Collaborative Research: SI2-SSI: Landlab: A Flexible, Open-Source Modeling Framework for Earth-Surface Dynamics

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

Earth scientists discover and predict the behavior of the natural world in part through the use of computer models. Models are used to study a wide range of phenomena, such as soil erosion, flooding, plant growth, landslide occurrence, and many other processes. Models can be used to develop scientific understanding by comparing model calculations with the real world. They can also be used to make predictions about how nature will behave under certain conditions. In the areas of geosciences that deal with the earth's surface, one bottleneck in the development and use of models is the effort required to build, test, and debug the necessary software. This project contributes to scientific research and discovery by creating open source software tools that scientists can use to more efficiently create, modify, or combine computer models that represent portions of earth's surface and the processes occurring thereon. The project combines software development with user training and web-based resources, so that the products will be openly accessible, well documented, and widely disseminated within the relevant scientific communities. The project also contributes to K-12, undergraduate, and graduate-level education in computational modeling and earth-surface processes. This project catalyzes research in earth-surface dynamics by developing a software framework that enables rapid creation, refinement, and reuse of two-dimensional (2D) numerical models. The phrase earth-surface dynamics refers to a remarkably diverse group of science and engineering fields that deal with our planet's surface and near-surface environment: its processes, its management, and its responses to natural and human-made perturbations. Scientists who want to use an earth-surface model often build their own unique model from the ground up, re-coding the basic building blocks of their model rather than taking advantage of codes that have already been written. Whereas the end result may be novel software programs, many person-hours are lost rewriting existing code, and the resulting software is often idiosyncratic, poorly documented, and unable to interact with other software programs in the same scientific community and beyond, leading to lost opportunities for exploring an even wider array of scientific questions than those that can be addressed using a single model. The Landlab model framework seeks to eliminate these redundancies and lost opportunities, and simultaneously lower the bar for entry into numerical modeling, by creating a user- and developer-friendly software library that provides scientists with the fundamental building blocks needed for modeling earth-surface dynamics. The framework takes advantage of the fact that nearly all surface-dynamics models share a set of common software elements, despite the wide range of processes and scales that they encompass. Providing these elements in the context of a popular scientific programming environment, with strong user support and community engagement, contributes to accelerating progress in the diverse sciences of the earth's surface. The Landlab modeling framework is designed so that grid creation, data storage, and sharing of data among process components is done for the user. The framework is generic enough so that the coupling of two process components, whether they are squarely within a geoscience subdiscipline, or they cross subdisciplines, is the same. This architecture makes it easy to explore a wide range of questions in the geosciences without the need for much coding. Further, the model code is primarily written in Python, a language that is relatively easy for casual programmers to learn. Because of these attributes, the Landlab modeling framework has the potential to add computational modeling to the toolbox of a wide array of geoscientists, and to clear a path for trans-disciplinary earth-surface modeling that explores societally relevant topics, such as land-cover changes in response to climate change, as well as modeling of topics that currently require the coupling of sophisticated but harder-to-use models, such as sediment source-to-sink dynamics. The project will generate several proof-of-concept studies that are interesting in their own right, and demonstrate the capabilities of the modeling framework. Community engagement is fostered by presenting clinics and demonstrations at professional venues aimed at hydrologists, sedimentologists, critical zone scientists, and the broader earth and environmental sciences community. The team also supports visits by individual scientists for on-site training beyond these clinics. Input/output tools allow compatibility with data from relevant NSF-supported research. The project supports four graduate students and three postdoctoral researchers, and also includes modeling workshops for fifth to seventh grade girls in a community that has a greater than 50% minority population.