A time series of SAR data for monitoring changes in boundaries of glacier zones on the Antarctic Peninsula

Abstract

Drastic changes have been detected in glacial systems of the Antarctic Peninsula in the last few decades and are well documented in numerous scientific publications. However, the spatial and temporal distribution of glacier changes on the Antarctic Peninsula remains largely restricted to ice fronts. To expand the current monitoring of a few glaciers, unevenly distributed along the peninsula, to a representative set, we developed a method to simplify the detection of boundaries between glacier zones using satellite SAR data. The evolution of glacier zones is greatly influenced by local and regional climatic and meteorological settings. Their variations in response to changes in energy or mass balance are considered as good indicators of climatic changes. In this paper, we describe the results of knowledge-based image analysis algorithms on test areas located at Trinity Peninsula and near Marguerite Bay. In general, the two analyzed areas show different patterns of glacier zone development. The bare-ice zone occurs mainly on glaciers located on the eastern side of Trinity Peninsula. Its upper boundary shows a good correlation with the mean summer air temperature. Finally, the position of the dry-snow line shows different spatial patterns of change in both study areas.

Mapping Radar Glacier Zones and Dry Snow Line in the Antarctic Peninsula Using Sentinel-1 Images

“…As can be seen in Figure 10, σ 0 drops rapidly from −5 dB to −10 dB in the transition, suggesting that the threshold is reasonable within a range. A lower threshold of −8 dB was used by Arigony-Neto et al [8,34]. The result was supported by the higher winter σ 0 with the increased summer melting days derived by SSM/I data (see in Figures 7b and 10).…”

“…Similarly, for the mountainous areas, the very high local incidence angles of the back slopes in the range direction lead to much lower σ 0 (Figure 13c). These places were mistaken for bare ice or dry snow with the elevations below or above 500 m. It is also difficult to map the DSL in glaciers flowing through narrow valleys [34]. We hope that the addition of SAR textural features in future studies can help eliminate these misjudgments.…”

“…Melting signals were found within the areas lower than 1700 m by the SSM/I in this study. Arigony-Neto et al [34] reported that the elevation is higher than 800 in the dry snow radar zone, and lower than 500 m for bare ice in the AP. RGZs can be also characterized by their backscattering characteristics.…”

Spatial and temporal changes in dry-snow line altitude on the Antarctic Peninsula

“…Their variations in response to changes in energy or mass balance are considered as good indicators of climatic changes . In addition, several authors demonstrate the potential of radar remote sensing to identify distinct zonal boundaries within the glaciers (e.g., Fahnestock et al 1993;Forster et al 1996;Braun et al 2000;Rau et al 2000;König et al 2001;Arigony-Neto et al 2007).…”

“…As a consequence, its glacial systems have reacted with drastic changes such as disintegration of ice shelves (Rott et al 1998;Skvarca et al 1999;Rack and Rott 2004), acceleration and thinning of glaciers (De Angelis and Skvarca 2003;Rignot et al 2004;Scambos et al 2004;Pritchard and Vaughan 2007), and retreat of glacier fronts (Rau et al 2004;Cook et al 2005). However, due to the lack of consistent systematic observations in particular of the higher parts of the glacial systems, it is difficult to predict further responses of the AP glaciers to climatic change (Arigony-Neto et al 2007).…”