Global Retrievals of Solar-Induced Chlorophyll Fluorescence With TROPOMI

The TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor satellite was launched in October 2017 and collected more than 2.5 billion single measurements since then. Thanks to TROPOMI's spectral coverage, resolution, and radiometric accuracy, we are able to retrieve solar-induced chlorophyll fluorescence (SIF) in a way which exceeds previous and existing capabilities for a spatial continuous monitoring of SIF from space. In this contribution, we will provide a brief overview of the approach(es) to retrieve SIF in both red and far-red wavelengths, demonstrate the potentials and pitfalls based on selected case studies, and present comparisons with independent data sets to underscore the high quality of TROPOMI's SIF retrievals. In particular, we compare the far-red SIF retrievals to those from OCO-2 (Orbiting Carbon Observatory-2) over terrestrial surfaces as well as the red SIF retrievals to the fluorescence line height measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) over ocean.