Seasonal Cycle of Solar Fraunhofer Line Filling in the Near-IR and its Relationship to Vegetation Phenology and Global Primary Productivity (GPP).

摘要

Global mapping of terrestrial vegetation fluorescence from space has recently been accomplished. These data can potentially provide global information related to gross primary productivity (GPP), particularly the length of the growing season, that may be of use for global carbon cycle modeling. Here, we compare a satellite-derived additive signal at 866 nm from the SCIAMACHY satellite instrument directly with a diverse set of North American tower-based GPP estimates. The satellite signal is presumably due primarily to fluorescence from chlorophyll and/or other compounds in vegetation. For some vegetation types, the SCIAMACHY signal captures the spring onset and autumn shutoff of photosynthesis. In contrast, GPP from models that rely on satellite reflectance-based vegetation parameters over-estimates the length of the growing season for some biomes. Satellite fluorescence measurements therefore show potential for improving model GPP estimates.