ViPS Invited Seminar September 2022

Troy Magney, UC Davis, USA.

Date: 14th September 2022

Time: 13:00

Title: Potential and limitations of remote sensing metrics for tracking ecosystem photosynthesis: Insights from a network of tower spectrometers

Location: Lecture room B5, Forest Sciences Building, Latokartanonkaari 7-9 and remotely via Zoom

Hosts: Maxime Durand & Albert Porcar-Castell

Abstract: It has been a long-standing goal to measure plant physiological function at scales relevant to global biogeochemical cycles, agricultural decision making, and environmental management. Recent advances in remote sensing across the optical domain at a variety of spatial and temporal scales have garnered wide interest from the biogeoscience and earth system science communities to help constrain net fluxes of CO2. While some optical remote sensing approaches (solar-induced fluorescence (SIF) and hyperspectral reflectance) are rapidly growing in popularity, their adoption has introduced a unique set of challenges and uncertainties. This is particularly true when looking at finer spatial (e.g., photosystem, chloroplast, leaf, branch, tree) and temporal (seconds->days) scales. We synthesize findings on the drivers of optical remote sensing (SIF and hyperspectral reflectance) and GPP (or related plant physiological) dynamics from a wide range of spatiotemporal scales, gentotypes and ecosystems (grapevines, almonds, wheat, corn, beans, evergreen forest, boreal forest, tundra, and tropical rainforest). In doing so, we suggest a path forward for end-users of vegetation remote sensing data to 1) constrain greenhouse gas fluxes and 2) inform high-throughput phenotypic of vegetation function based on a more comprehensive understanding of what these signals represent.

Troy Magney is the Principal Investigator of the Plant OPTICS lab at UC Davis. Prior to that he was a NASA Postdoctoral Program Fellow and Research Scientist at the NASA Jet Propulsion Laboratory, in the Carbon Cycle and Ecosystems group. He completed his PhD in Natural Resources at the University of Idaho in 2015. Throughout his career, he has sought to link plant physiological function to proximal remote sensing measurements. The Plant OPTICS lab seeks to better understand plant systems through the lens of remote sensing and environmental data science. The lab is interested in the mechanisms controlling the way photons bounce off or come from plants, and use this to inform our understanding of ecosystem health, productivity, and stress. This work is largely interdisciplinary and combines the fields of plant ecophysiology, biophysics, optics, statistical and computer science. We develop instruments and methods for mapping vegetation structure and function at the leaf, tower, airborne, and satellite scales. This includes optical sensors that measure vegetation reflectance, thermal emission and solar-induced fluorescence (SIF), as well as active sensors (lidar, radar, microwave). 

Read more about Troy's work

Related publications:

Pierrat, Z., Magney, T., Parazoo, N. C., Grossmann, K., Bowling, D. R., Seibt, U., ... & Stutz, J. (2022). Diurnal and seasonal dynamics of solar‐induced chlorophyll fluorescence, vegetation indices, and gross primary productivity in the boreal forest. Journal of Geophysical Research: Biogeosciences, 127(2), e2021JG006588.

Wong, C.Y.S., Bambach, N.E., Alsina, M.M. et al. Detecting short-term stress and recovery events in a vineyard using tower-based remote sensing of photochemical reflectance index (PRI). (2022). Irrigation Science.

Pierrat, Z.,  Nehemy, M. F.,  Roy, A.,  Magney, T.,  Parazoo, N. C.,  Laroque, C., et al. (2021). Tower‐based remote sensing reveals mechanisms behind a two‐phased spring transition in a mixed‐species boreal forest. Journal of Geophysical Research: Biogeosciences,  126, e2020JG006191.

Magney, T. S., Barnes, M. L., & Yang, X. (2020). On the covariation of chlorophyll fluorescence and photosynthesis across scales. Geophysical Research Letters, 47, e2020GL091098. 

Magney, T.S., Bowling, D.R., Logan, B., Grossmann, K., Stutz, J., Blanken, P., Burns, S., Cheng, R., Garcia, M., Kohler, P., Lopez, S., Parazoo, N., Rackza, B., Schimel, D., Frankenberg, C.F. 2019.  Mechanistic evidence for tracking the precise seasonality of photosynthesis with solar-induced fluorescence.  Proceedings of the National Academy of Sciences. 116 (24, 11640-11645.