Abstract:

Phenology focuses on the timing of biological events in organisms as influenced by both abiotic and biotic factors. In contrast, land surface phenology (LSP) focuses on the temporal development of the vegetated land surface as influenced primarily by abiotic factors. This shift in focus affects how we observe, describe, characterize, and model land surface phenologies. The most studied phenological transition (or phenophase) is vernal green-up in temperate and boreal climates, when vegetation recommences growth and development following winter dormancy. The timing of interest as it signals widespread changes in the surface radiation and energy budgets and exchanges of water, carbon, and trace gases between the land and the atmospheric boundary layer. The typical modality for LSP observations are spaceborne spectrometers tracking the differential reflectance in red and near infrared wavelengths, but it is also possible to use other forms of electromagnetic radiation to sense and measure phenophases and associated abiotic seasonalities. This talk will review some history of land surface phenology, describe current practices, challenges, and fallacies, and look to the prospects for improving characterizations of LSPs in a changing world.