The application of simple models to predict active layer thickness on James Ross Island in 2006-2015
Abstract
Active layer thickness reflects very well both warm periods enhancing its thickening and colder periods causing its thinning. Such variability has been observed over the last few decades in Antarctic Peninsula region where significant active layer thawing and degradation of permafrost caused by gradual climate warming were followed by thinning of active layer thickness due to climate cooling in the last decade.
Among other approaches, such as ground temperature measurements, manual probing or geophysical surveying, thermal modelling techniques represent very useful tool to assess the active layer thickness variability. These methods have been widely used in Arctic regions since 1990s.
On the other hand, their application in Antarctica has thus far been very limited. In this contribution, we present the first results of Stefan and Kudryavtsev models, which were applied to predict the annual active layer thickness in summer seasons 2006/07 to 2014/15 on James Ross Island, eastern Antarctic Peninsula.
Average modelled active layer thickness varied between 60 cm (Kudryavtsev model) and 62 cm (Stefan model) in period 2006/07 to 2014/15. Both models predicted active layer thinning of -1.3 cm.year-1 (Stefan model) to -2.3 cm.year-1 (Kudryavtsev model), which is in contradiction to the general trend of active layer thickness in the Antarctic Peninsula region in the last decade.
The maximum predicted active layer thickness reached 75 cm (Stefan model) and 83 cm (Kudryavtsev model) in 2008/09, while the minimum active layer thickness was predicted to 36 cm in 2009/10 by both models. The modelling results showed their suitability for active layer thickness predictions in Antarctica, since their accuracy ranged in the order of first centimeters.
We modelled thinning of active layer thickness over the study period, which was mainly related to variability of summer air temperature.