1. School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, U.K.
2. Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ, U.K.
3. Grantham Institute - Climate Change and the Environment, Imperial College London, London SW7 2AZ, U.K.
4. Regional Initiative for Hydrological Monitoring of Andean Ecosystems, Lima, Peru