1. College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China
2. Department of Atmospheric and Oceanic Sciences & Institute of Atmospheric Sciences, Fudan University, Shanghai 200438, P. R. China
3. Meteorological Observation Centre of China Meteorological Administration (MOC/CMA), Beijing 100081, P. R. China
4. Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
5. College of Environmental Sciences and Engineering, Peking University, Beijing 100871, P. R. China