Glacier mass changes of lake-terminating Grey and Tyndall glaciers at the southern patagonia icefield derived from geodetic observations and energy and mass balance modeling
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Date
2018-06-19
Journal Title
Journal ISSN
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Publisher
Frontiers Media
Abstract
In this study we demonstrate how energy andmass fluxes vary in space and time for Grey
and Tyndall glaciers at the Southern Patagonia Icefield (SPI). Despite the overall glacier
retreat of most Patagonian glaciers, a recent increase in mass loss has been observed,
but individual glaciers respond differently in terms of spatial and temporal changes.
In this context, the detailed investigation of the effect of mass balance processes on
recent glacier response to climate forcing still needs refinement. We therefore quantify
surface energy-fluxes and climatic mass balance of the two neighboring glaciers, Grey
and Tyndall. The COupled Snow and Ice energy and MAss balance model COSIMA is
applied to assess recent surface energy and climatic mass balance variability with a high
temporal and spatial resolution for a 16-year period between April 2000 and March 2016.
The model is driven by downscaled 6-hourly atmospheric data derived from ERA-Interim
reanalysis and MODIS/Terra Snow Cover and validated against ablation measurements
made in single years. High resolution precipitation fields are determined by using an
analytical orographic precipitation model. Frontal ablation is estimated as residual of
climatic mass balance and geodetic mass balance derived from TanDEM-X/SRTM
between 2000 and 2014. We simulate a positive glacier-wide mean annual climatic
mass balance of +1.02 ± 0.52mw.e. a−1 for Grey Glacier and of +0.68 ± 0.54mw.e.
a−1 for Tyndall Glacier between 2000 and 2014. Climatic mass balance results show
a high year to year variability. Comparing climatic mass balance results with previous
studies underlines the high uncertainty in climatic mass balance modeling with respect
to accumulation on the SPI. Due to the lack of observations accumulation estimates
differ from previous studies based on the methodological approaches. Mean annual
ice loss by frontal ablation is estimated to be 2.07 ± 0.70mw.e. a−1 for Grey Glacier
and 3.26 ± 0.82mw.e. a−1 for Tyndall Glacier between 2000 and 2014. Ice loss by
surface ablation exceeds ice loss by frontal ablation for both glaciers. The overall mass
balance of Grey and Tyndall glaciers are clearly negative with −1.05 ± 0.18mw.e. a−1
and −2.58 ± 0.28mw.e. a−1 respectively.
Description
Keywords
Ciencia, Frontal ablation, Glacier climatic mass balance
Citation
Front. Earth Sci. 6:81