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Harvard Forest Symposium Abstract 2014

• Title: Seasonal and diurnal patterns of solar-induced fluorescence as a proxy for canopy photosynthesis
• Primary Author: Xi Yang (Marine Biological Laboratory)
• Additional Authors: John Mustard (Brown University); Jim Tang (Marine Biological Laboratory)
• Abstract:

  Photosynthesis controls the largest flux in the global carbon cycle and is the key to support most of the life on Earth. When plants conduct photosynthesis, fluorescence is always emitted as a by-product. This phenomenon provides a way to estimate photosynthesis using fluorescence. There are few ground-based measurements of solar-induced fluorescence that capture its diurnal and seasonal patterns, especially in forests.
  
  
  
  We developed and installed an automatic system (FluoSpec) in Harvard Forest in 2013. We continuously measured the solar-induced fluorescence (SIF) at 5min interval during the day from June to November. We found that there was a strong control of Photosynthetic active radiation (PAR) on both the diurnal and seasonal cycles of SIF. When comparing with canopy photosynthesis product (GPP) from satellite data, we found a strong linear relationship between SIF and GPP.
  
  
  
  The next step is to compare SIF measurements with eddy covariance measurements at EMS tower. We also plan to incorporate our measurements in a surface energy balance model that explicitly estimate SIF (SCOPE, Van der Tol et al. 2009, Biogeosciences).
  
  

• Research Category: Forest-Atmosphere Exchange