| Summary: | Land surface phenology (LSP) and ground phenology (GP) are both important sources of information for monitoring terrestrial ecosystem responses to climate changes. Each measures different vegetation phenological stages and has different sources of uncertainties, which make comparison in absolute terms challenging, and therefore, there has been limited attempts to evaluate the complementary nature of both measures. However, both LSP and GP are climate-driven and, therefore, should exhibit similar inter-annual variation. LSP obtained from the whole time-series of MERIS data were compared to thousands of deciduous tree ground phenology records of the Pan European Phenology network (PEP725). Correlations observed between the inter-annual time-series of the satellite sensor estimates of phenology and PEP725 records revealed a close agreement (especially for Betula Pendula and Fagus Sylvatica species). In particular, 90% of the statistically significant correlations between LSP and GP were positive (mean R2?=?0.77). A large spatio-temporal correlation was observed between the dates of the start of season (end of season) from space and leaf unfolding (autumn coloring) at the ground (pseudo R2 of 0.70 (0.71)) through the application of non-linear multivariate models, providing, for the first time, the ability to predict accurately the date of leaf unfolding (autumn coloring) across Europe (RMSE of 5.97?days (6.75?days) over 365?days)
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