Surface elevation changes on Lachman Crags ice caps (north-eastern Antarctic Peninsula) since 1979 indicated by DEMs and ICESat data

Abstract

The long-term warming on the Antarctic Peninsula in the second half of the 20th century prompted rapid retreat of glaciers on the peninsula and surrounding islands. Retreat accelerated until the beginning of the new millennium when the regional warming trend significantly decreased. The response of glaciers to the change in temperature trend has been observed around the northern part of the Antarctic Peninsula but the timing of the shift from the surface lowering to mass gain remains unclear. Using historical aerial photographs, DEMs and satellite altimeter data from ICESat, we estimate areal and surface elevation changes of two small ice caps in the northern part of James Ross Island over the last 39 years. The glacierized area on Lachman Crags decreased from 4.337 ± 0.037 to 3.581 ± 0.014 km2 (−17.4%) between 1979 and 2006 and then increased to 3.597 ± 0.047 km2 (0.4%) until 2016. Surface lowering observed on ice caps after 1979 continued at least until 2008 as indicated by the ICESat data. The change from the lowering trend to increase in glacier surface elevation probably occurred after the ablation season 2008/09, which ranks among the warmest summers in the north-eastern Antarctic Peninsula since the mid-20th century.

Keywords

• Antarctic glaciology
• climate change
• ice cap
• ice thickness measurements
• laser altimetry