Submitted to: Seasonally Frozen Soils Symposium
Publication Type: Proceedings
Publication Acceptance Date: June 12, 1997
Publication Date: N/A
Interpretive Summary: Frost depth governs how deep water pipes should be buried, the ability to forecast stream flow, the potential for river flooding, and the axle load of vehicles which can be driven across wet soils. We compared the predictions of three frost models to simulate frost depth and soil temperatures under a range of climate and soil conditions. The best prediction of frost depth is achieved with the most complex models used in our study. The most simplistic model grossly overestimated frost depth, yet this model is used to forecast the depth of frozen soil as an aid in assessing the potential for soil erosion. Therefore, agencies such as NRCS or NWS which have interest in estimating frost depths must use caution when utilizing simplistic models. These agencies should consider using a more rigorous approach to predicting frost depths.
Technical Abstract: Three existing soil models capable of simulating soil frost depths and temperatures were evaluated for their ability to predict the depth and timing of soil frost at sites in northern and Midwestern North America. The evaluation was carried out by comparing model simulation results to observed field data. The data used in the comparisons came from two sites, one near Delta Junction, AK, characterized by a cryaquept with grass cover, and the other near Morris, MN characterized by a haploboroll with corn stubble. Two of the models that use a finite difference solution to heat flow in the soil profile both predicted frost depth with reasonable accuracy, at least when the simulated snow depth closely matched the recorded snow depth. The third model balances heat fluxes and vastly over predicted frost depths. The results illustrate the importance of snow cover in controlling soil frost as well as the difficulty in accurately simulating snow cover and soil frost.