A numerical study of process complexity in permafrost dominated regions

authored by: Radhakrishna Bangalore Lakshmiprasad, Fan Zhang, Ethan T. Coon, Thomas Graf
Abstract: Numerical modeling of permafrost dynamics requires adequate representation of atmospheric and surface processes, a reasonable parameter estimation strategy, and site-specific model development. The three main research objectives of the study are: (i) to propose a novel methodology that determines the required level of surface process complexity of permafrost models by conducting parameter sensitivity and calibration, (ii) to design and compare three numerical models of increasing surface process complexity, and (iii) to calibrate and validate the numerical models at the Yakou catchment on the Qinghai-Tibet Plateau as an exemplary study site. The calibration was carried out by coupling the Advanced Terrestrial Simulator (numerical model) and PEST (calibration tool). Simulation results showed that (i) A simple numerical model that considers only subsurface processes can simulate active layer development with the same accuracy as other more complex models that include surface processes. (ii) Peat and mineral soil layer permeability, Van Genuchten alpha, and porosity are highly sensitive. (iii) Liquid precipitation aids in increasing the rate of permafrost degradation. (iv) Deposition of snow insulated the subsurface during the thaw initiation period. We have developed and released an integrated code that couples the numerical software ATS to the calibration software PEST. The numerical model can be further used to determine the impacts of climate change on permafrost degradation.
Organisation(s): Institute of Fluid Mechanics and Environmental Physics in Civil Engineering
External Organisation(s): Chinese Academy of Sciences (CAS)
Oak Ridge National Laboratory
Type: Article
Journal: Cold Regions Science and Technology
Volume: 231
ISSN: 0165-232X
Publication date: 03.2025
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Geotechnical Engineering and Engineering Geology, General Earth and Planetary Sciences
Sustainable Development Goals: SDG 3 - Good Health and Well-being, SDG 13 - Climate Action
Electronic version(s): https://doi.org/10.1016/j.coldregions.2024.104399 (Access: Open)