1. Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, and Joint Center for Global Change Studies (JCGCS) Tsinghua University Beijing China
2. Now at Cooperative Programs for the Advancement of Earth System Science University Corporation for Atmospheric Research Boulder CO USA
3. Now at NOAA/Geophysical Fluid Dynamics Laboratory Princeton NJ USA
4. School of Marine and Atmospheric Sciences Stony Brook University Stony Brook NY USA