1. a U.K. Centre for Ecology and Hydrology, Wallingford, United Kingdom
2. b National Centre for Earth Observation, Wallingford, United Kingdom
3. c Institute of Atmospheric and Cryospheric Sciences, University of Innsbruck, Innsbruck, Austria
4. d Department of Plateau Atmospheric Physics Research, Northwest, Institute of Eco Environment and Resources, Chinese Academy of Sciences, Beijing, China