scholarly journals Impacts of Elevation Data Spatial Resolution on Two-Dimensional Dam Break Flood Simulation and Consequence Assessment

2014 ◽  
Vol 140 (2) ◽  
pp. 194-200 ◽  
Author(s):  
David R. Judi ◽  
Steven J. Burian ◽  
Timothy N. McPherson
Keyword(s):  
Spatial Resolution ◽  
Dam Break ◽  
Two Dimensional ◽  
Flood Simulation ◽  
Consequence Assessment ◽  
Elevation Data

Flood and Substance Transportation Analysis Using Satellite Elevation Data: A Case Study in Dhaka City, Bangladesh

2018 ◽  
Vol 13 (5) ◽  
pp. 967-977 ◽  
Author(s):  
Masakazu Hashimoto ◽  
Nozomu Yoneyama ◽  
Kenji Kawaike ◽  
Tomonori Deguchi ◽  
Mohammed Abed Hossain ◽  
...  
Keyword(s):  
The Other ◽  
Two Dimensional ◽  
Dhaka City ◽  
Flood Simulation ◽  
Aster Gdem ◽  
Elevation Data ◽  
Vertical Accuracy ◽  
Simulation Results ◽  
Better Than

This study investigated the vertical accuracy of satellite elevation data and its effect on flood and substance transportation analysis by using a two-dimensional flood simulation model. SRTM, AW3D, and ASTER GDEM satellite elevation data for East Dhaka, Bangladesh were used for evaluating the vertical accuracy and conducting numerical analyses. A case study in 2007 was simulated for the flooding analysis. The results showed that AW3D had the highest applicability because its vertical accuracy for low-lying areas was better than that of the other products. According to the differences in the flood extent of each satellite elevation data, the simulation results of the substance transportation analysis showed different spreading conditions. Furthermore, differences in the flood velocity and direction affected the distribution of the deposited substance.

scholarly journals Comparison of Three Different Parallel Computation Methods for a Two-Dimensional Dam-Break Model

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Shanghong Zhang ◽  
Wenda Li ◽  
Zhu Jing ◽  
Yujun Yi ◽  
Yong Zhao
Keyword(s):  
Parallel Computation ◽  
Data Exchange ◽  
Large Scale ◽  
Good Choice ◽  
Dam Break ◽  
Two Dimensional ◽  
Parallel Method ◽  
Parallel Methods ◽  
Storage Area ◽  
Speedup Factor

Three parallel methods (OpenMP, MPI, and OpenACC) are evaluated for the computation of a two-dimensional dam-break model using the explicit finite volume method. A dam-break event in the Pangtoupao flood storage area in China is selected as a case study to demonstrate the key technologies for implementing parallel computation. The subsequent acceleration of the methods is also evaluated. The simulation results show that the OpenMP and MPI parallel methods achieve a speedup factor of 9.8× and 5.1×, respectively, on a 32-core computer, whereas the OpenACC parallel method achieves a speedup factor of 20.7× on NVIDIA Tesla K20c graphics card. The results show that if the memory required by the dam-break simulation does not exceed the memory capacity of a single computer, the OpenMP parallel method is a good choice. Moreover, if GPU acceleration is used, the acceleration of the OpenACC parallel method is the best. Finally, the MPI parallel method is suitable for a model that requires little data exchange and large-scale calculation. This study compares the efficiency and methodology of accelerating algorithms for a dam-break model and can also be used as a reference for selecting the best acceleration method for a similar hydrodynamic model.

scholarly journals Magnetic domains and domain wall pinning in two-dimensional ferromagnets revealed by nanoscale imaging

2020 ◽  
Author(s):  
Qi-Chao Sun ◽  
Tiancheng Song ◽  
Eric Anderson ◽  
Tetyana Shalomayeva ◽  
Johannes Förster ◽  
...  
Keyword(s):  
Domain Structure ◽  
Spatial Resolution ◽  
Magnetic Domain ◽  
Magnetic Domain Structure ◽  
Nitrogen Vacancy ◽  
Two Dimensional ◽  
Magnetic Domains ◽  
Pinning Effect ◽  
Nitrogen Vacancy Center ◽  
Vacancy Center

