The spatially distributed nature of subglacial sediment dynamics: using a numerical model to quantify sediment transport and bedrock erosion across a glacier bed in response to glacier behavior and hydrology

Abstract. In addition to ice and water, glaciers expel sediment. As a result, changing glacier dynamics and melt will result in changes to glacier erosion and sediment discharge, which can impact the landscape surrounding retreating glaciers, as well as communities and ecosystems downstream. To date, the available models of subglacial sediment transport on the sub-hourly to decadal-scale exist in one dimension, usually along a glacier's flow line. Such models have proven useful in describing the formation of landforms, the impact of sediment transport on glacier dynamics, the interactions between climate, glacier dynamics, and erosion. However, because of the large role of sediment connectivity in determining sediment discharge, the geoscience community needs modeling frameworks that describe subglacial sediment discharge in two spatial dimensions over time. Here, we present SUGSET_2D, a numerical model that evolves a two-dimensional subglacial till layer in response to the erosion of bedrock and changing sediment transport conditions below the glacier. Experiments employed on test cases of synthetic ice sheets and alpine glaciers demonstrate the heterogeneity in sediment transport across a glacier's bed. Furthermore, the experiments show the non-linear increase in sediment discharge following increased glacier melt. Lastly, we apply the model to Griesgletscher in the Swiss Alps where we use a parameter search to test model outputs against annual observations of sediment discharge measured from the glacier. The model captures the glacier's inter-annual variability and quantities of sediment discharge. Furthermore, the model's capacity to represent the data depends greatly on the grain size of sediment. Smaller sediment sizes allow sediment transport to occur in regions of the bed with reduced water flow and channel size, effectively increasing sediment connectivity into the main channels. Model outputs from the three test-cases together show the importance of considering heterogeneities in water discharge and sediment availability in two dimensions.

Download Full-text

Coastal Sediment Transport along Kalpakkam using Sediment Trend Exploaration and Numerical Modelling

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b1386.0982s1119 ◽

2019 ◽

Vol 8 (2S11) ◽

pp. 3011-3015

Keyword(s):

Grain Size ◽

Sediment Transport ◽

Numerical Model ◽

Numerical Modelling ◽

Trend Analysis ◽

Coastal Sediment ◽

Sediment Grain Size ◽

Coastal Sediment Transport ◽

The Impact ◽

Grain Size Trend Analysis

The impact of coastal sediment transport in the nearshore region is significant and the need for improved sediment quantification techniques appears to be universally accepted. The coastal sediment transport models presently in use were derived empirically from very sparse measurements of waves and currents and from laboratory experiments. The shoreline of Kadalur fishing villages near Kalpakkam has been experiencing erosion due to occurrence of cyclones every monsoon. Palar River with its confluence in the Bay of Bengal at the northern tip of the Kadalur villages has its mouth closed due to negligible river flow. The purpose of this study is to assess sediment dynamics in the Kalpakkam coast using two independent approaches; namely Sediment Trend Analysis (STA) and two dimensional numerical modelling. The latter can track the movement of individual particles. Numerical modelling approach is based on Delft3D model which allows the coupling of flow and wave modules. STA and numerical modelling results can provide sediment transport direction. The combination of both approaches provides a means of verification of sedimentation processes. The basic assumption in STA is that sediment transport can be responsible for the differences in sediment grain size distributions. For Grain Size Trend Analysis, grab samples were collected throughout the nearshore area. Grain Size Trend Analysis was then carried out and subsequent results were plotted to obtain the sediment transport pattern for the region. The results obtained are compared with the numerical model results and also used for validation of sediment transport evaluated using the numerical model.

Download Full-text

A NUMERICAL MODEL FOR SEDIMENT TRANSPORT

Coastal Engineering Proceedings ◽

10.9753/icce.v16.103 ◽

1978 ◽

Vol 1 (16) ◽

pp. 103

Author(s):

J.P. Lepetit ◽

A. Hauguel

Keyword(s):

Sediment Transport ◽

Numerical Model ◽

Time Scale ◽

Local Scour ◽

Two Dimensional ◽

Dimensional Model ◽

Propagation Equation ◽

Coastal Structure ◽

Two Dimensional Model ◽

The Impact

We introduce here a numerical two dimensional model for sediment transport which permits to compute the impact of a coastal structure on the bottom evolution. The introduction of current disturbance and some assumptions using difference of time scale between current and bottom evolutions permits to obtain a propagation equation driving the bottom evolution. The model has been calibrated in the case of the local scour around a jetty. At last, it has been applied to the bottom evolution in the vicinity of the new port of Dunkerque.

