Investigating controls of the variations of solar-induced chlorophyll fluorescence using hyperspectral measurements

Rong Li,  University of Virginia,  rl9pzb@virginia.edu (Presenter)
Koong Yi,  Lawrence Berkeley National Laboratory,  koongyi@lbl.gov
Andrew Jablonski,  University of Virginia,  adj8sh@virginia.edu
Wayne Dawson,  University of Virginia,  wfd2bv@virginia.edu
Jongmin Kim,  University of Virginia,  hvb3hg@virginia.edu
Todd Scanlon,  University of Virginia,  tms2v@virginia.edu
Xi Yang,  University of Virginia,  xiyang@virginia.edu

Solar-induced chlorophyll fluorescence (SIF) has been widely used as a proxy of plant photosynthesis, and its measurements are becoming increasingly available with various spatial and temporal sampling patterns. To fully exploit the available SIF observations from different platforms, it is critical to understand the controls of SIF at different temporal scales. Moreover, it is of particular interest to investigate the response of fluorescence yield, emitted fluorescence per unit radiation absorbed by chlorophyll, to environmental factors due to its link with photosynthetic electron transport.
By combining SIF measurements with hyperspectral visible near-infrared radiation measurements, we decomposed SIF signal into three components representing the variations of illuminations, structure and sun-viewing geometry, and physiology, respectively. We compared how each component affected the diurnal and day-to-day variations of SIF using observations at a flux tower in a temperate mixed forest. While the illumination component explained most of the diurnal variation of SIF, the physiological component explained more day-to-day variation of SIF. Furthermore, we investigated the response of fluorescence yield to environmental factors, including temperature, illumination, and vapor pressure deficit. We found that fluorescence yield was negatively correlated with canopy temperature at the temperate forest site on clear summer days. We also compared the responses of fluorescence yield to the environmental factors with the responses of light use efficiency. This work will facilitate the interpretation of SIF across different temporal scales corresponding to observations from different platforms, improving the use of SIF as a tool for quantifying terrestrial photosynthesis and understanding plant responses to the environment.

Poster Location ID: 2-51

Presentation Type: Poster

Session: Poster Session 2

Session Date: Wed (May 10) 5:15-7:15 PM

CCE Program: TE