1. International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama 36849 USA
2. Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA
3. Department of Biological Sciences, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79902 USA
4. Department of Civil and Environmental Engineering, Washington State University, Pullman, Washington 99164 USA
5. Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 China
6. NOAA Earth System Research Laboratory, 325 Broadway, Boulder, Colorado 80305-3337 USA
7. Department of Earth and Planetary Science, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138 USA