Gross photosynthetic CO2 uptake is the single largest component of the global carbon cycle and a crucial variable for monitoring and understanding global biogeochemical cycles and fundamental ecosystem services. Nowadays routine measurements of the net biosphere-atmosphere CO2 exchange are conducted at the ecosystem scale in a large variety of ecosystem types across the globe. Gross photosynthetic and ecosystem respiratory fluxes are then typically inferred from the net CO2 exchange and used for benchmarking of terrestrial biosphere models or as backbones for upscaling exercises. Uncertainty in the responses of photosynthesis and respiration to the climate and environmental conditions is a major source of uncertainty in predictions of ecosystem-atmosphere feedbacks under climate change. On the other hand transpiration estimates both at ecosystem to global scales are highly uncertain with estimates ranging from 20 to 90 % of total evapotranspiration. The most important bottleneck to narrow down the uncertainty in transpiration estimates is the fact that direct measurements of transpiration are uncertain and techniques like eddy covariance measure only the total evapotranspiration.
During the last decade, technological developments in field spectroscopy, near surface remote sensing, isotope flux measurements and quantum cascade lasers have enabled alternative approaches for constraining ecosystem-scale photosynthesis, respiration and transpiration. On the other hand a variety of approaches have been developed to directly assess the gross fluxes of CO2 and transpiration by using both process based and empirical models, and machine learning techniques.
In this session we aim at reviewing recent progress made with novel approaches of constraining ecosystem gross photosynthesis, respiration and transpiration and at discussing their weaknesses and future steps required to reduce the uncertainty of present-day estimates. To this end we are seeking contributions that use emerging constrains to improve the ability to quantify respiration and photosynthesis processes, transpiration and water use efficiency, at scales from leaf to ecosystem and global. Particularly welcome are studies reporting advancements and new developments in CO2 and evapotranspiration flux partitioning from eddy covariance data, the use of carbonyl sulfide, stable isotopes approaches, with a special attention on sun-induced fluorescence, whose studies at various scales have flourished in the last years, addressing a large panel of fundamental challenges. The assessment of photosynthesis from space-based measurements of fluorescence will also be the focus of the FLEX mission, currently under implementation by the European Space Agency. This session welcomes presentations contributing to a better knowledge on vegetation fluorescence, including its measurement, modelling, interpretation, new instruments and applications from local to global scales. Modelling studies which enhance our fundamental understanding of ecosystem-atmosphere CO2 exchange at global scale or make use of these emerging new constraints in data assimilation schemes are also welcome.

Convener: Georg Wohlfahrt | Co-conveners: Timothy Hilton, Mirco Migliavacca, Karolina Sakowska, Fabienne Maignan, Roberto Colombo, Yves Goulas, Yongguang Zhang
| Wed, 10 Apr, 08:30–12:30
Room L2
| Attendance Wed, 10 Apr, 14:00–15:45
Hall A

Attendance time: Wednesday, 10 April 2019, 14:00–15:45 | Hall A

A.403 |
Oscar Perez-Priego, Gabriel katul, Markus Reichstein, Tarek S. El-Madany, Bernhard Ahrens, Arnaud Carrara, Todd .M Scanlon, and Mirco Migliavacca
A.404 |
Eugénie Paul-Limoges, Sebastian Wolf, Erfan Haghighi, Fabian Schneider, Marcos Longo, Paul Moorcroft, Mana Gharun, and Alexander Damm
A.405 |
Leonardo Montagnani, Daniel Willeit, Massimo Tagliavini, Georg Wohlfahrt, and Damiano Zanotelli
A.406 |
Jonathan D. Müller, Yakir Preisler, Eyal Rotenberg, and Dan Yakir
A.407 |
Timothy Hilton, Mary Whelan, Travis O'Brien, Joseph Berry, and J. Elliott Campbell
A.408 |
Georg Wohlfahrt, Albin Hammerle, Helen Ward, Martin Graus, Felix Spielmann, Thomas Karl, and Mathias Rotach
A.409 |
Felix M. Spielmann, Florian Kitz, Albin Hammerle, Katharina Gerdel, and Georg Wohlfahrt
A.410 |
Katharina Gerdel, Rafael Stern, Madi Amer, Albin Hammerle, Felix M. Spielmann, Eyal Rotenberg, Fedor Tatarinov, Georg Wohlfahrt, Dan Yakir, and Efrat Schwartz
A.411 |
Steven van Heuven, Linda Kooijmans, Andrea Scifo, Bert Scheeren, Maarten Krol, and Huilin Chen
A.412 |
Karolina Sakowska, Albin Hammerle, Felix Spielmann, Arnaud Carrara, Tarek S. El-Madany, Javier Pacheco-Labrador, David Martini, Gerardo Moreno, Tommaso Julitta, Andreas Burkart, María Pilar Martín, Rosario González-Cascón, Oscar Pérez-Priego, Markus Reichstein, Mirco Migliavacca, and Georg Wohlfahrt
A.414 |
Ten years of carbon and water fluxes in central Australia: constraints to ecosystem photosynthesis, respiration and decomposition across climate extremes
James Cleverly, Derek Eamus, Tonantzin Taran, Rachael H Nolan, and Belinda Medlyn
A.415 |
Anne Klosterhalfen, Arnold F. Moene, Marius Schmidt, Todd M. Scanlon, Harry Vereecken, and Alexander Graf
A.416 |
Álvaro Moreno Martínez, Emiliano Díaz, Adrian Pérez Suay, Jose Adsuara, Valero Laparra, María Piles, Jordi Muñoz Marí, Steven W Running, and Gustau Camps Valls
A.417 |
Boaz Hilman, Tal Weiner, Tom Haran, and Alon Angert
A.418 |
Jongmin Kim, Youngryel Ryu, Benjamin Dechant, Hojin Lee, Hyun Seok Kim, Joseph A. Berry, and Ari Kornfeld
A.419 |
LASVEG: A combined airborne instrumental platform for simultaneous measurements of laser-induced fluorescence, SIF, visible reflectance and vertical structure of the canopy
Abderrahmane Ounis, Henri Salvador, Hamza Kamal El Idrissi, Olivier Bousquet, Ismael Moya, and Yves Goulas
A.420 |
Cédric Bacour, Fabienne Maignan, Natasha MacBean, Albert Porcar-Castell, Jaume Flexas, Christian Frankenberg, Nicolas Vuichard, Philippe Peylin, Frédéric Chevallier, and Vladislav Bastrikov
A.421 |
Liesbeth Florentie, Wouter Peters, Gerbrand Koren, Erik van Schaik, Folkert Boersma, and Maarten Krol
A.422 |
Paul Naethe, Andreas Burkart, Tommaso Julitta, Laura Verena Junker, Axel Knaps, Francois Jonard, Daniela Lud, and Uwe Rascher
A.423 |
Veronica Sobejano Paz, Teis Nørgaard Mikkelsen, Mark Johnson, Xingguo Mo, Laura Morillas, Suxia Liu, Liang Shen, and Monica Garcia
A.424 |
Amnon Cochavi, Madi Amer, Rafael Stern, fedor tatrinov, and Dan Yakir