A Polar Approach for Defining a Spatially-Explicit Phenological Year and Quantifying the Degree and Date of Seasonality for Existing Vegetation Across the United States

William W. Hargrove, Danny C. Lee, Steven P. Norman, Forrest Hoffman, and Jitendra Kumar

EFETAC, USDA Forest Service, EFETAC, USDA Forest Service, EFETAC, USDA Forest Service, Oak Ridge National Laboratory, and Oak Ridge National Laboratory