工程建设普遍面临高地震、严寒、侵蚀性土壤环境的考验,管道设计除了考虑大流量、高工压因素外,还需要重点研究水、土壤等侵蚀介质对管道造成的破坏。介绍了土壤腐蚀的机制及阴极保护方法,着重介绍了阴极保护工程领域相关进展情况,对阴极保护的必要性及技术应用进行了概述。结合若干工程输水管线实例对阴极保护技术发展进行了总结,提出阴极保护技术发展的关键技术和今后需要进一步关注的重点。

Simulation Study on the Dynamic Processes of Natural-Social Complex System of Soil Wind Erosion

The studies of soil wind erosion in China were concentrated on field deflation observation and qualitative analysis of wind erosion factors in the 1970s.In the subsequent decade,a series of simulation studies were conducted in wind tunnel to explore the physical mechanism of soil wind erosion.In the meanwhile,the effects

孟加拉湾缅甸若开盆地上新统斜坡水道复合体沉积特征

斜坡水道复合体是孟加拉湾缅甸海上若开盆地上新统最重要深水沉积结构单元之一。研究工作以地震响应与深水储层之间的对应关系为指导,二、三维地震资料中的强振幅属性用以判断水道复合体内的粗粒沉积。利用多种地震技术,包括相干切片分析、地质异常体处理以及三维可视化,将斜坡水道复合体从背景中区分出来,并从斜坡水道复合体的外部几何形态、内部充填特征以及储层性质等方面进行了详细描述。研究区上新统内刻画出几期规模较大的加积型水道砂,沿着水流方向,水道砂在7～16 km范围内变化,宽度不超过10 km,垂向上由3～5个单砂层组成,单砂层之间彼此连通。加积斜坡水道复合体有望成为若开盆地最有利的勘探目标。

北方农牧交错带风水蚀复合区水土流失现状与综合治理对策

风水蚀复合区是中国北方农牧交错带的一部分。区域的东面与南面毗邻水蚀地貌形态,东南界为沙漠化土地发生、发展的东南界;区域的西面与北面与风蚀地貌形态接壤,西北界为旱作农业的西北界。复合区包括74个县(旗),面积42.77万km2,总人口2400万(2004年)。主要生态问题为:沙漠化持续发展,沙尘暴频发;土地退化严重,承载力急剧下降;生态环境恶化,自然灾害频繁。复合区水土流失的主要特点表现为风水蚀在时间上交错,空间上叠加。受侵蚀营力系统与环境系统的制约,水土流失类型表现出明显的地域分异规律。2000年水土流失面积26万1517.35 km2,占全区土地面积的61.14%;复合区每年流失土壤11.97亿t,其中水力侵蚀量5.55亿t,风力侵蚀量6.42亿t。近20多年来,复合区大部分地区的水土流失面积有所减少,侵蚀强度有所降低。随着国家加大生态建设的力度,预计在未来的十到几十年,复合区的水土流失态势将呈现逐步逆转的趋势,但局部的水土流失状况依然很严峻。风水蚀复合区水土流失治理要以预防为主、保护领先为原则,生物措施、农业技术与工程措施相结合综合治理,把国家的生态需求与农户的经济需求相结合,依法协调经济开发与环境保护的关系,注重科学研究,提高科技含量。根据风水蚀复合区现状,提出了一些治理工程项目,主要包括复合区黄河粗泥沙综合治理工程和生态修复工程。这些工程的实施,将大大减少进入黄河的粗泥沙量,风水蚀复合区水土流失状况可以得到改善。

砒砂岩区典型小流域复合侵蚀动力特征分析

以鄂尔多斯高原砒砂岩区水力、风力、冻融交错侵蚀作用为研究对象,选择准格尔旗二老虎沟小流域作为研究流域,对侵蚀环境参数进行定位观测,统计分析水力、风力、冻融作用的年内变化过程。采用数据标准化后的层次分析法,揭示水力-风力-冻融交错作用过程,辨识高侵蚀风险发生的时阈及动力交错模式。研究表明:砒砂岩区复合侵蚀作用可分为风冻交错、风水交错和风水冻交错三个典型动力组合模式,风水交错侵蚀是该地区的主要侵蚀模式;砒砂岩区年内存在三个高侵蚀风险期,即风-冻融交错侵蚀期(2月上旬至3月中下旬),风-水交错侵蚀期(6月中上旬至8月中下旬),水-风-冻融交错侵蚀期(10月中旬至11月中下旬)。

