PhD defence by Antje Fitzner – Københavns Universitet

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PhD defence by Antje Fitzner

Modeling the tidewater glacier Kangiata Nunaata Sermia and the freshwater flux into Godthåbsfjorden


Abstract - English (in danish below)
The Greenland ice sheet loses mass due to changing surface mass balance, direct melting on the surface, ice flow through the numerous outlet glaciers, and basal melt. This Ph.D. thesis focuses on the outlet glaciers terminating in Godthåbsfjord near Nuuk in West Greenland, with Kangiata Nunaata Sermia (KNS) being the main contributing glacier. The mass loss of this glacier forms a small contribution to the total mass loss of the Greenland ice sheet, but it will have a large impact on the local ecosystem when there is a large freshwater flux into the fjord. Here, two independent methods are used to estimate the total mass loss by KNS and its neighboring outlets, namely the ice sheet model PISM applied to KNS and stable oxygen isotope measurements in the fjord. Both studies show that KNS is currently losing mass. Prognostic studies show that KNS will likely continue to lose mass.

Abstract - dansk
Den grønlandske indlandsis oplever et massetab på grund af ændringer i overfladens massebalance, direkte afsmeltning af overfladen, isflydning fra talrige gletsjere og smeltning ved bunden. Denne Ph.D. afhandling fokuserer på de udløbsgletsjere, der flyder ud i Godthåbsfjorden ved Nuuk i Vestgrønland, hvor Kangiata Nunaata Sermia (KNS) er den primære  udløbsgletsjer. Massetabet fra denne gletsjer udgør en lille del af det samlede massetab fra Grønlands indlandsis, men det kan have stor indflydelse på det lokale økosystem, når store mængder ferskvand tilføres fjorden. I denne Ph.D. afhandling anvendes to uafhængige metoder til at estimere det samlede massetab fra KNS og dens nabogletsjere: en isflydemodel (PISM) af KNS og målinger af stabile ilt-isotoper i fjorden. Begge undersøgelser viser, at KNS øjeblikket mister masse. Prognostiske undersøgelser viser, at sandsynligvis vil KNS fortsætte med at miste masse.

Supervisor
Dorthe Dahl-Jensen, Centre for Ice and Climate

Assessment committee
Christine Hvidberg, Centre for Ice and Climate
Jason Box, GEUS
Richard Hindmarch

If interested please contact Antje Fitzner for a copy of the thesis.