Analytic and modeled results indicate that the depth of a soil model in order to properly reproduce permafrost behavior on a range of timescales should not be less than 170m. Many current-generation climate models have land components that are too shallow (3–10 m). Shallow models alter the terrestrial heat storage and distribution of temperatures in the subsurface and therefore are inaccurate because do not properly reproduce the timescales and amplitudes of the simulated warming trend.
This study bridges the gap between analytical and simulation-based estimates of the subsurface thermodynamic state by adapting the classic analytical framework to mimic long-term anthropogenic warming.
The analysis shows that a land-model depth of at least 170 m is recommended for a proper simulation of the post-1850 ground climate, which differs up to 30% from the estimate of the classic approach. Compared to previous studies, this provides an accurate estimate of the required land model depth for long-term climate-change simulations and indicates the relative bias in insufficiently deep land models.