1. Civil and Environmental Engineering, Kitami Institute of Technology; Kitami Japan
2. Also at Centre for Water Research, The University of Western Australia; Perth Australia
3. Civil and Environmental Engineering; Tokyo Metropolitan University; Tokyo Japan
4. The Ocean in the Earth System, Max Planck Institute for Meteorology; Hamburg Germany
5. Now at CSIRO, Marine and Atmospheric Research; Perth Australia
6. Coastal, Marine and Disaster Prevention Department, National Institute for Land and Infrastructure Management; Yokosuka Japan