http://hdl.handle.net/1807/103407

Leng, Jiye (2020) Downscaling the Maximum Carboxylation Rate (Vcmax) Derived from Satellite Sun-induced Chlorophyll Fluorescence Data Using High-resolution Remote Sensing Products, Tspace - Theses, http://hdl.handle.net/1807/103407

The maximum carboxylation rate (Vcmax) influences the magnitude of gross primary productivity (GPP). Currently, reliable global Vcmax products derived from satellite sun-induced chlorophyll fluorescence (SIF) data are at coarse resolutions, which cannot meet the demand of global ecological research. In this thesis, the Vcmax25 (Vcmax normalized to 25°C) dataset derived from satellite SIF at a coarse resolution (0.1°, ~11 km) is downscaled to a higher resolution (1 km) through a downscaling scheme using photochemical reflectance index (PRI) and spatial scaling algorithms based on leaf chlorophyll content (LCC) and normalized difference vegetation index (NDVI). The Boreal Ecosystem Productivity Simulator (BEPS) is used to evaluate the downscaled Vcmax25 using tower flux data. The results show that the LCC-downscaled Vcmax25 data appreciatively improve GPP simulations at the tower sites, indicating LCC as a feasible way for downscaling the Vcmax25 dataset. GPP estimations at the 0.1° resolution decrease by 2-7% after Vcmax25 downscaling.

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