Creative computing with Landlab: an open-source toolkit for building, coupling, and exploring two-dimensional numerical models of Earth-surface dynamics

Abstract

The ability to model surface processes and to couple them to both subsurface and atmospheric regimes has proven invaluable to research in the Earth and planetary sciences. However, creating a new model typically demands a very large investment of time, and modifying an existing model to address a new problem typically means the new work is constrained 15 to its detriment by model adaptations for a different problem. Landlab is an open-source software framework explicitly designed to accelerate the development of new process models by providing: 1. a set of tools and existing grid structuresincluding both regular and irregular grids -to make it faster and easier to develop new process components, or numerical implementations of physical processes; 2. a suite of stable, modular, and interoperable process components that can be combined to create an integrated model; and 3. a set of tools for data input, output, manipulation, and visualization. A set of 20 example models built with these components is also provided. Landlab's structure makes it ideal not only for fully developed modelling applications, but also for model prototyping and classroom use. Because of its modular nature, it can also act as a platform for model intercomparison and epistemic uncertainty and sensitivity analyses. Landlab exposes a standardized model interoperability interface, and is able to couple to third party models and software. Landlab also offers tools to allow the creation of cellular automata, and allows native coupling of such models to more traditional continuous differential 25 equation-based modules. We illustrate the principles of component coupling in Landlab using a model of landform evolution, a cellular ecohydrologic model, and a flood-wave routing model. Earth Surf. Dynam. Discuss., 2. Functions to operate on the values defined on such a grid, enabling the solution of time-dependent numerical algorithms across them (e.g., differential equations, cellular automata); 3. A mechanism for the control of boundary conditions across a grid; 4. Encapsulation of conceptual models for individual Earth-surface processes into reusable components, with a standard interface that allows operation across Landlab grids; 5 5. The ability to build a multi-process model by combining together components; 6. The ability to quickly and efficiently build new components, and to couple them with those components already in the library. 7. A straightforward and standardized input and output interface, including the ability to import from and export to common spatially distributed data formats such as NetCDF and ESRI ASCII, and a plotting module. This interface 10 also enables coupling to third party models and software.

Observation and Simulation of Solid Sedimentary Flux: Examples From Northwest Africa

“…We note that the deposition of post‐Miocene clastic sedimentary rock in the Mauritanian basin has led to the formation of important hydrocarbon reservoirs. In the future more complete landscape models could be parametrized using the calculated history of uplift to predict histories of volumetric sedimentary flux (e.g., Landlab: Hobley et al, ; Badlands: Salles et al, ).…”

Controls on Zero‐Order Basin Morphology

“…Uniform valley spacing and a uniformity of drainage area can be observed in many landscape evolution models (e.g., Hobley et al, ; Tucker et al, ) and are predicted in many theories of landscape evolution (Perron et al, ), and drainage basins extracted from such models are typically elliptical in morphology. When contrasted with measurements of zero‐order basins extracted from high‐resolution topography, the disparity between the two is apparent, with extracted basins exhibiting much more variability than their modeled counterparts.…”

Impact of vegetation on erosion: Insights from the calibration and test of a landscape evolution model in alpine badland catchments

“…Landlab is an open‐source Python library for building two‐dimensional, grid‐based numerical models (Hobley et al. ). It provides various components to compute erosion fluxes according to different processes across a gridded terrain.…”

“…Drainage routing is computed using a steepest‐slope flow routing algorithm (implemented using the Landlab FlowDirector and FlowAccumulator components; Hobley et al. ), and is not updated over the duration of the simulations (1 year).…”