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Title: Arctic fjords : simplified modelling and the role of freshwater
Author: Drysdale, Lewis A.
ISNI:       0000 0004 7425 7730
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2017
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Defining the role of freshwater in a fjord is important to further the understanding of seasonal physical variability in fjordic systems because the variability of freshwater flux is a key control on fjord oceanography, yet information on freshwater inputs to Svalbard fjords is currently lacking. In this study, two methods of studying fjords are utilised. Firstly, seawater samples and oceanographic profiles were collected from four fjords and shelves around the high-Arctic Svalbard archipelago between September 2013 and April 2015. Analysis of the seawater samples showed that surface meteoric water in a glaciated west-Svalbard fjord was present in quantities up to four times as much (∼18%) assea-ice melt (∼5%). In comparison, a north-Svalbard fjord had more than twice as much sea-ice melt (∼5%) as meteoric water (∼2%). Four contrasting regions of freshwater infuence around the Svalbard archipelago were established, defined by their freshwater processes. Further analysis of data suggest that coastal currents act as an upstream freshwater source, and are also enhanced by freshwater along their path. Upper layer circulation, meanwhile, was seen to be an important mode of dispersal of freshwater inputs from smaller inlets. Secondly, a box model was modified by the inclusion of a sea ice model and was run to understand the leading-order processes and mechanisms observed in Arctic fjords. Model results were successfully validated against four years of oceanographic data from a mooring deployed between 2008–2013 in a restricted exchange fjord on Svalbard and represented the seasonal cycle of a high-Arctic fjord including sea-ice growth and convection. The model showed that varying the sill geometry of a high-Arctic fjord impacts the formation of sea-ice and the dominant modes of exchange. The model also showed that warming of the sub-surface temperature causes excess heat inside fjords, which impacts on sea-ice production and (although not shown) is highly likely to cause accelerated melting of tidewater glaciers.
Supervisor: Not available Sponsor: Natural Environment Research Council ; Scottish Association for Marine Science
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Fjords ; Fresh water