Geologic Publications for Mount Rainier

Volume loss and surface deflation at Emmons Glacier, Mount Rainier, WA

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Author(s): Jose Jimenez, Claire Todd, Michelle Koutnik

Category: PRESENTATION
Document Type: Poster 265-5
Publisher: Geological Society of America Abstracts with Programs
Published Year: 2024
Volume: 56
Number: 5
Pages:
DOI Identifier: 10.1130/abs/2024AM-405229
ISBN Identifier:
Keywords:

Abstract:
Emmons Glacier is a debris-covered glacier which is situated on the northeastern side of Mount Rainier, WA. The glacier surface is bare ice or surface snow at higher elevations but is debris-covered in the lower elevation ablation zone. Thick debris-cover on glaciers has been known to reduce ice melt but current climate conditions along with a thin debris-cover have led to increased surface melting. Understanding how debris cover influences glacier melt is important for understanding how Mount Rainier glaciers will continue to evolve. This study addresses whether significant elevation change in the lower ablation area of Emmons Glacier corresponds with significant changes in debris-cover morphology; we expect that elevation change is linked to variations in debris cover. We import high-resolution Digital Elevation Models (DEMs) surveyed by the National Park Service in 2021 and a Light Detection and Ranging (LiDAR) topographic survey collected in October 2007/2008 into ArcGIS Pro to investigate glacier change. We can use these data to calculate changes in surface elevation and glacier volume using spatial analysis tools such as DEM differencing, Surface Volume, Geomorphon Landforms, and geostatistical interpolation. To complete DEM differencing, we subtract the 2007/8 surface from the 2021 surface to obtain a difference map which shows us areas where the glacier surface has thickened and thinned. We use the difference map to calculate the volume loss between the surface and a flat reference plane set at zero elevation. Geomorphon analysis classifies landforms elements into 10 common types such as peaks, ridges, valleys, and spurs, using elevation difference analysis around specific points. Applying this analysis to DEMs from 2007/2008 and 2021 shows geomorphological changes over the 13-year period. We also use geostatistical interpolation which estimates thickness of debris cover by analyzing spatial patterns and predictions of our in-situ surface rock debris to glacier ice depth data. Our preliminary results suggest that volume loss and surface deflation correspond with areas of thin debris and geomorphic change. DEM differencing indicates a consistent pattern of ice loss in the lower ablation zone. Geomorphic changes over the last 13 years show significant shifts in debris cover and glacier morphology.

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Suggested Citations:
In Text Citation:
Jimenez and others (2024) or (Jimenez et al., 2024)

References Citation:
Jimenez, J., C. Todd, and M. Koutnik, 2024, Volume loss and surface deflation at Emmons Glacier, Mount Rainier, WA: Poster 265-5, Geological Society of America Abstracts with Programs, Vol. 56, No. 5, doi: 10.1130/abs/2024AM-405229.