Synthetic ARC retrieval → local weather → radiation partitioning → proxy SIF model → parameter optimisation. All plots visible — scroll to follow the causal chain.
LAI drives canopy absorption, Rin drives illumination, and their product (scaled by fqe) controls the proxy SIF signal. The three curves share the same time axis so the seasonal coupling is immediately visible.
Total shortwave (Rin) is split into direct beam and diffuse sky components using the Erbs (1982) clearness-index model. The diffuse fraction controls how much light penetrates deep into the canopy.
The proxy model generates a SIF-like signal from the canopy and radiation
inputs. The optimiser adjusts fqe (fluorescence quantum efficiency) from
0.0080 to 0.0179 to match the noisy synthetic observations,
reducing RMSE from 0.0822 to 0.00253.