Abstract Magnetic-domain structure and dynamics play an important role in understanding and controlling the magnetic properties of two-dimensional magnets, which are of interest to both fundamental studies and applications. However, the probe methods based on the spin-dependent optical permeability and electrical conductivity can neither provide quantitative information of the magnetization nor achieve nanoscale spatial resolution. These capabilities are essential to image and understand the rich properties of magnetic domains. Here, we employ cryogenic scanning magnetometry using a single-electron spin of a nitrogen-vacancy center in a diamond probe to unambiguously prove the existence of magnetic domains and study their dynamics in atomically thin CrBr3. The high spatial resolution of this technique enables imaging of magnetic domains and allows to resolve domain walls pinned by defects. By controlling the magnetic domain evolution as a function of magnetic field, we find that the pinning effect is a dominant coercivity mechanism with a saturation magnetization of about 26μB/nm2 for bilayer CrBr3. The magnetic-domain structure and pinning-effect dominated domain reversal process are verified by micromagnetic simulation. Our work highlights scanning nitrogen-vacancy center magnetometry as a quantitative probe to explore two-dimensional magnetism at the nanoscale.

scholarly journals High Spatial Resolution Neutron Transmission Imaging Using a Superconducting Two-Dimensional Detector

2021 ◽  
pp. 1-1
Author(s):  
Hiroaki Shishido ◽  
Kazuma Nishimura ◽  
The Dang Vu ◽  
Kazuya Aizawa ◽  
Kenji M Kojima ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Two Dimensional ◽  
Neutron Transmission ◽  
Transmission Imaging

Fog forecasting for Schiphol airport at sub-kilometre scale.  

2021 ◽  
Author(s):  
Gert-Jan Steeneveld ◽  
Roosmarijn Knol
Keyword(s):  
Spatial Resolution ◽  
Numerical Models ◽  
Wrf Model ◽  
Horizontal Resolution ◽  
Physical Processes ◽  
Radiation Fog ◽  
Fog Forecasting ◽  
Elevation Data ◽  
The Individual ◽  
The Impact

<p>Fog is a critical weather phenomenon for safety and operations in aviation. Unfortunately, the forecasting of radiation fog remains challenging due to the numerous physical processes that play a role and their complex interactions, in addition to the vertical and horizontal resolution of the numerical models. In this study we evaluate the performance of the Weather Research and Forecasting (WRF) model for a radiation fog event at Schiphol Amsterdam Airport (The Netherlands) and further develop the model towards a 100 m grid spacing. Hence we introduce high resolution land use and land elevation data. In addition we study the role of gravitational droplet settling, advection of TKE, top-down diffusion caused by strong radiative cooling at the fog top. Finally the impact of heat released by the terminal areas on the fog formation is studied. The model outcomes are evaluated against 1-min weather observations near multiple runways at the airport.</p><p>Overall we find the WRF model shows an reasonable timing of the fog onset and is well able to reproduce the visibility and meteorological conditions as observed during the case study. The model appears to be relatively insensitive to the activation of the individual physical processes. An increased spatial resolution to 100 m generally results in a better timing of the fog onset differences up to three hours, though not for all runways. The effect of the refined landuse dominates over the effect of refined elevation data. The modelled fog dissipation systematically occurs 3-4 h hours too early, regardless of physical processes or spatial resolution. Finally, the introduction of heat from terminal buildings delays the fog onset with a maximum of two hours, an overestimated visibility of 100-200 m and a decrease of the LWC with 0.10-0.15 g/kg compared to the reference.</p>

Studying 2D Materials with Advanced Raman Spectroscopy: CARS, SRS and TERS

2021 ◽  
Author(s):  
L Malard ◽  
Lucas Lafetá ◽  
Renan Cunha ◽  
Rafael Nadas ◽  
Andreij Gadelha ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Spatial Resolution ◽  
2D Materials ◽  
2D Systems ◽  
Weak Signal ◽  
Two Dimensional ◽  
Signal Response

Raman spectroscopy is established as a valuable tool to study and characterize two-dimensional (2D) systems, but it exhibits two drawbacks: a relatively weak signal response and a limited spatial resolution....

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