The EU Center of Excellence for Exascale in Solid Earth (ChEESE): Implementation, results, and roadmap for the second phase

publishedVersio

Comparison of Land Building by Mississippi River Diversion Using One and Two Dimensional Numerical Models

River sediment diversions have been identified as one strategy for creating new land and offsetting Mississippi River delta plain land loss. Numerical modeling is one tool for estimating the amount of land, geomorphic features and ecological benefits from diversions. There are a number of models proposed to estimate sediment diversion land building, ranging from simplistic approaches that provide bulk characteristics and use little computational resources to process-based models that require a large amount of input parameters and computing power. This thesis aims to compare and contrast two approaches to simulating the land building processes in a simplified receiving basin: a 1D spatially averaged model; and a horizontal 2D, process-based Delft3D model. Four scenarios were run: three with varying amounts of non-cohesive sediment; and one with a mixture of non-cohesive and cohesive sediment. A number of simplifying assumptions were made for more direct comparisons of the bulk and detailed delta properties and the computational resources. These included the bulking of cohesive and non-cohesive sediments on deposition are assumed equal; erosion below the pre-delta strata is not allowed; and the river sediment diversion operates continuously at a given flow and sediment concentration. Note that this last assumption was made for easier model comparisons and not how any proposed diversions would be operated. Distributary channel network information, missing in the 1D model but important for ecohydrological processes, is extracted from the 2D model. The 1D model took less than one minute to simulate the same scenario that required over 20 hours on 32 processors using the 2D model. Results showed the 1D model delta radii and areas were always larger, but relatively close, to those simulated by the 2D model, particularly for non-cohesive sediments. The deltas formed from solely non-cohesive sediments had numerous short, but wide, channels and were roughly fan shaped, thus justifying the radial symmetry assumption of the 1D model. The ratios of the 2D to 1D model delta areas were 70% and 55% for non-cohesive and mixed scenarios, respectively. The 2D model results showed that presence of cohesive sediment promoted narrower and weakly sinuous channels that affect delta growth dynamics and result in increased vertical aggradation, thus limiting the area of land built

Ground-based synthetic aperture radar (GBSAR) interferometry for deformation monitoring

Ph. D ThesisGround-based synthetic aperture radar (GBSAR), together with interferometry, represents a powerful tool for deformation monitoring. GBSAR has inherent flexibility, allowing data to be collected with adjustable temporal resolutions through either continuous or discontinuous mode. The goal of this research is to develop a framework to effectively utilise GBSAR for deformation monitoring in both modes, with the emphasis on accuracy, robustness, and real-time capability. To achieve this goal, advanced Interferometric SAR (InSAR) processing algorithms have been proposed to address existing issues in conventional interferometry for GBSAR deformation monitoring. The proposed interferometric algorithms include a new non-local method for the accurate estimation of coherence and interferometric phase, a new approach to selecting coherent pixels with the aim of maximising the density of selected pixels and optimizing the reliability of time series analysis, and a rigorous model for the correction of atmospheric and repositioning errors. On the basis of these algorithms, two complete interferometric processing chains have been developed: one for continuous and the other for discontinuous GBSAR deformation monitoring. The continuous chain is able to process infinite incoming images in real time and extract the evolution of surface movements through temporally coherent pixels. The discontinuous chain integrates additional automatic coregistration of images and correction of repositioning errors between different campaigns. Successful deformation monitoring applications have been completed, including three continuous (a dune, a bridge, and a coastal cliff) and one discontinuous (a hillside), which have demonstrated the feasibility and effectiveness of the presented algorithms and chains for high-accuracy GBSAR interferometric measurement. Significant deformation signals were detected from the three continuous applications and no deformation from the discontinuous. The achieved results are justified quantitatively via a defined precision indicator for the time series estimation and validated qualitatively via a priori knowledge of these observing sites.China Scholarship Council (CSC), Newcastle Universit

Shallow Water Equations in Hydraulics: Modeling, Numerics and Applications

This Special Issue aims to provide a forum for the latest advances in hydraulic modeling based on the use of shallow water and related models as well as their novel application in practical engineering. Original contributions, including those in but not limited to the following areas, will be considered for publication: new conceptual models and applications, flood inundation and routing, sediment transport and morphodynamic modelling, pollutant transport in water, irrigation and drainage modeling, numerical simulation in hydraulics, novel numerical methods for the shallow water equations and extended models, case studies, and high-performance computing