Prostar

Prostar estimates terrestrial gross primary productivity (GPP) using chlorophyll fluorescence (ChlF) measurements across leaf, canopy, and ecosystem scales.

Key Features:

• Cross-scale ChlF integration: Captures seasonal variations in photosynthesis with reported linear relationships between ChlF and photosynthesis of R² = 0.73 (leaf), R² = 0.77 (canopy), and R² = 0.86 (satellite).
• GPP modeling from SIF and leaf ChlF: Estimates GPP using solar-induced chlorophyll fluorescence (SIF) from tower measurements combined with leaf-level ChlF parameters, with model agreement to flux tower observations reported as R² = 0.68.
• Leaf fluorescence parameter identification: Identifies the fraction of absorbed photons used for photochemistry (leaf Fq'/Fm') as the strongest leaf-level correlate of canopy SIF yield (R² = 0.79).
• Correlations with canopy structure and biochemistry: Relates canopy SIF and SIF-derived GPP (GPP_SIF) to chlorophyll content (R² = 0.65), leaf area index (LAI) (R² = 0.35), and normalized difference vegetation index (NDVI) (R² = 0.36).

Scientific Applications:

• Photosynthesis research: Supports analysis of photosynthetic processes and their seasonal dynamics across leaf, canopy, and ecosystem scales using ChlF measurements.
• Carbon cycle and climate studies: Provides GPP estimates for studies of carbon cycling and climate-related ecosystem responses.
• Remote sensing validation: Enables linking of leaf-level ChlF and canopy SIF with satellite-scale observations and validation against flux tower data.
• Ecological monitoring: Facilitates monitoring of ecosystem biophysical and biochemical status via relationships among SIF, GPP_SIF, chlorophyll content, LAI, and NDVI.

Methodology:

Examines seasonal relationships between ChlF and photosynthesis at leaf, canopy, and satellite scales within a temperate deciduous forest and develops models linking leaf-level fluorescence parameters (including Fq'/Fm') with canopy-scale SIF and flux tower GPP observations.