1. Professor, School of Civil Engineering and Geosciences, Cassie Building, Newcastle Univ., NE1 7RU, U.K. (corresponding author).
2. Hydrologist, Caribbean Institute for Meteorology and Hydrology, Husbands, Barbados.
3. Ph.D. Student, School of Civil Engineering and Geosciences, Cassie Building, Newcastle Univ., NE1 7RU, U.K.
4. Research Fellow, School of Civil Engineering and Geosciences, Cassie Building, Newcastle Univ., NE1 7RU, U.K.
5. Scientific Functionnaire, European Commission Joint Research Centre, Via Fermi, 1, 21020 Ispra (VA), Italy.