| This research examines the influence of climatic variations, soil properties and site difference on active layer temperature dynamics and active layer depths along the Western Antarctic Peninsula (WAP). Over the last 50 years air temperatures along the WAP have risen by nearly 2.5ºC, a rate nearly six times the global average. This rapid regional warming has had a significant effect on active layer thicknesses along the WAP; however, there are only a few monitoring sites along the WAP to observe the effects of these changes on active layer thicknesses. Active layer predictive equations and models, validated in the northern hemisphere, can be successfully applied to sites in the WAP. The impact of several geomorphic and climatic factors were measured at two mid-latitude locations along the WAP, while the effect of location differences were compared among five active layer monitoring sites along a latitudinal gradient. Soils with higher water contents had faster thermal propagation rates but deeper active layers. Solar radiation and air temperatures had the most significant climatic effect on active layer temperature dynamics. Snow cover was under 0.6 m for two out of the three monitored years, which was thick enough to create a physical barrier but not a thermal barrier. Average active layers depths on the northern South Orkney and South Shetland Islands was between 1.6 and 5.0 m, while thicknesses at the mid-latitude Cierva Point and Amsler Island sites was between 6.8 and 14.0 m and the southern Rothera Point had thinner average active layer thicknesses of 1.2 m. Elevation differences accounted for at least 4.3 m of active layer thickness variations among sites, while other site variations had minimal impact on active layer depths. Thicker mid-latitude active layers mirrored warmer average air temperatures measured at the same locations, suggesting a region of intensified warming within the WAP. An expanded network of active layer monitoring stations will be necessary to better understand the cause and extent of this mid latitude warming. |
