Tracking vegetation phenology across diverse North American biomes using PhenoCam imagery

Author(s): Richardson, AD; Hufkens, K; Milliman, T; Aubrecht, DM; Chen, M; Gray, JM; Johnston, MR; Keenan, TF; Klosterman, ST; Kosmala, M; Melaas, EK; Friedl, MA; Frolking, S | Abstract: © The Author(s) 2018. Vegetation phenologycontrols the seasonality of many ecosystem processes, as well as numerous biosphere-atmosphere feedbacks. Phenologyis also highly sensitive to climate changeand variability. Here we present a series of datasets, together consisting of almost 750 years of observations, characterizing vegetation phenologyin diverse ecosystems across North America. Our data are derived from conventional, visible-wavelength, automated digital camera imagery collected through the PhenoCam network. For each archived image, we extracted RGB (red, green, blue) colour channel information, with means and other statistics calculated across a region-of-interest (ROI) delineating a specific vegetation type. From the high-frequency (typically, 30 min) imagery, we derived time series characterizing vegetation colour, including "canopy greenness", processed to 1- and 3-day intervals. For ecosystems with one or more annual cyclesof vegetation activity, we provide estimates, with uncertainties, for the start of the "greenness rising" and end of the "greenness falling" stages. The database can be used for phenologicalmodel validation and development, evaluation of satellite remote sensing data products, benchmarking earth systemmodels, and studies of climate change impacts on terrestrial ecosystems.