模拟降雨条件下覆沙坡面产流产沙过程研究

【目的】分析不同覆沙条件下坡面降雨的产流产沙过程,为揭示黄土高原水蚀风蚀交错区风水复合侵蚀机制奠定基础。【方法】采用3个雨强（0.5,1.0,1.5mm/min）和3种覆沙方式（全坡、半坡、无覆沙）在室内进行模拟降雨试验,分析不同雨强和覆沙条件下坡面的产流产沙特征。【结果】坡面覆沙与无沙坡面（裸坡）相比延长了降雨初始产流时间1~30min;坡面覆沙后使得坡面的产流产沙过程复杂化,出现多峰多谷现象;坡面的累计径流量和累计产沙量均与降雨历时呈显著线性相关,相关系数在0.9以上;累计径流量与累计产沙量之间呈函数相关性,相关系数在0.90以上。【结论】坡面覆沙在一定程度上加剧了侵蚀的发生。

风水复合侵蚀研究述评

风水复合侵蚀或风水交互作用是干旱、半干旱地区常见的侵蚀过程。这种风力与流水对同一侵蚀对象(区域)的共同作用或交替作用塑造了风蚀水蚀交错区特有的侵蚀地貌景观。作为一个相互联系、影响的复杂系统,风水复合侵蚀具有明显的时空分布特征,其侵蚀过程可以划分为古代过程与现代过程。由于以往的风蚀和水蚀研究相互独立,风水复合侵蚀的研究起步较晚。在研究中存在着尺度转化与研究方法不成熟等问题。对风水复合侵蚀的机理与防治以及土壤复合可蚀性的研究都将成为今后研究中的重点与难点。

基于复杂网络模型的黄土模拟流域坡面形态演化

坡面形态演化是坡面系统过程作用的体现,是流域地貌系统研究重要内容之一。该文运用复杂网络方法构建坡面形态空间演化结构,探讨坡面系统演变规律。采用近景摄影测量方法得到模拟黄土坡面的9期地形数据,运用面向对象分割方法,得到了7种坡形类型空间分布图。以坡形为节点,边为坡形之间的空间连接关系,构建坡面空间网络图。研究结果得到坡面网络模型属于无标度网络,具有异配网络特征,其中陡坡是坡面网络的关键节点,控制着网络空间结构。网络演化中双直形坡的平均度下降显著,陡坡节点发育影响着系统输沙量。网络结构熵开始急剧增大,经历平缓增大到稳定状态,依据网络结构熵的变化将网络演化分为发育期、发展期和成熟期3个阶段。降雨强度增大使得坡面网络的结构熵变化显著,加剧了坡面系统演化。研究表明复杂网络框架是研究地貌系统演化一种有效途径。

东柳沟沉积泥沙粒径空间分布与特征

选取东柳沟流域作为研究区域,通过分析主河道中泥沙颗粒的粒径特征,研究流域沉积物的分布规律及其粒径变化过程。应用激光粒度仪对研究区内的河道沉积土样进行测定,使用秩和检验对泥沙颗粒特征进行分析,得到流域沉积泥沙粒径分布及变化规律。结果表明,根据中值粒径和河道比降的变化,将东柳沟流域分为丘陵区、沙丘区和农田区3个区域。流域沉积泥沙的中值粒径从上游丘陵区到下游农田区逐渐呈减少的趋势。3个分区的沉积泥沙级配特征有显著不同,丘陵区的沉积泥沙主要由粗沙构成,极粗沙和中粗沙约占57%。而沙丘区和农田区以细沙为主,且越往下游细沙含量越大,其中沙丘区沉积物中细沙及更细的颗粒所占比例约为64%,农田区沉积物中细沙及更细的颗粒所占比例约为84%。据此表明,东柳沟的侵蚀过程在空间上表现为水力侵蚀和风力侵蚀作用的交替叠加,其中沉积泥沙中值粒径变化最剧烈的地方是风蚀和水蚀交错最为频繁的区域。

基于膨胀和腐蚀的迭代优化算法

有效地优化膨胀和腐蚀操作是目前数学形态学领域中广泛研究但尚未彻底解决的问题之一.提出一种优化的膨胀和腐蚀算法,对于任意简单连接的结构元素,通过引入4个概念定义其边界,并且提出一个辅助算法检测这4种边界.在此基础上,得到3个迭代公式,将膨胀和腐蚀重定义为迭代计算,改进后的优化算法时间复杂度为O(n3).此外,因为不用进行结构元素的分解,优化算法适合在线应用.仿真结果表明,在相同参数情况下,新算法的性能优于Yang等提出的算法.