1. Research Hydrologist, Lincoln Environmental Research, Hamilton, New Zealand; formerly, Institute of Hydrology and Meteorology, Dresden Univ. of Technology, Würzburger Str. 46, 01187 Dresden, Germany (corresponding author).
2. Professor, Institute of Hydrology and Meteorology, Dresden Univ. of Technology, Würzburger Str. 46, 01187 Dresden, Germany.