Probing Global Photosynthesis for Food Security and Climate Mitigation: The Lens of Solar-Induced Chlorophyll Fluorescence (SIF)

Gross primary productivity (GPP) represents the largest and one of the most dynamic components of the global carbon cycle, yet quantifying its magnitude and future trajectory remains a significant challenge due to the lack of direct measurements at scales beyond the leaf. Over the past 15 years, Solar-Induced chlorophyll Fluorescence (SIF) has emerged as a powerful photosynthetic tracer to bridge this gap, offering a unique opportunity to advance our predictive understanding of carbon-climate feedbacks and food security.

Technological advances have enabled the remote sensing of SIF from satellite platforms with unprecedented precision and resolution. When integrated with terrestrial biosphere models (TBMs), SIF provides a critical constraint for improving the parameterization of global photosynthesis and the coupled dynamics of the carbon and water cycles across both natural and managed ecosystems.

 

In this presentation, I will share our recent findings that empower SIF for multi-scale applications: (1) quantifying global GPP from tower networks to satellite over the globe, (2) enabling scalable crop yield predictions across diverse croppying systems management practices, and (3) partitioning net ecosystem exchange (NEE) and evapotranspiration (ET) across NEON sites spanning a wide range of hydroclimates and plant functional types. Central to these applications is the development of a Mechanistic Light Reaction (MLR) model that establishes a theoretical link between SIF and the actual electron transport rate. We demonstrate that this theory-informed approach significantly improves accuracy, scalability, and interpretability compared to conventional linear scaling and advanced machine learning algorithms, providing a robust framework for reducing uncertainties in ecosystem-scale flux estimates.