1. Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA.
2. Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
3. Land Surface Hydrology Research Group, Civil and Environmental Engineering, University of Washington, Seattle, WA 98195, USA.
4. National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
5. U.S. Geological Survey, La Jolla, CA 92093, USA.