scholarly journals Simple Model for Simulating Characteristics of River Flow Velocity in Large Scale

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Husin Alatas ◽  
Dyo D. Prayuda ◽  
Achmad Syafiuddin ◽  
May Parlindungan ◽  
Nurjaman O. Suhendra ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Large Scale ◽  
Inelastic Collision ◽  
River Flow ◽  
Equation Of Motion ◽  
Momentum Conservation ◽  
Digital Elevation ◽  
Computer Based ◽  
Elevation Model ◽  
Modified Equation

We propose a simple computer based phenomenological model to simulate the characteristics of river flow velocity in large scale. We use shuttle radar tomography mission based digital elevation model in grid form to define the terrain of catchment area. The model relies on mass-momentum conservation law and modified equation of motion of falling body in inclined plane. We assume inelastic collision occurs at every junction of two river branches to describe the dynamics of merged flow velocity.

scholarly journals Assessing Optimal Digital Elevation Model Selection for Active River Area Delineation Across Broad Regions

2021 ◽  
Author(s):  
Shizhou Ma ◽  
Karen Beazley ◽  
Patrick Nussey ◽  
Chris Greene
Keyword(s):  
High Resolution ◽  
Digital Elevation Model ◽  
Smoothing Algorithm ◽  
Processing Efficiency ◽  
Spatial Approach ◽  
Digital Elevation ◽  
Elevation Data ◽  
Computer Based ◽  
Lidar Dem ◽  
Elevation Model

Abstract The Active River Area (ARA) is a spatial approach for identifying the extent of functional riparian area. Given known limitations in terms of input elevation data quality and methodology, ARA studies to date have not achieved effective computer-based ARA-component delineation, limiting the efficacy of the ARA framework in terms of informing riparian conservation and management. To achieve framework refinement and determine the optimal input elevation data for future ARA studies, this study tested a novel Digital Elevation Model (DEM) smoothing algorithm and assessed ARA outputs derived from a range of DEMs for accuracy and efficiency. It was found that the tested DEM smoothing algorithm allows the ARA framework to take advantage of high-resolution LiDAR DEM and considerably improves the accuracy of high-resolution LiDAR DEM derived ARA results; smoothed LiDAR DEM in 5-meter spatial resolution best balanced ARA accuracy and data processing efficiency and is ultimately recommended for future ARA delineations across large regions.

scholarly journals Fusion Analysis of Optical Satellite Images and Digital Elevation Model for Quantifying Volume in Debris Flow Disaster

2019 ◽  
Vol 11 (9) ◽  
pp. 1096 ◽  
Author(s):  
Hiroyuki Miura
Keyword(s):  
Debris Flow ◽  
Digital Elevation Model ◽  
Large Scale ◽  
Satellite Images ◽  
Erosion Depth ◽  
Digital Elevation ◽  
Elevation Model ◽  
Fusion Analysis ◽  
Optical Satellite Images ◽  
Debris Flow Disaster

Rapid identification of affected areas and volumes in a large-scale debris flow disaster is important for early-stage recovery and debris management planning. This study introduces a methodology for fusion analysis of optical satellite images and digital elevation model (DEM) for simplified quantification of volumes in a debris flow event. The LiDAR data, the pre- and post-event Sentinel-2 images and the pre-event DEM in Hiroshima, Japan affected by the debris flow disaster on July 2018 are analyzed in this study. Erosion depth by the debris flows is empirically modeled from the pre- and post-event LiDAR-derived DEMs. Erosion areas are detected from the change detection of the satellite images and the DEM-based debris flow propagation analysis by providing predefined sources. The volumes and their pattern are estimated from the detected erosion areas by multiplying the empirical erosion depth. The result of the volume estimations show good agreement with the LiDAR-derived volumes.

