Ocean-glacier interaction on the large regional scale
Glaciers are important regulators of water availability in many regions of the world and their retreat can lead to increased geohazards. Glacier melt has contributed significantly to sea-level rise in the past and has become the biggest single source of observed sea-level rise since 1900, even if th...
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| Other Authors: | , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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Universität Bremen
2020
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| Online Access: | https://media.suub.uni-bremen.de/handle/elib/4637 https://doi.org/10.26092/elib/434 https://nbn-resolving.org/urn:nbn:de:gbv:46-elib46378 |
| Summary: | Glaciers are important regulators of water availability in many regions of the world and their retreat can lead to increased geohazards. Glacier melt has contributed significantly to sea-level rise in the past and has become the biggest single source of observed sea-level rise since 1900, even if the ice mass stored in glaciers is small compared to the Greenland and Antarctic ice sheets (<1%). Glacier melt has and will continue to be a major source of sea-level rise in the 21st century. Therefore, it is a pressing task to improve the knowledge of how glaciers change when subjected to climate change, both natural and anthropogenic. About 30% of the glaciers on earth terminate in the ocean and frontal ablation (mass loss by calving and frontal melting) is a major component of the mass budget of tidewater glaciers, strongly affecting their dynamics. Most global scale ice volume estimates to date still suffer from considerable uncertainties related to i) the implemented frontal ablation parameterization or ii) not accounting for frontal ablation at all in the glacier model. To improve estimates of the ice thickness distribution of tidewater glaciers, it is thus important to identify and test low-cost and robust parameterizations of this process. By implementing such parameterization into the ice-thickness estimation module of the Open Global Glacier Model (OGGM v1.1.2), this thesis conducts a first assessment of the impact of accounting for frontal ablation on the estimate of ice stored in glaciers located in Alaska and Greenland. OGGM is the first globally applicable, open source, community-driven model for consistently simulating past and future global scale glacier change. It's ice thickness inversion scheme relies on a mass-conservation approach, this thesis found that if frontal ablation is neglected from the mass balance budget, the model systematically underestimated the mass turnover, and therefore the thickness and volume of tidewater glaciers. This underestimation can amount to up to 19% on a regional ... |
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