Near-Term Global Glacier Mass Balance Modelling

authored by: Larissa Nora van der Laan
supervised by: Kristian Förster
Abstract: Glaciers play a vital role in regulating the earth's climate and have societal as well as scientific significance. Acting as cultural heritage, ecosystem components, water storage and contributors to sea level rise, they have both direct and indirect impact on humanity. Vanishing glaciers are also some of the most readily available illustrations of climate change and emphasize the reality and urgency of climate change and its impact. There are approximately 216,000 glaciers globally, which are monitored and catalogued, providing large data sets for research in glaciology, hydrology, and climatology. Their mass changes provide valuable information about the state of the global climate and raise concerns about the potential impacts of climate change on freshwater resources and ecosystems. With their capacity for water storage, glacier mass change can affect and cause hydroclimatic events, including droughts and floods, and well as water availability: an essential aspect of the overall water cycle. In order for communities to increase their resilience to these changes, there is a need for reliable predictions of the magnitude and timing of glacier mass loss on seasonal to decadal time scales, referred to as near-term. The aim of this study is to improve our understanding of glacier modelling on this time scale and analyze the utility of seasonal to decadal scale forcing in a global glacier model. Through the application of a scenario-neutral approach, the concept of glacier sensitivity is explored, while providing a framework in which to analyze and better understand glacier response to changes in temperature and precipitation on various scales. Next, the potential of seasonal forecasting with Open Global Glacier Model (OGGM) is assessed. The glacier model is forced with a multi-model ensemble of seasonal forecasts. The results are interpreted in terms of predictive skill: whether the upcoming season would be above or below a certain mass balance threshold. This type of coarse information could provide valuable early warning information for water resource management, but is not attained with the current approach. The final component of this study is the application of decadal (retrospective) forecasts in mass balance and runoff modelling with OGGM. The results with this method show similar or better skill when compared to a simple persistence approach and to the current state of the art in predicting glacier evolution for the 21st century, climate projections. Forcing OGGM with these type of initialized forecasts could complement centennial scale glacier and climate modelling, providing information on a time scale that is particularly relevant for water resource management.
Organisation(s): Institute of Hydrology and Water Resources Management
Type: Doctoral thesis
No. of pages: 139
Publication date: 2023
Publication status: Published
Sustainable Development Goals: SDG 6 - Clean Water and Sanitation, SDG 13 - Climate Action, SDG 14 - Life Below Water, SDG 15 - Life on Land
Electronic version(s): https://doi.org/10.15488/14171 (Access: Open)