Projection of North Atlantic thermal anomalies onto the European Shelf Seas

MASTS/E3 PhD Studentship
Project Description: Warming of the global ocean over the past few decades has been particularly pronounced over the North Atlantic. However, in the N Atlantic variations about this trend are large, and often of opposing sign between sub-polar and sub-tropical gyres1. The western European shelf seas are heavily influenced by the adjacent eastern north Atlantic2, which in turn draws source waters from both the sub-tropical and sub-polar gyres to a varying degree3. Basin-scale indices are often used as simple indicators of an ocean’s “state”, particularly when large scale oscillations between two such “states” seem to describe a major mode of variability (the Southern Oscillation Index, or SOI, is the best-known example). Two indices are often used to describe the large scale state of the Atlantic ocean, the North Atlantic Oscillation index (NAO) and the Atlantic Multi-decadal Oscillation (AMO). Shelf water physical and biochemical characteristics correlate with the former index2,4, and ecosystem changes in coastal areas show correlation with the latter index5, though in neither case is causality well described. Shelf and coastal seas are bounded by the ocean, land and atmosphere; ocean/shelf exchange is physically complex6, terrestrial influences are regionally variable, and atmospheric coupling is strong. At present, the only shelf index which is well described maps the competition between tidal mixing and solar heating7. From this view point there is view growing in acceptance that a global warming trend will lead to more highly stratified shelf seas, and reduced productivity; however this view is local, and neglects oceanic influence of the contrasting nutrient loading of the two N Atlantic gyres.

This project will seek to answer the questions: 1) Can well-described indices be developed for shelf seas which account for inter-annual to inter-decadal modes of variability? 2) Are there physical explanations that account for these implied links?

The rationale behind this project is to better understand the mechanistic links between ocean modes and properties of shelf and coastal seas; whether they be predominantly oceanic or if atmospheric changes, in addition, have a significant role. The testable hypotheses are:
• T/S water mass relationships associated with adjacent ocean modes are imprinted on shelf seas.
• Variations in stratification (strength and/or seasonal duration) in shelf seas respond to adjacent ocean modal indices.
• Indices can be derived to describe major multi-annual modes of variation in shelf seas

Year 1: Literature review of previous work, focussing on in decadal trends in oceanic and atmospheric data sets indices. Training in statistical time series analysis methods (e.g. PCA, EOF and variants). Familiarisation with geochemical proxy methodologies. Training in handling large data sets (numerical model output). Refinement of research questions and hypotheses.

Year 2: Collection of archive water property, geochemical and modelled data. Derivation of exiting index metrics. Investigation of major decadal modes of variation in shelf sea records (instrumental, proxy and modelled). Derivation of appropriate indices for shelf response. Attendance at relevant discipline-based summer training school.

Year 3: Statistical and causal (mechanistic) investigation of existing and newly derived indices. Presentation of results at national or international meeting. Writing and submission of thesis.

Applicants should apply by submitting an application form, CV and referees comments to Fiona Wallace, Academic Registry Officer Postgraduate, The Scottish Association for Marine Science, Oban, Argyll, PA37 1QA or by email to [Email Address Removed]. Please visit SAMS website for application procedure http://www.sams.ac.uk/education/postgraduate

Students will be registered with the University of Edinburgh and based at SAMS.

Closing date for applications is 14th July 2014.
Interviews are expected to take place week beginning 21st July 2014.