黄土高原沟谷地貌发育演化研究进展与展望     

熊礼阳  汤国安 《地球信息科学学报》2020,22(4):816-826

黄土沟谷是黄土地貌中最有活力、最具变化、最富特色的对象单元,黄土高原千沟万壑的地貌形态以及触目惊心的侵蚀状态也让区域内沟谷地貌的形成、发育及演化问题成为研究中焦点及前沿性科学问题。近年来,诸多学者采用地学测年法、特征表达法、监测模拟法力图实现对黄土沟谷发育演化进程中“过去-现代-未来”的科学认知。这些研究在相当程度上丰富了黄土沟谷发育过程的认知。本文梳理了黄土高原沟谷地貌演化相关研究的现状,并从黄土高原地貌演化、黄土沟谷发育、基于DEM的沟谷信息提取与表达等研究进行了系统的回顾、梳理与分析。此外,本文提出“黄土沟道剖面群组”概念与方法,试图从新的视角审视黄土沟谷地貌发育演化过程。沟道剖面在黄土沟谷发育演化进程中传递物质能量和累积地形动力,并通过径流节点的串联实现剖面群的连接与组合,形成独特的剖面“群组”模式;该沟道剖面群组是集黄土沟谷地貌特征与过程于一体的综合信息集成体,其三维空间结构是对黄土沟谷地貌发育演化的高度抽象与映射,并可望进一步丰富黄土高原数字地形分析理论与方法体系,为黄土高原黄土地貌成因机理与空间分异格局带来创新的认识。  相似文献   

Parallelization of the flow-path network model using a particle-set strategy     

Fangli Zhang 《International journal of geographical information science》2019,33(10):1984-2010

High-performance simulation of flow dynamics remains a major challenge in the use of physical-based, fully distributed hydrologic models. Parallel computing has been widely used to overcome efficiency limitation by partitioning a basin into sub-basins and executing calculations among multiple processors. However, existing partition-based parallelization strategies are still hampered by the dependency between inter-connected sub-basins. This study proposed a particle-set strategy to parallelize the flow-path network (FPN) model for achieving higher performance in the simulation of flow dynamics. The FPN model replaced the hydrological calculations on sub-basins with the movements of water packages along the upstream and downstream flow paths. Unlike previous partition-based task decomposition approaches, the proposed particle-set strategy decomposes the computational workload by randomly allocating runoff particles to concurrent computing processors. Simulation experiments of the flow routing process were undertaken to validate the developed particle-set FPN model. The outcomes of hourly outlet discharges were compared with field gauged records, and up to 128 computing processors were tested to explore its speedup capability in parallel computing. The experimental results showed that the proposed framework can achieve similar prediction accuracy and parallel efficiency to that of the Triangulated Irregular Network (TIN)-based Real-Time Integrated Basin Simulator (tRIBS).  相似文献   

基于 MODIS 数据的吐鲁番盆地 2001—2017 年 植被变化及水热组合影响分析          下载免费PDF全文

庞冉  王文 《干旱区地理》2020,43(5):1242-1252

中国西北干旱地区的气候变化及其对植被的影响一直备受关注。以地形特殊的吐鲁番盆 地为研究对象，利用实测气象站点数据、再分析气象格点数据以及 MODIS 卫星遥感植被指数，采用 趋势检验、线性回归、偏相关分析等方法，探究了该地区 2001—2017 年间的植被变化及其与水热组 合特征之间的关系。结果表明：（1）吐鲁番盆地降水量整体没有显著变化，但北部山区降水增长较 多，气温总体呈显著上升趋势，尤其是盆地底部中心区域增温较大。（2）全区域植被指数（NDVI）总 体呈极显著上升趋势，山区及中心区域 NDVI 增长率较大。（3）受水汽来源和日照时长的影响，吐鲁 番盆地周边山区高程 3 000 m 左右 NDVI 值最高，山区植被最好的坡向是西北坡。（4）吐鲁番盆地水 热组合复杂，水分条件是大部分地区植被生长的主要限制因素，降水与 NDVI 有较好的正相关，在 山区和荒漠区热量增加不利于植被生长，但中心区域受地下水和人类活动影响，水分的供给相对 稳定，热量增加利于植被生长。  相似文献   

一次强飑线过程极端大风的中尺度分析          下载免费PDF全文

沈杭锋  方桃妮  蓝俊倩  翟国庆  苏涛 《气象学报》2019,77(5):806-822

利用常规气象观测资料、区域自动气象站加密观测资料和GFS 0.25°×0.25°逐6 h的分析场数据以及多普勒雷达、风廓线等资料,通过背景形势场分析、物理量诊断分析和中尺度分析,对2018年3月4日发生在华东地区的强飑线天气过程进行了诊断分析。结果表明,这次过程具有发生时间(季节)早、移速快、范围广、致灾强等特点,是一次比较少见的早春(冬末)十分强烈的飑线天气过程,是在高空急流辐散区、低空西南急流轴前端、低涡南侧的暖区中发展起来的。飑线过程的地面要素变化十分剧烈,地面有强冷池,与飑线前暖空气之间构成了强的水平温度梯度,致使飑线强度更强;飑线经过时气压涌升所形成的雷暴高压、强气压梯度以及飑线的快速移动均有利于地面极端大风的出现。飑线发展过程中观测到弓形回波、超级单体等强天气系统。中高层动量下传和光滑湖面、喇叭口、狭管效应等特殊地形对于大风的增强效应比较显著,这些因素也加剧了地面极端大风的形成。   相似文献   