A new method for supporting interpretation of paleochannels in a large scale — Detrended Digital Elevation Model Interpretation

Geomorphology ◽  
2020 ◽  
Vol 369 ◽  
pp. 107374
Author(s):  
Shuyan Zhang ◽  
Yong Ma ◽  
Fu Chen ◽  
Jianbo Liu ◽  
Fulong Chen ◽  
...  
Keyword(s):  
Digital Elevation Model ◽  
Large Scale ◽  
New Method ◽  
Model Interpretation ◽  
Digital Elevation ◽  
Elevation Model

scholarly journals A Semiautomatic Pixel-Object Method for Detecting Landslides Using Multitemporal ALOS-2 Intensity Images

2020 ◽  
Vol 12 (3) ◽  
pp. 561 ◽  
Author(s):  
Bruno Adriano ◽  
Naoto Yokoya ◽  
Hiroyuki Miura ◽  
Masashi Matsuoka ◽  
Shunichi Koshimura
Keyword(s):  
Disaster Response ◽  
Large Scale ◽  
Reference Data ◽  
Mass Movement ◽  
Recovery Planning ◽  
Additional Information ◽  
Digital Elevation ◽  
Before And After ◽  
Intensity Images ◽  
Elevation Model

The rapid and accurate mapping of large-scale landslides and other mass movement disasters is crucial for prompt disaster response efforts and immediate recovery planning. As such, remote sensing information, especially from synthetic aperture radar (SAR) sensors, has significant advantages over cloud-covered optical imagery and conventional field survey campaigns. In this work, we introduced an integrated pixel-object image analysis framework for landslide recognition using SAR data. The robustness of our proposed methodology was demonstrated by mapping two different source-induced landslide events, namely, the debris flows following the torrential rainfall that fell over Hiroshima, Japan, in early July 2018 and the coseismic landslide that followed the 2018 Mw6.7 Hokkaido earthquake. For both events, only a pair of SAR images acquired before and after each disaster by the Advanced Land Observing Satellite-2 (ALOS-2) was used. Additional information, such as digital elevation model (DEM) and land cover information, was employed only to constrain the damage detected in the affected areas. We verified the accuracy of our method by comparing it with the available reference data. The detection results showed an acceptable correlation with the reference data in terms of the locations of damage. Numerical evaluations indicated that our methodology could detect landslides with an accuracy exceeding 80%. In addition, the kappa coefficients for the Hiroshima and Hokkaido events were 0.30 and 0.47, respectively.

Food Submergence Calculation and Analysis Using Digital Elevation Model and Geographical Information System

2014 ◽  
Vol 571-572 ◽  
pp. 792-795
Author(s):  
Xiao Qing Zhang ◽  
Kun Hua Wu
Keyword(s):  
Information System ◽  
Digital Elevation Model ◽  
Flood Control ◽  
Large Scale ◽  
Geographical Information ◽  
Economic Losses ◽  
Model Data ◽  
Digital Elevation ◽  
Elevation Model ◽  
Digital Elevation Model Data

Floods usually cause large-scale loss of human life and wide spread damage to properties. Determining flood zone is the core of flood damage assessment and flood control decision. The aim of this paper is to delineate the flood inundation area and estimate economic losses arising from flood using the digital elevation model data and geographic information system techniques. Flood extent estimation showed that digital elevation model data is very precious to model inundation, however, in order to be spatially explicit flood model, high resolution DEM is necessary. Finally, Analyses for the submergence area calculation accuracy.

scholarly journals Morphotectonic analysis of Kozani Basin (Western Macedonia, Greece)

2017 ◽  
Vol 47 (2) ◽  
pp. 657
Author(s):  
E. Simou ◽  
V. Karagkouni ◽  
G. Papantoniou ◽  
D. Papanikolaou ◽  
P. Nomikou
Keyword(s):  
Large Scale ◽  
Drainage Pattern ◽  
Tectonic Structure ◽  
Tectonic Structures ◽  
River Terraces ◽  
Digital Elevation ◽  
Combined Use ◽  
Digital Modelling ◽  
Elevation Model ◽  
Topographic Relief

