NGEE Arctic
Next-Generation Ecosystem Experiments
Advancing the predictive power of Earth system models through understanding
of the structure and function of Arctic terrestrial ecosystems
Model-data Comparison Highlights Overlooked Processes in Models of Soil Moisture and Hydrology
Model-data Comparison Highlights Overlooked Processes in Models of Soil Moisture and Hydrology
August 24th, 2020
Most models project a long-term drying of the surface soil for the permafrost region despite increases in the net air–surface water flux.
The Objective:
- Investigate and compare soil moisture projections for eight land models with permafrost processes and highlight the causes and impacts of ground subsidence on soil moisture projections.
New Science:
- Models commonly used to represent carbon loss from tundra ecosystems were analyzed, for the first time, to identify assumptions underlying soil moisture calculations.
- Thawing of permafrost can lead to an increase in the hydraulic conductivity of the soil column, thereby enhancing redistribution of water in the soil column.
The Impact:
- Large discrepancies in projections remain as the current generation of models substantially differ in how they represent soil thermal processes and ground subsidence as a result of permafrost thaw.
- Models must be further evaluated to further quantify the uncertainty associated with these deficiencies.
Schematic of soil water table with and without ground subsidence