Biogeosciences, 17, 405–422, 2020 https://doi.org/10.5194/bg-17-405-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. A double peak in the seasonality of California’s photosynthesis as observed from space Alexander J. Turner1,2,3, Philipp Köhler4, Troy S. Magney3,4,5, Christian Frankenberg3,4, Inez Fung1, and Ronald C. Cohen1,2 1Department of Earth and Planetary Sciences, University of California, Berkeley, CA 94720, USA 2College of Chemistry, University of California, Berkeley, CA 94720, USA 3Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA 4Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91226, USA 5Department of Plant Sciences, University of California, Davis, CA 95616, USA Correspondence: Alexander J. Turner (
[email protected]) Received: 24 September 2019 – Discussion started: 26 September 2019 Revised: 16 December 2019 – Accepted: 6 January 2020 – Published: 29 January 2020 Abstract. Solar-induced chlorophyll fluorescence (SIF) has nia’s photosynthesis is due to two processes that are out of been shown to be a powerful proxy for photosynthesis and phase: grasses, chaparral, and oak savanna ecosystems show gross primary productivity (GPP). The recently launched an April maximum, while evergreen forests peak in June. TROPOspheric Monitoring Instrument (TROPOMI) features An empirical orthogonal function (EOF) analysis corrobo- the required spectral resolution and signal-to-noise ratio to rates the phase offset and spatial patterns driving the double retrieve SIF from space. Here, we present a downscaling peak. The EOF analysis further indicates that two spatiotem- method to obtain 500 m spatial resolution SIF over Cal- poral patterns explain 84 % of the variability in the SIF data.