Regional hydromorphological characterization with continuous and automated remote sensing analysis based on VHR imagery and low‐resolution LiDAR data          下载免费PDF全文

Luca Demarchi  Simone Bizzi  Hervé Piégay 《地球表面变化过程与地形》2017,42(3):531-551

Recent developments in remote sensing (RS) technologies lead the way in characterizing river morphology at regional scales and inferring potential channel responses to human pressures. In this paper, a unique regional database of continuous hydromorphological variables (HyMo DB) based on areal and topographic data has been generated from RS analysis. Key riverscape units with specific geomorphic meaning have been automatically mapped for 1700 km² of river floodplains from simultaneous very‐high‐resolution (VHR) near‐infrared aerial imagery and low‐resolution LiDAR‐derived products. A multi‐level, geographical object‐based architecture (GEOBIA) was employed to integrate both spectral and topographic information and generate a regional classifier able to automatically map heterogeneous fluvial patterns in different geographical and topographical contexts of the Piedmont Region (Italy). This HyMo‐generated DB offers a unique set of tools for hydromorphologists and can be exploited for different purposes. For the first time, topographic information can be exploited regionally per riverscape unit class, allowing for quantitative analysis of their regional spatial and statistical variability. In this manner, river types can be automatically characterized and classified using objective and repeatable hydromorphological variables. We discuss the potential of quantifying functional links between riverscape units and their driving processes, a valuable source of information to start assessing and highlighting the entity of potential channel adjustments at the regional scale to human pressures. The HyMo DB can also be integrated with historical, field‐based information to better comprehend current fluvial changes at a local scale. In view of future RS acquisitions, the present approach will result in a suitable procedure for quantitative, objective and continuous monitoring of river evolutions over large scales. This type of hydromorphological characterization will allow regional trends and patterns to be highlighted through time and river management strategies to thus be implemented at both regional and local scales. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Changes of flood risk on the northern foothills of the Tatra Mountains     

Z. W. Kundzewicz  M. Stoffel  B. Wyżga  V. Ruiz-Villanueva  T. Niedźwiedź  R. Kaczka  J. A. Ballesteros-Cánovas  I. Pińskwar  E. Łupikasza  J. Zawiejska  P. Mikuś  A. Choryński  H. Hajdukiewicz  B. Spyt  K. Janecka 《Acta Geophysica》2017,65(4):799-807

The present paper reviews selected outcomes of the FLORIST project devoted to flood risk in the region of the northern foothills of the Tatra Mountains in Poland and summarizes novel results. The project encompassed theoretical, field, and modeling work. It was focused around observation-based hydroclimatology; projections for the future; dendrogeomorphology; as well as influence of transport of large wood on fluvial processes. The project improved understanding and interpreting changes in high-flow frequency and magnitude as well as changes in flood risk in the region, related to the presence of large wood in mountain streams. A unique database on past episodes of intense precipitation and flooding was created, harnessing multiple sources. The project showed that the analysis of tree rings and wood logs can offer useful information, complementing and considerably enriching the knowledge of river floods in the region of northern foothills of the Tatra Mountains. Retrospective and scenario-defined modeling of selected past fluvial events in the region was also performed.  相似文献   

基于宽巷/窄巷法的星载GPS相位数据的模糊度解算和周跳探测   总被引：1，自引：0，他引：1  

郭金运  孙佳龙  鞠晓蕾  申秀梅 《测绘科学》2009,34(6)

星载GPS技术是卫星精密定轨及其任务顺利执行的关键,而模糊度和周跳问题是星载GPS相位数据应用的难题。本文利用宽巷/窄巷法对星载GPS相位数据进行模糊度计算和周跳探测,给出了模糊度计算和周跳探测的计算公式和解算步骤。利用宽巷/窄巷法对CHAMP卫星实际星载GPS数据进行了处理,结果表明该方法是可行的,同时由于卫星的高速运动,星载GPS数据的模糊度解算和周跳探测难度也较大。  相似文献   

多波束测深的异常数据编辑技术和实现     

阳凡林  郑作亚  郭金运  刘智敏 《测绘科学》2009,34(6)

