Elevation and Mass Changes of the Southern Patagonia Icefield Derived from TanDEM-X and SRTM Data

Abstract

Abstract:The contribution to sea level rise from Patagonian icefields is one of the largest mass losses outside the large ice sheets of Antarctica and Greenland. However, only a few studies have provided large-scale assessments in a spatially detailed way to address the reaction of individual glaciers in Patagonia and hence to better understand and explain the underlying processes. In this work, we use repeat radar interferometric measurements of the German TerraSAR-X-Add-on for Digital Elevation Measurements (TanDEM-X) satellite constellation between 2011/12 and 2016 together with the digital elevation model from the Shuttle Radar Topography Mission (SRTM) in 2000 in order to derive surface elevation and mass changes of the Southern Patagonia Icefield (SPI). Our results reveal a mass loss rate of −11.84 ± 3.3 Gt·a −1 (corresponding to 0.033 ± 0.009 mm·a −1 sea level rise) for an area of 12573 km 2 in the period 2000-2015/16. This equals a specific glacier mass balance of −0.941 ± 0.19 m w.e.·a −1 for the whole SPI. These values are comparable with previous estimates since the 1970s, but a magnitude larger than mass change rates reported since the Little Ice Age. The spatial pattern reveals that not all glaciers respond similarly to changes and that various factors need to be considered in order to explain the observed changes. Our multi-temporal coverage of the southern part of the SPI (south of 50.3 • S) shows that the mean elevation change rates do not vary significantly over time below the equilibrium line. However, we see indications for more positive mass balances due to possible precipitation increase in 2014 and 2015. We conclude that bi-static radar interferometry is a suitable tool to accurately measure glacier volume and mass changes in frequently cloudy regions. We recommend regular repeat TanDEM-X acquisitions to be scheduled for the maximum summer melt extent in order to minimize the effects of radar signal penetration and to increase product quality.

Air Temperature Characteristics, Distribution, and Impact on Modeled Ablation for the South Patagonia Icefield

“…Patagonia (40-55°S) contains the largest glacierized area in South America, but recent evidence shows that most of these glaciers are shrinking rapidly (Davies & Glasser, 2012;Foresta et al, 2018;Malz et al, 2018;Meier et al, 2018;White & Copland, 2015). This deglaciation is primarily a matter of concern for sea level rise (Foresta et al, 2018;Gardner et al, 2013;Rignot et al, 2003;Willis et al, 2012).…”

Underwater Ice Terrace Observed at the Front of Glaciar Grey, a Freshwater Calving Glacier in Patagonia

“…Calving glaciers change more rapidly than land-terminating glaciers (e.g., Post et al, 2011) and thus play a central role in global sea level rise (e.g., Burgess et al, 2013;Dussaillant et al, 2018;Howat & Eddy, 2011;Malz et al, 2018;Nuth et al, 2013). Among the calving glaciers, those terminating in freshwater have drawn less attention as compared to tidewater glaciers.…”

“…Most of these freshwater calving glaciers are receding over the last several decades (e.g., Sakakibara & Sugiyama, 2014;White & Copland, 2015). Some of the glaciers are rapidly retreating and thinning, affecting recent mass loss in Patagonia (e.g., Dussaillant et al, 2018;Malz et al, 2018). Studies in Alaska have shown that some of the freshwater calving glaciers are retreating more rapidly than tidewater glaciers in the region (Larsen et al, 2015).…”

Detailed quantification of glacier elevation and mass changes in South Georgia

“…Shepherd et al 2018, Rignot et al 2019, the Antarctic Peninsula (Rott et al 2014, Rott et al 2018 and Patagonia (e.g. Malz et al 2018, less is known about the glaciers located on the sub-Antarctic islands and the potential impacts of atmospheric warming on their retreat during the 20th and 21st centuries.…”

“…The geodetic approach does not resolve seasonal variations but has been widely used to estimate long-term glacier mass balances, especially in remote regions (e.g. Malz et al 2018 where meteorological and logistical conditions limit continuous glacier monitoring, such as at South Georgia. Therefore, we derive surface elevation change rates using interferometric synthetic aperture radar (InSAR) resulting in the calculation of island-wide glacier mass balances.…”