Basal glacial melting and its contribution to bottom water formation and ocean circulation in the Antarctic continental margins under changing environmental conditions.



Dr. Oliver Huhn
Universität Bremen
Institut für Umweltphysik
Abteilung Ozeanographie


Project Description

In the Weddell Sea, the actual state of basal ice shelf melting, its variability and possible future trends due to changing climate conditions are not yet fully understood. To study and to understand its impact on the Antarctic Bottom Water composition and formation rate and related variability as well as the impact on the global ocean circulation more tracer observations are urgently needed. The aims of the proposed project are: A) To produce an improved actual estimate of basal glacial melt water inventories and basal melting rates for the ice shelves in the western (Larsen Ice Shelf) and southern Weddell Sea (Filchner Ice Shelf) to be able to address temporal trends in the future B) To trace the pathways of the basal melt water, how it contributes to local Antarctic Bottom Water formation, and to quantify the related actual Antarctic Bottom Water formation rates. C) To investigate, if there is evidence for local shifts or temporal trends in glacial melting processes and related Antarctic Bottom Water formation. Possible changes could be related to changes in the ice shelves, as Larsen A, B are now ice free, in contrast to Larsen C and Filchner, which both are still ice covered, or to changing properties or circulation of ambient water masses. D) To assess, how local processes and their variability are related to basin wide or global scales (e.g. observed basin wide Antarctic Bottom Water property changes, warming, freshening, age increase and declining ventilation, slow down anthropogenic carbon uptake, declining volumes, trends). Tracer observations will help substantially to investigate and quantify basal glacial melting (stable noble gas isotopes [3He, 4He, Ne] to quantify basal glacial melt water inventories), basal melt rates and Antarctic Bottom Water formation (transient trace gases [CFCs] to determine transit time scales [TTDs], formation rates, and the related anthropogenic carbon uptake) and their variability. These objectives contribute to three major goals of the SPP 1158: * Dynamics of the Climate System Components * Response to Environmental Change * (The Weddell Sea as a) Gateway to Lower Latitudes


DFG Programme: Infrastructure Priority Programmes

Term from 2014 to 2018