因为海况、仪器噪声、海水中浮游生物等因素存在,测深数据中含有大量的异常数据和噪声,由于数据量大,如何有效定位异常数据和噪声是目前国际上的研究热点。本文详细介绍了手工交互式编辑和常用的几种自动编辑方法,并重点介绍了基于测点密度的图像滤波方法,阐述了多波束测深数据编辑软件的实现,对多波束测深数据的快速编辑有一定的参考意义。  相似文献   

Central configurations for the planar Newtonian four-body problem     

E. Piña  P. Lonngi 《Celestial Mechanics and Dynamical Astronomy》2010,108(1):73-93

Planar central configurations of four different masses are analyzed theoretically and computed numerically. We follow Dziobek’s approach to four-body central configurations with a straightforward implicit (in the masses and distances) method of our own in which the fundamental quantities are each the quotient of a directed area divided by the corresponding mass. We apply a new simple numerical algorithm to construct general four-body central configurations. We use this tool to obtain new properties of the symmetric and non-symmetric central configurations. The explicit continuous connection between three-body and four-body central configurations where one of the four masses approaches zero is clarified. Some cases of coorbital 1+3 problems are also considered.  相似文献   

Reference frame access under the effects of great earthquakes: a least squares collocation approach for non-secular post-seismic evolution     

D. D. Gómez  D. A. Piñón  R. Smalley  M. Bevis  S. R. Cimbaro  L. E. Lenzano  J. Barón 《Journal of Geodesy》2016,90(3):263-273

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盐酸提取-电感耦合等离子体原子发射光谱测定土壤中的有效钼     

王金云  唐永伦  黄勤  程丽娅 《安徽地质》2011,21(3):211-213

以草酸-草酸铵溶液(Tamm溶液)浸提土壤中的有效钼,过滤,滤液蒸干,马弗炉高温灰化,盐酸提取,采用电感耦合等离子体发射光谱仪测定土壤中的有效钼。方法检出限(3s)达0.012×10-6,精密度(RSD,n=12)为2.31%～4.78%,经国家土壤有效态一级标准物质的验证,结果满足分析要求。  相似文献   

地图数据几何纠正时仿射变换与相似变换的对比分析   总被引：9，自引：1，他引：9  

郭金运  朱明法  徐泮林 《测绘通报》2001,(4):23-24,27

分析了地图数字化过程及其坐标变换，利用仿射变换和相似变换对聚酯薄膜和纸质地形图与航摄数字影像进行了实验研究。结果表明，对于地图数字化坐标换算，仿射变换优于相似变换，特别是对于纸质地图，仿射变化具有明显的优越性。  相似文献   

基于多种度量的电离层TEC混沌预测分析     

孙佳龙  郭金运  郭淑艳 《地球物理学进展》2013,28(3)

利用东经120°,北纬45°上空的2008年年积日101～150 d时间段内共600个电离层格网TEC数据为时间序列样本,分析了该点上空电离层TEC参数的混沌特性,发现其关联维数为2.2632,嵌入维数为5,最大Lyapunov指数为λ=0.0833,表明该点上空电离层TEC时间序列具有混沌的特征,存在混沌现象.采用加权一阶局域法对TEC时间序列进行预测时,在有效预报尺度内,利用各种度量进行预报得到的中误差都随着预报天数的增加而逐渐增大,但预报的相对误差却是在一定幅度范围内上下波动.采用四种距离度量以及皮尔森相关系数和Jaccard相似系数进行预报,其预测结果或者平均中误差较大,或者平均相对误差较大,结果不理想.其中,采用标准化欧氏距离得到的平均中误差最大,达到5.107TECU,而采用皮尔森相关系数得到的平均中误差最小,为5.078TECU;对于平均相对误差而言,由切比雪夫距离得到的平均相对误差最大,为0.185,而Jaccard相似系数得到的平均相对误差最小,为0.166.而采用余弦相似度得到的预测结果,其平均中误差和平均相对误差都很小,分别为5.079TECU和0.167.因此,在一阶局域混沌预测时,采用余弦相似度作为衡量相空间轨迹的差异性是较为合适的.  相似文献   

γ射线暴火球的演化与余辉     

黄文耿  杨丕博  陆烨 《天文学报》2001,42(1):16-21

GRB主爆后，火球继续膨胀，根据暴后火球的动力学演化方程，考虑电子的分布随时间的变化，通过数值求解，得到光学R波段和X射线余辉与时间t的关系。计算结果与观测结果相比较，符合得很好。最后，还讨论了火球＋激波模型的不足。  相似文献