Glacier Response to Climate Change: Modeling the Effects of Weather and Debris-Cover
Glaciers change length in response to fluctuations in climate. In addition, atmospheric and geomorphic processes modulate glacier response to climate change. These factors must be explored in detail to understand glacier response. I engage two factors modulating glacier response: 1) the effect of ye...
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ftunicolboulder:oai:scholar.colorado.edu:geol_gradetds-1094 2023-05-15T16:20:22+02:00 Glacier Response to Climate Change: Modeling the Effects of Weather and Debris-Cover Anderson, Leif S. 2014-01-01T08:00:00Z application/pdf https://scholar.colorado.edu/geol_gradetds/90 https://scholar.colorado.edu/cgi/viewcontent.cgi?article=1094&context=geol_gradetds unknown CU Scholar https://scholar.colorado.edu/geol_gradetds/90 https://scholar.colorado.edu/cgi/viewcontent.cgi?article=1094&context=geol_gradetds Geological Sciences Graduate Theses & Dissertations Climate change Debris cover Glacier Modeling Glaciers Interannual climate variability Numerical Modeling Climate Geomorphology Glaciology text 2014 ftunicolboulder 2018-10-07T08:54:53Z Glaciers change length in response to fluctuations in climate. In addition, atmospheric and geomorphic processes modulate glacier response to climate change. These factors must be explored in detail to understand glacier response. I engage two factors modulating glacier response: 1) the effect of year-to-year weather variability on glacier length and 2) the effect of debris cover on glacier dynamics. I use case studies from the Last Glacial Maximum (LGM) in Colorado in addition to modern glaciers in the Nepalese Himalaya and Alaska to address these issues. The effect of interannual variability on the moraine record Multi-decadal, kilometer-scale fluctuations in glacier length occur in response to stochastic, year-to-year variability in mass balance. I address the effect of weather variability on our interpretation of the moraine record using glacier models in the Colorado Front Range during the LGM. My analyses suggest that (1) glacial standstills longer than 50 years were unlikely; (2) mean glacier lengths are ~10%-15% up-valley from maximum glacier lengths; and (3) individual LGM terminal moraines were formed by a combination of a climate change and interannual variability-forced advances. Numerical modeling of debris-covered glaciers Debris cover can significantly affect the length and dynamics of valley glaciers. I developed a 2D vertical plane long-valley numerical glacier model with which we explore the feedbacks between debris and ice dynamics. Debris input to the glacier in the accumulation zone emerges in the ablation zone, and is then advected along the glacier surface, damping melt rate. Debris cover reduces ice surface slopes, ice thickness gradients, ice discharge gradients, and englacial velocities in the ablation zone. Ice cliffs on debris-covered glaciers Debris cover suppresses ice melt on glaciers. However, the retreat of debris-free ice cliffs within otherwise debris-covered glaciers counters the insulating effects of debris. I provide a theoretical framework for the production and removal of ice cliffs and glacier surface topography on the Kennicott Glacier, Wrangell Mountains, Alaska. Mean debris thickness exerts primary control on glacier surface relief and ice cliff concentration. Approximately 30% of net mass loss from the study area is due to the retreat of ice cliffs. Text glacier glaciers Alaska University of Colorado, Boulder: CU Scholar Long Valley ENVELOPE(-147.800,-147.800,-86.217,-86.217) |
institution |
Open Polar |
collection |
University of Colorado, Boulder: CU Scholar |
op_collection_id |
ftunicolboulder |
language |
unknown |
topic |
Climate change Debris cover Glacier Modeling Glaciers Interannual climate variability Numerical Modeling Climate Geomorphology Glaciology |
spellingShingle |
Climate change Debris cover Glacier Modeling Glaciers Interannual climate variability Numerical Modeling Climate Geomorphology Glaciology Anderson, Leif S. Glacier Response to Climate Change: Modeling the Effects of Weather and Debris-Cover |
topic_facet |
Climate change Debris cover Glacier Modeling Glaciers Interannual climate variability Numerical Modeling Climate Geomorphology Glaciology |
description |
Glaciers change length in response to fluctuations in climate. In addition, atmospheric and geomorphic processes modulate glacier response to climate change. These factors must be explored in detail to understand glacier response. I engage two factors modulating glacier response: 1) the effect of year-to-year weather variability on glacier length and 2) the effect of debris cover on glacier dynamics. I use case studies from the Last Glacial Maximum (LGM) in Colorado in addition to modern glaciers in the Nepalese Himalaya and Alaska to address these issues. The effect of interannual variability on the moraine record Multi-decadal, kilometer-scale fluctuations in glacier length occur in response to stochastic, year-to-year variability in mass balance. I address the effect of weather variability on our interpretation of the moraine record using glacier models in the Colorado Front Range during the LGM. My analyses suggest that (1) glacial standstills longer than 50 years were unlikely; (2) mean glacier lengths are ~10%-15% up-valley from maximum glacier lengths; and (3) individual LGM terminal moraines were formed by a combination of a climate change and interannual variability-forced advances. Numerical modeling of debris-covered glaciers Debris cover can significantly affect the length and dynamics of valley glaciers. I developed a 2D vertical plane long-valley numerical glacier model with which we explore the feedbacks between debris and ice dynamics. Debris input to the glacier in the accumulation zone emerges in the ablation zone, and is then advected along the glacier surface, damping melt rate. Debris cover reduces ice surface slopes, ice thickness gradients, ice discharge gradients, and englacial velocities in the ablation zone. Ice cliffs on debris-covered glaciers Debris cover suppresses ice melt on glaciers. However, the retreat of debris-free ice cliffs within otherwise debris-covered glaciers counters the insulating effects of debris. I provide a theoretical framework for the production and removal of ice cliffs and glacier surface topography on the Kennicott Glacier, Wrangell Mountains, Alaska. Mean debris thickness exerts primary control on glacier surface relief and ice cliff concentration. Approximately 30% of net mass loss from the study area is due to the retreat of ice cliffs. |
format |
Text |
author |
Anderson, Leif S. |
author_facet |
Anderson, Leif S. |
author_sort |
Anderson, Leif S. |
title |
Glacier Response to Climate Change: Modeling the Effects of Weather and Debris-Cover |
title_short |
Glacier Response to Climate Change: Modeling the Effects of Weather and Debris-Cover |
title_full |
Glacier Response to Climate Change: Modeling the Effects of Weather and Debris-Cover |
title_fullStr |
Glacier Response to Climate Change: Modeling the Effects of Weather and Debris-Cover |
title_full_unstemmed |
Glacier Response to Climate Change: Modeling the Effects of Weather and Debris-Cover |
title_sort |
glacier response to climate change: modeling the effects of weather and debris-cover |
publisher |
CU Scholar |
publishDate |
2014 |
url |
https://scholar.colorado.edu/geol_gradetds/90 https://scholar.colorado.edu/cgi/viewcontent.cgi?article=1094&context=geol_gradetds |
long_lat |
ENVELOPE(-147.800,-147.800,-86.217,-86.217) |
geographic |
Long Valley |
geographic_facet |
Long Valley |
genre |
glacier glaciers Alaska |
genre_facet |
glacier glaciers Alaska |
op_source |
Geological Sciences Graduate Theses & Dissertations |
op_relation |
https://scholar.colorado.edu/geol_gradetds/90 https://scholar.colorado.edu/cgi/viewcontent.cgi?article=1094&context=geol_gradetds |
_version_ |
1766008282810417152 |