Abstract. 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 -4.26±0.20 km3 a−1
for epoch 1 and -5.60±0.74 km3 a−1
for epoch 2, while for SPI these are -14.87±0.52 km3 a−1
for epoch 1 and -11.86±1.99 km3 a−1
for epoch 2. This corresponds for both ice fields to an eustatic sea
level rise of 0.048±0.002 mm a−1 for
epoch 1 and 0.043±0.005 mm a−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.
Solid-Gas Reaction during Sintering of Si3N4 Ceramics. (Part 3). Mass Losses in a Carbon Heater Furnace.