Kozani Basin is located in northern-central Greece and constitutes the southernmost of the Plio-Pleistocene basins of western Macedonia. Quantitative and qualitative analysis of morphological slope values, as well as the analysis of the drainage pattern in Kozani Basin confirms that the current topographic relief reflects intense neotectonic activity. Synthetic Morphotectonic Map of the under study area was carried out by means of the combined use of: (a) Digital Elevation Model (DEM), (b) Slope Distribution Map, (c) Morphological Slope Map and (d) Drainage Pattern Map. The composition of the digital modelling in conjunction with the regional geological setting, allows the identification of the main morphological discontinuities and lineaments that result from morphotectonic interpretation. The high morphological slope values indicate well-defined morphotectonic features, which mainly trend NE - SW and, secondarily, NW - SE. Distinct tectonic structures are mostly recognized in the SE margin of Kozani Basin, which is characterized by intense topographic relief. The main large-scale tectonic structure trends NE - SW and corresponds to the major Aliakmonas marginal fault zone that bounds the Kozani basin to the south. On the other hand, the NW margin’s features are indiscernible; thus, the criteria for their recognition are based on the existence of the river terraces, which reflect the tectonic control. The results of our studies are presented on the Morphotectonic Map, which is followed by our 3D model of Kozani Basin.

scholarly journals Flood Impact Assessment Using HEC-RAS and GIS Techniques Dinder River, Southeast Sudan

2021 ◽  
Vol 1 (3) ◽  
pp. 14-19
Keyword(s):  
River Flow ◽  
Flow Behavior ◽  
Normal Height ◽  
Discharge Data ◽  
Four Seasons ◽  
Statistical Computation ◽  
Digital Elevation ◽  
Gis Environment ◽  
Flooded Area ◽  
Elevation Model

Abstract: Dinder River is largest tributary of the Blue Nile. It is seasonal river that flows from June to November and reaches its high peak in September. Frequently, the water level exceeds the normal height causing over bank flow and consequently floods. The floods generally ring about losses properties and crops close to river banks. This study is attempts to figure out the river flow behavior and find out the aerial extent of inundated lands in four flooding seasons. The investigated area is located in Sennar State, SE Sudan. Discharge data collected over the period from 2015 to 2018 and Digital Elevation Model (DEM) have been used to model the River flow regime, while land cover data was used to determine the affected LU/LC types in the area. HEC-RAS software was used to create 2D unsteady flow model in order to simulate Dinder River flooded area in four seasons. The largest flooded area extent in each season was used as input in GIS environment for further spatial analysis. Statistical computation for the affected area and consequent analysis revealed that: the affected urban area in 2018 was around 28.152km2, in 2017 was 29.205 km2, in 2016 was 16.531km2, and in 2015 was 10.422km2. Similar calculations were carried out for the other LU/LC types. According to the present study, the year 2017 witnessed the largest extent of flooding in the area.

scholarly journals Global analysis of the slope of forest land

2020 ◽  
Author(s):  
Mikael Lundbäck ◽  
Henrik Persson ◽  
Carola Häggström ◽  
Tomas Nordfjell
Keyword(s):  
Large Scale ◽  
Forest Cover ◽  
Global Analysis ◽  
Forest Area ◽  
Forest Land ◽  
Digital Elevation ◽  
Total Forest Area ◽  
Cent Point ◽  
Elevation Model ◽  
Country Specific

Abstract Forests of the world constitute one-third of the total land area and are critical for e.g. carbon balance, biodiversity, water supply and as source for bio-based products. Although the terrain within forest land has a great impact on accessibility, there is a lack of knowledge about the distribution of its variation in slope. The aim was to address that knowledge gap and create a globally consistent dataset of the distribution and area of forest land within different slope classes. A Geographic Information System (GIS) analysis was performed using the open-source QGIS, GDAL and R software. The core of the analysis was a digital elevation model and a forest cover mask, both with a final resolution of 90 m. The total forest area according to the forest mask was 4.15 billion hectares whereof 82 per cent was on slope < 15°. The remaining 18 per cent was distributed over the following slope classes, with 6 per cent on a 15–20° slope, 8 per cent on a 20–30° slope and 4 per cent on a slope > 30°. Out of the major forestry countries, China had the largest proportion of forest steeper than 15° followed by Chile and India. A sensitivity analysis with 20 m resolution resulted in increased steep areas by 1 per cent point in flat Sweden and by 11 per cent points in steep Austria. In addition to country-specific and aggregated results of slope distribution and forest area, a global raster dataset is also made freely available to cover user-specific areas that are not necessarily demarcated by country borders. Apart from predicting the regional possibilities for different harvesting equipment, which was the original idea behind this study, the results can be used to relate geographical forest variables to slope. The results could also be used in strategic forest fire fighting and large-scale planning of forest conservation and management.

