Temperature Sensitivity of Canopy Photosynthesis Phenology in Northern Ecosystems.

摘要

Northern Hemisphere terrestrial ecosystems have been recognized as areas with large carbon uptake capacity and sinks and are sensitive to temperature change. However, the temperature sensitivity of ecosystem carbon uptake phenology in different biomes of northern ecosystems has not been well explored. In this study, based on our previous effort in characterizing canopy photosynthesis phenology indices, we analyzed how these phenology indices responded to temperature changes by using spatial temperature variability in the temperate and boreal ecosystems in the north hemisphere. Eddy covariance flux measurements of canopy photosynthesis were used to examine the temperature sensitivity of canopy photosynthesis phenology in different biomes and seasons (spring and autumn). Over all the 68 sites, the upturning day, peak recovery day, peak recession day, and senescence day of canopy photosynthesis were all sensitive to mean annual air temperature.