The evolution of a near-surface ground thermal regime and modeled active-layer thickness on James Ross Island, Eastern Antarctic Peninsula, in 2006-2016
Abstract
Thermal regime and thickness of the active layer respond rapidly to climate variations, and thus they are important measures of cryosphere changes in polar environments. We monitored air temperature and ground temperature at a depth of 5 cm and modeled active-layer thickness using the Stefan and Kudryavtsev models at the Abernethy Flats site, James Ross Island, Eastern Antarctic Peninsula, in the period March 2006 to February 2016.
The decadal average of air and ground temperature was -7.3 and -6.1°C, respectively, and the average modeled active-layer thickness reached 60 cm. Mean annual air temperature increased by 0.10°C y-1 over the study period, while mean annual ground temperature showed the opposite tendency of -0.05°C y-1.
The cooling took place mainly in summer and caused thawing season shortening and active-layer thinning of 1.6 cm y-1. However, these trends need to be taken carefully because all were non-significant at p < 0.05.
The Stefan and Kudryavtsev models reproduced the active-layer thickness with mean absolute errors of 2.6 cm (5.0%) and 3.4 cm (5.9%), respectively, which is better than in most previous studies, making them promising tools for active-layer modeling over Antarctica.