1. School of Earth and Environmental Sciences, University of St Andrews, St Andrews KY16 9TS, United Kingdom
2. School of Geography, Development and Environment and Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721
3. Division of Hydrologic Sciences, Desert Research Institute, Reno, NV 89512
4. Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523
5. Climate and Environmental Physics & Oeschger Centre for Climate Change Research, Universtity of Bern, Bern 3012, Switzerland