The PhD defence and trial lecture are fully digital and streamed using Zoom. The host of the session will moderate the technicalities while the chair of the defence will moderate the disputation.
Trial lecture
Ice-ocean interactions: processes controlling tidewater glaciers, marine ice sheets and ice shelves
Conferral summary
Brehydrologi beskriver vann i og rundt isbreer. Vannet er viktig for brebevegelser, for havnivåstigning, geofarer, vannkraft, og som drikkevannskilde. Kunnskapen om brehydrologi er likevel begrenset, fordi den er vanskelig å måle. I dette doktorgradsarbeidet utvikles det derfor en ny målemetode ved hjelp av «Driftere» for å måle brehydrologien. Studien omfatter også temperaturmålinger av permafrost under isbreer, og videre diskuteres den effekten klimaendringer har på Svalbards brehydrologi.
Main research findings
Popular scientific article about Alexander’s dissertation:
Glacier hydrology describes water movement around, on, in and under glaciers. Water plays an important role for glacier flow and thus ice transport into the sea and the associated sea level rise. It is important for nutrient transport and release into ecosystems, for hydropower, and for drinking water supply in glaciated regions.
Glacier related flood events are additionally a geohazard risk, emphasizing the importance of accurate knowledge of glacier hydrology to predict such flood events. The knowledge of glacier hydrology, however, is very limited due to general inaccessibility of glacial subsurface flows and thus lack of direct observations and technologies that could provide them.
This doctoral thesis develops novel technologies, allowing to observe and study water flow inside glacial channels in detail. The technics are applied on Svalbard glaciers. For this, sensing drifters are proposed and their statistical repeatability tested. The instruments are then used to study water flow over glacier surfaces. Further, a method to reconstruct flow paths from drifter data is proposed and showcased with the example of a channel within a glacier.
Additional speleological investigations provide permafrost temperatures under Svalbard glaciers and highlight the importance of meteorological glacier surface conditions for temperature and erosion of the glacier bed.
Photo and other information:
Press photo: Andreas Alexander, portrait; 500px. Photo: UiO
Other photo material: Photo with description and credit as specified in the article above, size 1000px.