利用SketchUp制作三维地形景观的探讨     

袁薇 《四川测绘》2011,34(1):11-13

在对高分辨率影像进行几何纠正、影像拼接以及制作正射影像图的基础上,制作了某实验区的三维地形景观,并利用SketchUp进行地物的精细建模同时通过ArcGIS 9.3进行三维显示和三维系统的二次开发。实验结果表明：利用高分辨率影像制作的三维地形具有地形逼真、清晰度高、信息量丰富等特点;完成了ArcGIS与三维建模软件的数据交换以及所建立模型的查询功能。  相似文献   

烟台市1∶500地形数据整合方法初探          下载免费PDF全文

邹敏 《山东国土资源》2017,33(9):72-76

为从源头彻底摆脱传统测绘生产过程中图属分离、图库分离的弊端,该文以烟台市1∶500地形数据整合为例,统筹现有地图制图规范与G1S建库需求,在统一制定数据标准的基础上,基于EPS2008软件,提出了一套制图与建库一体化数据整合技术流程,较好地解决了地图与空间数据相互表达的问题,实现了制图与建库的一体化管理。该方法还大大降低了数据重复处理的劳动强度,提高了数据整合转换的准确性和合理性,减少了信息丢失。  相似文献   

DEM与地形分析的并行计算     

宋效东  刘学军  汤国安  王永君  田剑  窦万峰 《地理与地理信息科学》2012,28(4):1-7

总结了数字高程模型构建、特征提取等并行算法的研究进展,概述了不同并行算法的主要内容;探讨了DTA并行技术在海量地形数据可视化和高性能地学计算的应用,随着DEM的需求日益增大,高精度、高分辨率DEM产品及其附加服务也逐步产品化。最后,通过分析并行计算发展的关键问题,提出DTA并行技术的研究趋势及研究意义,合适的数据划分和结果融合策略、通用并行算法、容错机制和负载均衡策略的设计是今后研究的重要内容,尤其是如何在多种计算模式共同发展的背景下利用并行计算解决地学难题,从而得到更接近现实世界地理环境的模拟,并扩大数字地形分析的应用范围。  相似文献   

Comparing models of debris-flow susceptibility in the alpine environment   总被引：12，自引：3，他引：9  

Alberto Carrara  Giovanni Crosta  Paolo Frattini   《Geomorphology》2008,94(3-4):353

Debris-flows are widespread in Val di Fassa (Trento Province, Eastern Italian Alps) where they constitute one of the most dangerous gravity-induced surface processes. From a large set of environmental characteristics and a detailed inventory of debris flows, we developed five models to predict location of debris-flow source areas. The models differ in approach (statistical vs. physically-based) and type of terrain unit of reference (slope unit vs. grid cell). In the statistical models, a mix of several environmental factors classified areas with different debris-flow susceptibility; however, the factors that exert a strong discriminant power reduce to conditions of high slope-gradient, pasture or no vegetation cover, availability of detrital material, and active erosional processes. Since slope and land use are also used in the physically-based approach, all model results are largely controlled by the same leading variables.Overlaying susceptibility maps produced by the different methods (statistical vs. physically-based) for the same terrain unit of reference (grid cell) reveals a large difference, nearly 25% spatial mismatch. The spatial discrepancy exceeds 30% for susceptibility maps generated by the same method (discriminant analysis) but different terrain units (slope unit vs. grid cell). The size of the terrain unit also led to different susceptibility maps (almost 20% spatial mismatch). Maps based on different statistical tools (discriminant analysis vs. logistic regression) differed least (less than 10%). Hence, method and terrain unit proved to be equally important in mapping susceptibility.Model performance was evaluated from the percentages of terrain units that each model correctly classifies, the number of debris-flow falling within the area classified as unstable by each model, and through the metric of ROC curves. Although all techniques implemented yielded results essentially comparable; the discriminant model based on the partition of the study area into small slope units may constitute the most suitable approach to regional debris-flow assessment in the Alpine environment.  相似文献   

青海湖湖东沙地风沙沉积物的粒度特征   总被引：3，自引：1，他引：2       下载免费PDF全文

张登山  田丽慧  鲁瑞洁  唐清亮  石昊 《干旱区地理》2013,36(2):203-211

通过对青海湖湖东沙地克土沙区不同类型沙丘地表沉积物粒度特征的水平变化和0～20 cm垂直变化的分析,可知自然固定沙丘的表层沉积物以细砂为主,其他沙丘以中砂为主,粒度参数随着地形起伏有不同的变化特征;随着深度的增加,粗颗粒逐渐增多,细颗粒逐渐减少,粒度参数随着深度的增加呈波动减小的趋势。通过比较分析,可得出人工治理措施对沙地地表环境的影响较大,能促进细颗粒物质的沉积,有效减少地表的风蚀量。  相似文献   

Flow time estimation with spatially variable hillslope velocity in ungauged basins   总被引：2，自引：0，他引：2  

Salvatore Grimaldi  Andrea Petroselli  Gustavo Alonso  Fernando Nardi 《Advances in water resources》2010

The automated spatial estimation of the hillslope runoff dynamics is used as a valuable tool for the estimation of the travel time distribution (flow time), a major factor for the hydrologic prediction in ungauged basins. In fact, while the flow time function is usually obtained by rescaling the flow paths with constant channel and hillslope velocities, in this work a spatially distributed kinematic component, as a function of terrain features and in particular slope and land use, is implemented and its influence on the hydrologic response is tested by means of the Width Function Instantaneous Unit Hydrograph (WFIUH) framework. Hillslope surface flow velocities are evaluated by applying different uniform flow formulas within an automated DEM-based (terrain analysis) algorithm. A comparison test of the performances of the Manning, Darcy, Maidment and Soil Conservation Service uniform flow equations is performed for several case studies in Italy pertaining to different climatic and geomorphic conditions. Results provide new insights for a better understanding of the flow time function also introducing a more parsimonious and physically-based calibration scheme of the WFIUH.  相似文献