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Applications of 3-dimensional electromagnetic induction by sources in the ocean

Objective



This proposal is for an integrated development programme aimed at improving the environmental and scientific exploitation of measurements of electromagnetic fields induced in the oceans, and so of providing direct benefits to the environmental and scientific objectives of the MAST III programme. Electric and magnetic fields are induced in the oceans by both natural and artificial sources. Measurements of these induced fields have a wide range of applications in both physical oceanography and geophysics. All applications are linked by identical physics and by the interaction, over a wide range of frequencies, between induced fields in the water column and the underlying earth. Fields induced naturally can result from sources in the ocean itself, or from external sources (such as ionospheric disturbances). Those with the greatest potential applications for oceanographic purposes are from internal sources within the oceans, and relate to the movement of water masses through the earth's magnetic field. Similarly, artificial sources within the ocean, close to the sea floor, can be used in controlled source electromagnetic (CSEM) sounding for geophysical applications. Two rapidly developing areas of technology seek specifically to exploit internal induction in the oceans for scientific and environmental purposes. The first is the use of submarine cables or ocean bottom EM instruments to monitor water mass movements at tidal or longer periods. The second is the CSEM technique, which - while still in an early developmental stage - is already contributing to important advances in marine geoscience. However the continuing development of both of these applications suffers at present from the absence of a computer modelling code, capable of predicting the electric and magnetic fields induced by an arbitrary, 3-Dimensional source in a 3-Dimensionallyvarying electrical resistivity structure.

We propose an integrated, phased and multi-disciplinary programme of research to: i) generate and test a suitable numerical modelling code; (ii) use the code to carry out a series of modelling studies relating to both oceanographic and geophysical uses of natural and artificial sources; and (iii) carry out a demonstration 3-D CSEM experiment on a hydrothermally active site on the ocean floor in European waters, and interpret the results using the newly developed code.

Objective (i) will provide an absolutely essential tool for future exploitation of EM fields in the oceans. Objective (ii) will provide many important new insights into the nature of induction and its applications, and will lead to improved utilisation of existing and future EM measurements for determining and monitoring ocean circulation. Objective (iii) will provide European marine science with a unique instrumental and interpretational capability, unavailable anywhere outside Europe, that has a wide range of scientific, environmental and industrial applications across several sectors. This proposal brings together a new consortium of four European partners with individual expertise in different areas of marine science, in order to promote rapid progress in this important area of technological development and across all of its applications.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSITY OF SOUTHAMPTON
Address
Southampton Ocenagraphic Centre, European Way
SO14 3ZH Southampton
United Kingdom

Participants (4)

HALO LIMITED
Iceland
Address
16,Sidumuli 31
128 Reykjavik
INSTITUTO DE CIENCIAS DA TERRA E DO ESPACO
Portugal
Address
58,Rua Da Escola Politecnica 58
1269-102 Lisboa
JOHANN WOLFGANG GOETHE UNIVERSITAET FRANKFURT
Germany
Address
Georg-voigt-strasse 14
60325 Frankfurt Am-main
NATURAL ENVIRONMENT RESEARCH COUNCIL
United Kingdom
Address
North Star Avenue, Polaris House
SN2 1EU Swindon