James F. Spray (a), Paul A. Wilson (a), Steve M. Bohaty (a) & Ian Bailey (b)
(a) Department of Ocean and Earth Sciences, University of Southampton, National Oceanography Center, Southampton SO14 3ZH, UK. E-mail: jfs1g12@soton.ac.uk
(b) Camborne School of Mines, College of Engineering, Mathematics & Physical Sciences, University of Exeter, Cornwall TR10 9FE, UK.