The Solar-Induced Chlorophyll Fluorescence Spectral Imager: Design and Data Quality

Solar-induced chlorophyll fluorescence (SIF) remote sensing technology is a frontier in the fields of Ecological Environment, Carbon Cycle, and Quantitative Remote Sensing. The newly launched Terrestrial Ecosystem Carbon Inventory Satellite (TECIS) is equipped with the first in-orbit payload, Fluorescence Spectral Imager (FSI), which is dedicated to high spatial resolution imaging of SIF. FSI has improved its spatial resolution to 350 m × 800 m, with a spectral resolution of 0.24 nm. FSI adopts a dual diffuse reflection system to obtain solar radiation and Fraunhofer lines for wavelength and radiation calibration. The residual error after wavelength correction is less than 0.002nm, and no wavelength drift has been identified in 10 months of continuous operation. The SIF products of FSI data processing can effectively reflect the state of surface vegetation. FSI operates stably in orbit, obtaining high-precision calibration and observation data that can support forest ecological monitoring, vegetation photosynthesis, and stress effects research, as well as GPP inversion.