1. National Oceanic and Atmospheric Administration (NOAA)/National Climatic Data Center, 151 Patton Avenue, Asheville, NC 28801, USA.
2. National Center for Atmospheric Research, Boulder, CO 80303, USA.
3. Integrative Biology, University of Texas, Austin, TX 78712, USA.
4. Illinois State Water Survey, Champaign, IL 61820, USA.