Development and Verification of a Numerical Library for Solving Global Terrestrial Multi‐Physics Problems

TitleDevelopment and Verification of a Numerical Library for Solving Global Terrestrial Multi‐Physics Problems
Publication TypeJournal Article
Year of Publication2019
JournalJournal of Advances in Modeling Earth Systems
Volume11
Date Published04/2019
Abstract / Summary

Current generation Land Surface Models (LSMs) routinely simulate many nonlinear multi‐physics processes. The complexity of future generation LSMs is expected to increase as critical new biophysical and biogeochemical processes are incorporated. Current generation LSMs have several shortcomings including the lack of robust numerical methods to solve discretized equations, monolithic software design that hinders testing of a process representation in isolation from other components, and absence of a flexible coupling framework to solve tightly coupled multi‐physics problems. While the LSMs community vigorously evaluates the accuracy of the conceptual model to represent reality (validation), the accuracy of the numerical implementation of the conceptual model (verification) is seldom examined. Method of Manufactured Solutions (MMS) is a technique for verifying complex codes when analytical solutions are unavailable. In this work, we present a standalone, open source numerical library for solving global terrestrial multi‐physics processes that includes a flexible coupling framework. Robust numerical solution for linear and nonlinear equations is provided via the PETSc library. We verify the numerical library using MMS for a range of problems comprising of single and multi‐physics steady‐state problems that are applied in one or multiple physical domains. This work provides an example of incorporating code verification as an integral part of LSM development activities.

URLhttp://dx.doi.org/10.1029/2018ms001560
DOI10.1029/2018ms001560
Journal: Journal of Advances in Modeling Earth Systems
Year of Publication: 2019
Volume: 11
Date Published: 04/2019

Current generation Land Surface Models (LSMs) routinely simulate many nonlinear multi‐physics processes. The complexity of future generation LSMs is expected to increase as critical new biophysical and biogeochemical processes are incorporated. Current generation LSMs have several shortcomings including the lack of robust numerical methods to solve discretized equations, monolithic software design that hinders testing of a process representation in isolation from other components, and absence of a flexible coupling framework to solve tightly coupled multi‐physics problems. While the LSMs community vigorously evaluates the accuracy of the conceptual model to represent reality (validation), the accuracy of the numerical implementation of the conceptual model (verification) is seldom examined. Method of Manufactured Solutions (MMS) is a technique for verifying complex codes when analytical solutions are unavailable. In this work, we present a standalone, open source numerical library for solving global terrestrial multi‐physics processes that includes a flexible coupling framework. Robust numerical solution for linear and nonlinear equations is provided via the PETSc library. We verify the numerical library using MMS for a range of problems comprising of single and multi‐physics steady‐state problems that are applied in one or multiple physical domains. This work provides an example of incorporating code verification as an integral part of LSM development activities.

DOI: 10.1029/2018ms001560
Citation:
Bisht, G, and WJ Riley.  2019.  "Development and Verification of a Numerical Library for Solving Global Terrestrial Multi‐Physics Problems."  Journal of Advances in Modeling Earth Systems 11.  https://doi.org/10.1029/2018ms001560.