2019 CSDMS meeting-097
The CryoGrid permafrost models: examples of applications
Permafrost thaw is of growing concern due to its potential to weaken slope stability and influence the magnitude and frequency of rapid mass movements in an area. Therefore, modelling of permafrost distribution and dynamics is needed for mountain areas, where such events happened or might happen. For instance in Iceland, permafrost thaw has been recently recognized as a new factor influencing landslide triggering, whereas the instability and slow movement of the unstable rock slope Mannen in southwestern Norway might be connected to permafrost conditions.
CryoGrid is a suite of permafrost models for solving different problems related to permafrost processes. This presentation will show examples of application of the two model schemes, the one-dimensional model CryoGrid 2 (Westermann et al., 2013) and the two-dimensional model CryoGrid 2D (Myhra et al., 2017). Both models solve the transient heat diffusion equation that additionally accounts for the latent heat effects due to ground freezing or thawing. The CryoGrid 2 model is forced with time series of air/ground surface temperature and snow depth data, whereas the CryoGrid 2D model is forced with ground surface temperature.
We applied CryoGrid 2 to the regional modelling of permafrost dynamics in Iceland for the last six decades. To account for snow redistribution, we ran the model for three scenarios of the snow depth, having a large impact on the modelled permafrost distribution.
CryoGrid 2D was employed to model ground temperature in the Mannen rock slope since the 1860s. Our preliminary results show that permafrost can occur in the Mannen slope in areas with considerably reduced snow depth, i.e. under steep parts of the slope.
Myhra, K. S., Westermann, S., & Etzelmüller, B. (2017). Modelled distribution and temporal evolution of permafrost in steep rock walls along a latitudinal transect in Norway by CryoGrid 2D. Permafrost and Periglacial Processes, 28(1), 172-182. DOI: 10.1002/ppp.1884
Westermann, S., Schuler, T., Gisnås, K., & Etzelmüller, B. (2013). Transient thermal modeling of permafrost conditions in Southern Norway. The Cryosphere, 7(2), 719-739. DOI: 10.5194/tc-7-719-2013