New Methods to Measure Photosynthesis from Space

August 26-31, 2012
California Institute of Technology - Pasadena, CA 91125

Final Report

Workshop Overview:

Our ability to close the Earth's carbon budget and predict feedbacks in a warming climate depends critically on knowing where, when and how carbon dioxide (CO2) is exchanged between the land and atmosphere. A new generation of satellite missions such as GOSAT and OCO-2 aim at retrieving column-averaged mixing ratios of atmospheric CO2 with sufficiently high accuracy and precision to enable inversions of land-atmosphere CO2 fluxes (so called top-down approach), greatly reducing uncertainties in biospheric net fluxes. However, a complementary bottom-up approach is needed to understand how biological processes control this net flux. For example, both the magnitude and its seasonality of photosynthesis (commonly referred to as GPP) are uncertain, and we currently have no direct means of assessing this flux.

The focus of this workshop is on a newly developed capacity to monitor chlorophyll fluorescence from terrestrial vegetation by satellite. This new retrieval promises to provide direct and spatially resolved information on GPP, an ideal bottom-up complement to the atmospheric net CO2 exchange inversions. Sunlight absorbed by chlorophyll in photosynthetic organisms is mostly used to drive photosynthesis, but some can also be dissipated as heat or re-radiated at longer wavelengths (660-800 nm). This re-emitted light is termed solar-induced chlorophyll fluorescence (Fs) and has been found to strongly correlate with GPP.

We will leverage our efforts on previous studies and workshops related to the ESA Earth Explorer FLEX mission concept. These studies, mostly focused on canopy and leaf-level interpretation, will provide the ground-work for our workshop, which will be focused on the global carbon cycle and synergies with atmospheric net flux inversions. Our primary goal is thus to advance our understanding of Fs and its relation to GPP and environmental stress at the planetary scale.

Workshop Participants:

  • Ian Baker - Colorado State University
  • Joseph Berry - Carnegie Institution for Science
  • Kevin Bowman - JPL
  • Saulo Castro-Contreras - University of Alberta
  • Maria Pilar Cendrero-Mateo - University of Arizona
  • Alexander Damm - University of Zurich
  • Darren Drewry - JPL
  • Bethany Ehlmann - Caltech
  • Joshua Fisher - JPL
  • Jaume Flexas - Universitat de les Illes Balears
  • Christian Frankenberg - JPL
  • John Gamon - University of Alberta
  • Bernard Genty - CNRS CEA Cadarache
  • Luis Guanter - University of Oxford
  • Thomas Hilker - Oregon State University
  • Le (Elva) Kuai - JPL
  • Joanna Joiner - NASA Goddard Space Flight Center
  • Martin Jung - Max Planck Institute for Biogeochemistry
  • Jung-Eun Lee - JPL
  • Junjie Liu - JPL
  • Anna Michalak - Carnegie/Stanford
  • Charles Miller - JPL
  • Christopher O'Dell - Colorado State University
  • Nicholas Parazoo - JPL
  • Albert Porcar-Castell - University of Helsinki
  • Christopher Schwalm - Northern Arizona University
  • Christian Van der Tol - ITC-University of Twente
  • Paul Wennberg - Caltech
  • Debra Wunch - Caltech

Short Course Presentations

Ian Baker
Colorado State University

The Global Carbon Cycle
(38 MB .pdf)

Joe Berry
Carnegie Institution for Sciences, Stanford

A Primer into Photosynthesis and Chlorophyll Fluorescence
(16.8 MB .pdf)

Christian Frankenberg

Retrieval of Chlorophyll Fluorescence from Space
(50.4 MB .pdf)

Workshop Presentations

Team Leads

Workshop Goals and Objectives
(84 KB .jpg)

Bernard Genty
CNRS CEA Cadarache

The Basic Relationships Between Chlorophyll Fluorescence and Photosynthesis in Plants
(6.55 MB .pdf)

Joanna Joiner

Challenges in Retrieving and Using Space-Based Fluorescence
(900 KB .pdf)

Luis Guanter
Free University Berlin

USARecap of Fluorescence Retrieval Techniques from Ground and Space (I/II)
(1.3 MB .pdf)

Alexander Damm
University of Zurich

Fluorescence: Lessons Learned from Ground-Based and Airborne Studies
(7 MB .pdf)

Jaume Flexas
University of Zurich

Stress Responses of Terrestrial Vegetation and Their Manifestation in Fluorescence and GPP
(1.6 MB .pdf)

Martin Jung
Max Planck Institute for Biogeochemistry

Statistical Modelling (Upscaling) of Gross Primary Production (GPP)
(6 MB .pdf)

Christiaan van der Tol
ITC-University of Twente

Scaling Flourescence from Leaf to CanopyScaling Flourescence from Leaf to Canopy
(996 KB .pdf)

J. Albert Porcar-Castell
Univeristy of Helsinki

From Leaf-Level Flourescence to Regional GPP: Open Questions and Challenges
(856 KB .pdf)

Ian Baker
Colorado State University

How Can We Exploit Fluorescence Simulations and Retrievals?
(2.4 MB .pdf)

Paul Wennberg

Determining Fluxes of CO2 using Mass Constraints
(3.5 MB .pdf)

Thomas Hilker
Oregon State University

Improved Estimates of Vegetation Carbon Cycle Components
(4.9 MB .pdf)

Anna Michalak
Carnegie Institution for Sciences, Stanford

A Bird's Eye View of the Carbon Cycle
(9 MB .pdf)

Luis Guanter
Free University Berlin

What others observations are needed in addition to Fs for a Fobust GPP estimate?
(1.3 MB .pdf)

Nick Parazoo

Complementary Estimates of Carbon Pools from Fs and CO2
(11.5 MB .pdf)