Mass balance of Icelandic glaciers in variable climate

• Main Author: Belart, Joaquín M. C.
• Other Authors: Eyjólfur Magnússon og Etienne Berthier, Jarðvísindadeild (HÍ), Faculty of Earth Sciences (UI), Laboratoire d'Etudes en Géophysique et Océanographie Spatiale, Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland, University of Toulouse 3 - Paul Sabatier
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Iceland, School of Engineering and Natural Sciences, Faculty of Earth Sciences 2018
• Subjects: Remote sensing; Mass balance; Glacier-climate relationship; Fjarkönnun; Jöklarannsóknir; Úrkoma; Hitamælingar; Veðurfar; Jarðeðlisfræði; Doktorsritgerðir; Drangajökull; Eyjafjallajökull; glacier; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/923

The mass balance of a glacier is strongly connected to climate. At high latitudes, mass balance is typically controlled by snow accumulation during the winter and the glacier ablation during the summer. In Iceland, direct mass balance observations have been mostly focused on the three largest ice caps (~600 to ~8000 km2), measured in situ for the last 25 years. There are, however, glaciers and ice caps distributed over all quarters of the country that lack mass balance observations. Remote sensing data with the capability to retrieve the glacier surface geometry through Digital Elevation Models (DEMs) are valuable tools to measure mass balance using the geodetic method. For a typical Icelandic glacier (with an area between 1 km2 and hundreds of km2), this can be optimally achieved from optical stereoscopic imagery, emplaced in airborne or spaceborne sensors, and from airborne lidar. This thesis focuses on remote sensing techniques to accurately measure geodetic mass balance from seasonal to decadal time spans and the relationship of mass balance to climate. As an example of seasonal mass balance, the winter mass balance of Drangajökull was measured from satellite sub-meter stereo images at the beginning, middle and end of the 2014–2015 winter using data from the Pléiades and WorldView-2 satellites. The results were complemented with in situ snow density measurements and validated with snow thickness measurements. The study concludes that images from the sensors mentioned above may often be used to monitor seasonal mass balance without tedious field logistics. A vast archive of aerial photographs exists for Iceland extending back to 1945. Since then, most glaciers were surveyed every 5 to 20 years. In addition, a wealth of modern satellite stereo images is available since the early 2000s as well as airborne lidar data in 2008–2013. This creates a unique dataset to construct a 70-year time series of geodetic mass balances. Eyjafjallajökull (~70 km2) was used to develop semi-automated processing chains based on ...