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

Zbyněk Engel,Jan Kropáček,Jana Smolíková

doi:10.1017/jog.2019.19

Abstract

ABSTRACTThe 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.

Highlights

The Antarctic Peninsula (AP) and the sub-Antarctic islands around its northern tip represent a large glacierized area with numerous glaciers and ice caps outside the Antarctic ice sheet
In summer 1999–2000, mass-balance measurements started on Bahía del Diablo Glacier on Vega Island on the eastern side of the AP (Fig. 1), with data having been reported to the World Glacier Monitoring Service (WGMS)
For the calculations of the first uncertainty component, we considered a conservative estimate of vertical resolution

Summary

Introduction

The Antarctic Peninsula (AP) and the sub-Antarctic islands around its northern tip represent a large glacierized area with numerous glaciers and ice caps outside the Antarctic ice sheet. Most of these glaciers are considered to be in retreat and losing mass, but available glaciological observations are sparse and regionally biased. Area, volume or mass were determined only for fraction of the local glaciers, and the AP is ranked among poorly sampled regions (Mernild and others, 2013; Zemp and others, 2015). Since the beginning of 21st century, in situ glaciological monitoring programmes have been initiated to determine the mass balance of small ice caps and glaciers around the AP.

Results

Discussion

Conclusion