Analytical–statistical models (ASMs) for mean annual permafrost table temperature and active-layer thickness

Mean annual permafrost table temperature (MAPT) and active-layer thickness (ALT) are key variables for assessing the thermal regimes of permafrost and active layer and their responses to climate changes. Models for estimating MAPT and ALT have typically been forced by air or ground temperatures and some ground physical properties. While temperature measurements are relatively widely available and reliable, ground physical properties are frequently unavailable or unrepresentative and therefore need to be estimated, which introduces uncertainties into model outputs.

Hence, we devised two simple analytical−statistical models (ASMs) for estimating MAPT and ALT, which are driven solely by pairwise combinations of freezing and thawing indices in the active layer. We tested the models at the total of 55 sites in the Earth's major permafrost regions comprising five different ground surface covers and four permafrost zones where the models showed the total mean errors of less than 0.05 °C for MAPT and 9 % for ALT. Besides, the models can also be used to establish typical values of some ground physical parameters for MAPT and ALT estimates. We believe that ASMs can find useful applications in permafrost and active-layer modelling under a wide range of climates, ground surface covers, and ground physical conditions.

 

Acknowledgement

The research was funded by the Czech Science Foundation (project numbers GM22-28659M and GA25-18272S) and by the Ministry of Education, Youth and Sports (project number LL2505).