Project institution: University of Glasgow
Project supervisor(s): Prof Todd Ehlers (University of Glasgow), Dr Jingtao Lai (University of Glasgow), Prof Lukasz Kaczmarczyk (University of Glasgow) and Dr Adam Smith (University of Glasgow),
Overview and Background
Global climate and environmental change increasingly result in weather extremes that impact society and infrastructure. These extremes include stormier climates with increased wind speeds, precipitation events or drought, and temperatures (amongst other things). A team of University of Glasgow researchers are developing an Earth systems digital twin for exascale computing that works on GPU computers and uses weather forecasts to predict the cascading effect of climate change events on environmental systems. Our goal is to provide predictions at the national or larger scale for the impacts of environmental extremes on natural and urban settings. This project is one, stand alone, component of this larger scale project.
In this project you will develop and apply a landscape evolution model component of the Earth system model. We seek a student interested in surface water hydrology and landscape evolution modeling of rivers and hillslopes across Scotland. The student will develop software for investigating how weather forecasts and extreme weather events interact with geomorphic, hydrologic, and biosphere processes. Students from diverse backgrounds (e.g., geo- or hydrological sciences, engineering, maths, computer science) are welcome to apply to this project. The supervision team will take your background into account when setting the dissertation goals and provide mechanisms to lear the background information need to fill in knowledge gaps.
Your job while working on this project will involve software development for simulating the relevant physical processes, applying the model to historic data for model evaluation, working in a team/workgroup environment, attending regular research group seminars, integrating diverse environmental and satellite data into your software, and learning new techniques through ExaGEO training workshops.
Methodology and Objectives
Methods used in this project involved in the first year include the development of a GPU based numerical model that calculates surface water budgets (runoff, infiltration, etc) and applies the model to understand erosion, transport, and deposition of sediments as a function of fluvial and hillslope processes. The model will use meteorological forecasts, digital topography, vegetation cover, and soil/rock cover as inputs and will forecast river discharge and erosion/sedimentation. The final years of the project involve improving the model to incorporate different environmental data such as remote sensing data for land use, biota, and hydrology.
Teaser Project 1:
This teaser project, conducted in the first year, will focus on development of a GPU based flow routing algorithm for application to Digital Elevation Model (DEM) data. The focus of the project is on understanding how precipitation that falls on a landscape during different weather events will influence the amount and rate of water moving over a landscape and the resulting river discharge. The calculation of the overland flow of water and river discharge are important for understanding (see teaser project 2) what types of rainfall events lead to the mobilization of sediment and river transport, or saturation of hillslope regolith and mass wasting (landslide) events. This project will be done for large geographic regions and optimized for domain decomposition on a GPU cluster. Existing open source software (non-GPU based) exists for addressing this problem and can provide a template for development of a GPU-based version.
Initial efforts will focus on the identification of catchment boundaries and calculation of river runoff for different spatial and temporal distributions of precipitation. Time permitting, additional components of the hydrologic cycle will be added including infiltration rates as a function of different soil types, and evaporation, evapotranspiration, and snowpack melting processes. After implementing one or more of the previous configurations, the program will be applied to past meteorological events in Scotland and compared to observed river discharge.
Teaser Project 2:
This teaser project, also conducted in the first year, focuses on development of GPU software to calculate how water flowing over landscapes (overland flow) and in rivers (discharge) entrains and erodes the underlying soil, sediment, or bedrock. This project is important because projected climate change will result in more intense rainfall events that could lead to increased erosion rates, and higher sediment concentrations in rivers. For example, increased soil erosion removes nutrients needed by the biosphere and impacts agriculture practices. Too much soil erosion could therefore impact biodiversity and food security. At the start of this project you will work through learning tutorials from existing (non-GPU based) software to acquire an overview of the ‘big picture’ of processes you will address. Initial new and development efforts in this project will focus on calculating the calculating the shear stress of different amounts and velocities of water moving over a digital elevation model. These calculations will be used to determine, for different intensities of rainfall, how much sediment and rock is entrained in the flow and moved downslope. The goal would be the fast and efficient calculation of erosion rates across a landscape for different distributions of precipitation. Time permitting, the next steps of the project would include consideration of detachment/transport limiting conditions within the model and identification of where and when either erosion or deposition occur. Additional factors that can be taken into account are how different vegetation and soil types influence erosion, and including remote sensing data as model inputs for the selection of erosion related model parameters.
An example movie of the different components of this project and how a landscape evolution model works is available here.
References and Further Reading
- Sharma, H. and Ehlers, T. A.: Effects of seasonal variations in vegetation and precipitation on catchment erosion rates along a climate and ecological gradient: insights from numerical modeling, Earth Surf. Dynam., 11, 1161–1181, 2023 (click here)
- Schmid, M., Ehlers, T. A., Werner, C., Hickler, T., and Fuentes-Espoz, J.-P.: Effect of changing vegetation and precipitation on denudation – Part 2: Predicted landscape response to transient climate and vegetation cover over millennial to million-year timescales, Earth Surface Dynamics, 6, 859–881, 2018 (click here)
- Hobley, D. E. J., Adams, J. M., Nudurupati, S. S., Hutton, E. W. H., Gasparini, N. M., Istanbulluoglu, E., and Tucker, G. E.: Creative computing with Landlab: an open-source toolkit for building, coupling, and exploring two-dimensional numerical models of Earth-surface dynamics, Earth Surface Dynamics, 5, 21–46, 2017 (click here)