Download Full-text

Simulation of ion migration in perovskite solar cells using a kinetic Monte Carlo/drift diffusion numerical model and analysis of the impact on device performance

10.29363/nanoge.hopv.2018.099 ◽

2018 ◽

Author(s):

Alessio Gagliardi ◽

Ajay Singh ◽

Waldemar Kaiser

Keyword(s):

Monte Carlo ◽

Solar Cells ◽

Numerical Model ◽

Kinetic Monte Carlo ◽

Perovskite Solar Cells ◽

Device Performance ◽

Drift Diffusion ◽

Ion Migration ◽

The Impact

Download Full-text

A Model for the Thermal Behaviour of an Offshore Cable Installed in a J-Tube

Proceedings ◽

10.3390/wef-06936 ◽

2020 ◽

Vol 58 (1) ◽

pp. 31

Author(s):

Jeremy Arancio ◽

Ahmed Ould El Moctar ◽

Minh Nguyen Tuan ◽

Faradj Tayat ◽

Jean-Philippe Roques

Keyword(s):

Sensitivity Analysis ◽

Numerical Model ◽

Thermal Behaviour ◽

Energy Production ◽

Power Transmission ◽

Temperature Fields ◽

Sobol Indices ◽

Lumped Element ◽

Thermal Phenomena ◽

The Impact

In the race for energy production, supplier companies are concerned by the thermal rating of offshore cables installed in a J-tube, not covered by IEC 60287 standards, and are now looking for solutions to optimize this type of system. This paper presents a numerical model capable of calculating temperature fields of a power transmission cable installed in a J-tube, based on the lumped element method. This model is validated against the existing literature. A sensitivity analysis performed using Sobol indices is then presented in order to understand the impact of the different parameters involved in the heating of the cable. This analysis provides an understanding of the thermal phenomena in the J-tube and paves the way for potential technical and economic solutions to increase the ampacity of offshore cables installed in a J-tube.

Download Full-text

Modelling river bank erosion using a 2D depth-averaged numerical model of flow and non-cohesive, non-uniform sediment transport

Advances in Water Resources ◽

10.1016/j.advwatres.2015.11.004 ◽

2016 ◽

Vol 93 ◽

pp. 75-88 ◽

Cited By ~ 22

Author(s):

Kamal El Kadi Abderrezzak ◽

Andrés Die Moran ◽

Pablo Tassi ◽

Riadh Ata ◽

Jean-Michel Hervouet

Keyword(s):

Sediment Transport ◽

Numerical Model ◽

Bank Erosion ◽

River Bank ◽

River Bank Erosion

Download Full-text

Transmission of solar radiation through clouds on melting glaciers: a comparison of parameterizations and their impact on melt modelling

Journal of Glaciology ◽

10.3189/002214311796406013 ◽

2011 ◽

Vol 57 (202) ◽

pp. 367-381 ◽

Cited By ~ 42

Author(s):

Francesca Pellicciotti ◽

Thomas Raschle ◽

Thomas Huerlimann ◽

Marco Carenzo ◽

Paolo Burlando

Keyword(s):

Solar Radiation ◽

Air Temperature ◽

Radiative Forcing ◽

Model Performance ◽

Horizontal Resolution ◽

Swiss Alps ◽

Cloud Radiative Forcing ◽

Correct Definition ◽

Diurnal Range ◽

The Impact

AbstractWe explore the robustness and transferability of parameterizations of cloud radiative forcing used in glacier melt models at two sites in the Swiss Alps. We also look at the rationale behind some of the most commonly used approaches, and explore the relationship between cloud transmittance and several standard meteorological variables. The 2 m air-temperature diurnal range is the best predictor of variations in cloud transmittance. However, linear and exponential parameterizations can only explain 30–50% of the observed variance in computed cloud transmittance factors. We examine the impact of modelled cloud transmittance factors on both solar radiation and ablation rates computed with an enhanced temperature-index model. The melt model performance decreases when modelled radiation is used, the reduction being due to an underestimation of incoming solar radiation on clear-sky days. The model works well under overcast conditions. We also seek alternatives to the use of in situ ground data. However, outputs from an atmospheric model (2.2 km horizontal resolution) do not seem to provide an alternative to the parameterizations of cloud radiative forcing based on observations of air temperature at glacier automatic weather stations. Conversely, the correct definition of overcast conditions is important.

Download Full-text

Application of a 3D Layer Integrated Numerical Model of Flow and Sediment Transport Processes to a Reservoir

Water ◽

10.3390/w7105239 ◽

2015 ◽

Vol 7 (10) ◽

pp. 5239-5257 ◽

Cited By ~ 8

Author(s):

Shervin Faghihirad ◽

Binliang Lin ◽

Roger Falconer

Keyword(s):

Sediment Transport ◽

Numerical Model ◽

Transport Processes ◽

Flow And Sediment Transport

Download Full-text

Fractality of Simulated Fracture

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.409.154 ◽

2009 ◽

Vol 409 ◽

pp. 154-160 ◽

Cited By ~ 2

Author(s):

Petr Frantík ◽

Zbyněk Keršner ◽

Václav Veselý ◽

Ladislav Řoutil

Keyword(s):

Numerical Model ◽

Elastic Plate ◽

Model Simulation ◽

Element Model ◽

The Other ◽

Particle Model ◽

Discrete Element Model ◽

Fractal Nature ◽

Discrete Elements ◽

The Impact

The paper is focussed on numerical simulations of the fracture of a quasi-brittle specimen due to its impact onto a fixed rigid elastic plate. The failure of the specimen after the impact is modelled in two ways based on the physical discretization of continuum: via physical discrete elements and pseudo-particles. Advantages and drawbacks of both used methods are discussed. The size distribution of the fragments of the broken specimen resulting from physical discrete element model simulation follows a power law, which indicates the ability of the numerical model to identify the fractal nature of the fracture. The pseudo-particle model, on the other side, can successfully predict the kinematics of the fragments of the specimen under impact failure.

Download Full-text