Implications of Diurnal Changes in Leaf PRI on Remote Measurements of Light Use Efficiency

Matti Mõttus, Juho Aalto, Luiz Aragao, Jaana Bäck, Rocio Hernández-Clemente, Eduardo Eiji Maeda, Vincent Markiet, Caroline J. Nichol, Raimundo Cosme Oliveira, Natalia Restrepo-Coupe, Scott R. Saleska

Forskningsoutput: Kapitel i bok/rapport/konferenshandlingKonferensbidragVetenskapligPeer review


The spectral properties of plant leaves reflect the state of their photosynthetic apparatus and the surrounding environment. A well-known mechanism of photosynthetic downregulation, active on the time scale from minutes to hours, is caused by reversible changes in the xanthophyll cycle pigments. These changes affect leaf spectral absorption and are frequently quantified using the Photochemical Reflectance Index (PRI). This index can thus be used to monitor the photosynthetic status of the vegetation canopy, potentially from a large distance, and allows for a global satellite-based monitoring of photosynthesis. Such Earth observation satellites in near polar orbits usually cover the same geographical location at the same local solar time at regular intervals. To facilitate the interpretation of these instantaneous remote PRI measurements and scale them to longer timescales, we measured the daily course of leaf PRI in two evergreen biomes: European boreal forest and Amazon rainforest. The daily course of PRI was different for the two locations. In Amazon, PRI was driven by incident Photosynthetic Photon Flux Density (PPFD). In the boreal location, PRI and PPFD were decoupled and PRI indicated downregulation only in the afternoon. This downregulation was confirmed with carbon exchange measurements. The study demonstrates the utility of biome-specific daily PRI curves for scaling instantaneous remote measurements to daily values and comparing data acquired at different times of day.
Titel på gästpublikation2018 IEEE International Geoscience & Remote Sensing Symposium : Observing, Understanding And Forecasting The Dynamics Of Our Planet
Antal sidor4
FörlagInstitute of Electrical and Electronics Engineers
Utgivningsdatumnov 2018
ISBN (tryckt)978-1-5386-7151-1
ISBN (elektroniskt)978-1-5386-7150-4 , 978-1-5386-7149-8
StatusPublicerad - nov 2018
MoE-publikationstypA4 Artikel i en konferenspublikation
Evenemang38th IEEE International Geoscience and Remote Sensing Symposium (IGARSS) - Valencia, Spanien
Varaktighet: 22 jul 201827 jul 2018


NamnIEEE International Geoscience and Remote Sensing Symposium proceedings
ISSN (tryckt)2153-6996
ISSN (elektroniskt)2153-7003


  • 1171 Geovetenskaper
  • 1172 Miljövetenskap

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