Heterogeneous spatial and temporal pattern of surface elevation change and mass balance of the Patagonian ice fields between 2000 and 2016

Abdel Jaber, Wael; Rott, Helmut; Floricioiu, Dana; Wuite, Jan; Miranda, Nuno

The northern and southern Patagonian ice fields (NPI and SPI) have been subject to accelerated retreat during the last decades, with considerable variability in magnitude and timing among individual glaciers. We derive spatially detailed maps of surface elevation change (SEC) of NPI and SPI from bistatic synthetic aperture radar (SAR) interferometry data of the Shuttle Radar Topography Mission (SRTM) and TerraSAR-X add-on for Digital Elevation Measurements (TanDEM-X) for two epochs, 2000–2012 and 2012–2016, and provide data on changes in surface elevation and ice volume for the individual glaciers and the ice fields at large. We apply advanced TanDEM-X processing techniques allowing us to cover 90 % and 95 % of the area of NPI and 97 % and 98 % of SPI for the two epochs, respectively. Particular attention is paid to precisely co-registering the digital elevation models (DEMs), accounting for possible effects of radar signal penetration through backscatter analysis and correcting for seasonality biases in case of deviations in repeat DEM coverage from full annual time spans. The results show a different temporal trend between the two ice fields and reveal a heterogeneous spatial pattern of SEC and mass balance caused by different sensitivities with respect to direct climatic forcing and ice flow dynamics of individual glaciers. The estimated volume change rates for NPI are inline-formula M1inlinescrollmathml - normal 4.26 ± normal 0.20 64pt10ptsvg-formulamathimgb89828f9a77603a2d41ef60c7baad2d2 tc-13-2511-2019-ie00001.svg64pt10pttc-13-2511-2019-ie00001.png  kminline-formula3 ainline-formula−1 for epoch 1 and inline-formula M4inlinescrollmathml - normal 5.60 ± normal 0.74 64pt10ptsvg-formulamathimg6107849c234e9d59f9331ac093ed7038 tc-13-2511-2019-ie00002.svg64pt10pttc-13-2511-2019-ie00002.png  kminline-formula3 ainline-formula−1 for epoch 2, while for SPI these are inline-formula M7inlinescrollmathml - normal 14.87 ± normal 0.52 70pt10ptsvg-formulamathimgc40fe4cc7ac52c795dc00b6c7053c0cd tc-13-2511-2019-ie00003.svg70pt10pttc-13-2511-2019-ie00003.png  kminline-formula3 ainline-formula−1 for epoch 1 and inline-formula M10inlinescrollmathml - normal 11.86 ± normal 1.99 70pt10ptsvg-formulamathimgba6365d233129f58fab56edcfdb48f7e tc-13-2511-2019-ie00004.svg70pt10pttc-13-2511-2019-ie00004.png  kminline-formula3 ainline-formula−1 for epoch 2. This corresponds for both ice fields to an eustatic sea level rise of inline-formula0.048±0.002 mm ainline-formula−1 for epoch 1 and inline-formula0.043±0.005 mm ainline-formula−1 for epoch 2. On SPI the spatial pattern of surface elevation change is more complex than on NPI and the temporal trend is less uniform. On terminus sections of the main calving glaciers of SPI, temporal variations in flow velocities are a main factor for differences in SEC between the two epochs. Striking differences are observed even on adjoining glaciers, such as Upsala Glacier, with decreasing mass losses associated with slowdown of flow velocity, contrasting with acceleration and increase in mass losses on Viedma Glacier.



Abdel Jaber, Wael / Rott, Helmut / Floricioiu, Dana / et al: Heterogeneous spatial and temporal pattern of surface elevation change and mass balance of the Patagonian ice fields between 2000 and 2016. 2019. Copernicus Publications.


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