scholarly journals Kajian Potensi Erosi Di Daerah Aliran Sungai Babon Menggunakan Permodelan GeoWEPP

G - SMART ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 98
Author(s):  
Revangga Dandha Pratama ◽  
Dimas Jalu Setyawan ◽  
Budi Santosa
Keyword(s):  
Erosion Rate ◽  
River Flow ◽  
Water Erosion ◽  
Climate Data ◽  
Erosion Prediction ◽  
Digital Elevation ◽  
Water Erosion Prediction Project ◽  
Type Data ◽  
Hazard Level ◽  
Elevation Model

At the time of the high intensity of rainfall in Semarang, the water contained in the Babon River had overflowed, resulting in flooding of parts of the area adjacent to the Babon river flow. This matter has many factors, there are erosion and sediment produced. This study aims to study erosion potential in the Babon watershed, using the Geospatial Interface for Water Erosion Prediction Project (GeoWEPP) modeling. The results of the modeling are the amount of erosion rate and erosion distribution in the study area. The erosion prediction period in this study is in 2006 - 2015. Data needed in GeoWEPP operation are Digital Elevation Model, climate data, land use data, and soil type data. Based on the GeoWEPP process in the Babon watershed the erosion rate was 36.1 tons / ha / year and the sediment yield was 26075.2 tons / year. From the results of the erosion rate produced divided by the reasonable erosion rate get the Erosion Hazard Level index (TBE) of 3.6 or including medium TBE. Based on the distribution of erosion maps produced, the area experienced the greatest erosion rate in the Ungaran region. This is due to the fact that it belongs to the highlands and has a high slope value.

Sentinel-1 InSAR data by LiCSAR system

2021 ◽  
Author(s):  
Milan Lazecky ◽  
Yasser Maghsoudi Mehrani ◽  
Scott Watson ◽  
Yu Morishita ◽  
John Elliott ◽  
...  
Keyword(s):  
Time Series ◽  
Large Scale ◽  
Atmospheric Correction ◽  
East African ◽  
Digital Elevation ◽  
African Rift ◽  
Earth Observation Satellites ◽  
Elevation Model ◽  
Data Coherence ◽  
Standard Frame

<p>Looking Into the Continents from Space with Synthetic Aperture Radar (LiCSAR) is a system built for large-scale interferometric processing of Sentinel-1 data. LiCSAR automatically produces geocoded wrapped and unwrapped interferograms combining every acquisition epoch with four preceding epochs, and complementary data (coherence, amplitude, line-of-sight unit vectors, digital elevation model, metadata, and atmospheric phase screen estimates by the Generic Atmospheric Correction Online Service, GACOS).</p><p>The LiCSAR products are generated in frame units where a standard frame covers ~220x250 km, at 0.001° resolution (WGS-84 coordinate system). Frames are continuously updated for tectonic and volcanic priority areas. In 2020, the LiCSAR system covered about 1,500 global frames in which we have processed over 89,000 Sentinel-1 acquisitions and generated over 300,000 interferograms. Among these, 470 frames cover 1,024 global volcanoes. We aim to cover the global seismic mask defined by the Committee on Earth Observation Satellites (CEOS), but focus initially on the Alpine-Himalayan belt and East African Rift.</p><p>We serve the products as open and freely accessible through our web portal: https://comet.nerc.ac.uk/comet-lics-portal and aim to provide them to shared infrastructures as the European Plate Observing System (EPOS). We also generate rapid response coseismic interferograms for earthquakes with moment magnitude (Mw)> 5.5  a few hours after the postseismic data become available, and we update frames covering active volcanoes twice per day.</p><p>Our products can be directly converted to displacement time series and velocities using  the LiCSBAS time series analysis software. We present solutions implemented in LiCSAR, and show several case studies that use LiCSAR and LiCSBAS products to measure tectonic and volcanic deformation.</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.1c122b867cff59390830161/sdaolpUECMynit/12UGE&app=m&a=0&c=02895a62108de9393057db6a355e3b06&ct=x&pn=gnp.elif&d=1" alt=""></p>

Sign in / Sign up

Export Citation Format

Share Document