The ocean current system off Southern Greenland is a key component of the Earth’s climate system due to its role in the regulation of the global thermohaline circulation. A combination of historic and new observational data, supported by modelling simulations, has revealed great complexity in both the surface and deep currents of the area. A comprehensive review of the available hydrographic data for the South-East Greenland shelf has shown that the observed spatial variability in the transport of the on-shelf East Greenland Coastal Current is inconsistent with the theory that it is primarily driven by local fjord runoff. A high resolution regional modelling study supports these observations and suggests that the East Greenland Coastal Current is primarily the result of a bifurcation of the East Greenland Current in the vicinity of Denmark Strait. Model simulations also suggest that the pathways followed by the low salinity output of the region’s fjord complexes are influenced by the strength and position of the main East Greenland Current. New data collected in the vicinity of Cape Farewell, on the southern tip of Greenland, has also revealed more complex behaviour in the Deep Western Boundary Current. The significant spatial variability in Deep Western Boundary Current transport observed in the region of Cape Farewell suggests that the confluence of Denmark Strait Overflow Water and Iceland Scotland Overflow Water occurs over a wider geographic area than is commonly suggested. A review of historic data indicates that these spatial patterns vary over timescales of months and upwards. It is hypothesised that strands of overflow water follow different depth controlled pathways dependent on their relative water density in comparison with the surrounding water masses. This has significance for the way deep current strength proxies in the region are interpreted in relation to climatic variations. Time series data for a single location may well overestimate the variability in the Deep Western Boundary Current further south due to path switching of the flow. In the future more complete observational datasets combined with more advanced oceanographic and coupled climate models will provide a better understanding of the interaction between the regional current system, the global current system and the climate system. This will enable more reliable prediction of the impact of global warming and, in particular, the potential influence of accelerated Greenland ice cap melting on the global ocean circulation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:515879 |
| Date | January 2008 |
| Creators | Wilkinson, David |
| Publisher | University of Southampton |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://eprints.soton.ac.uk/145833/ |
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