LeafWeb(leafweb.ornl.gov)

• Objectives- Provide plant physiologists and photosynthesis researchers a reliable tool for analyzing leaf gas exchange measurements- Develop a global database of critical leaf biochemical and physiological parameters for ecosystem and land surface models

• Approach - Web-based automated SErvice in Exchange for Data

Sharing (SEEDs)

The most influential data and model in the carbon cycle research

Keeling Curve Farquhar-von Caemmerer-Berry (FvCB) Model

LeafWeb estimates FvCB parameters from leaf gas exchange measurements

InstrumentsLi-Cor 6400 Walz GFS - 3000

Globally, thousands of units are used by plant scientists

Yet data starvation contributes to unsatisfactory terrestrial carbon cycle model performance

Terrestrial Biogeochemistry Models cannot get seasonal cycles of CO2 right (Hoffman et al 2009)

No consistency in terrestrial carbon cycle models (Friedlingstein et al 2006)

LeafWeb strives to connect the two communities

Although the FvCB model was developed 30 years ago, its parameters has not been correctly estimated from measurements because:

• FvCB is a change-point model• FvCB is over-parameterized with respect to

typical A/Ci curves• The FvCB model dictates the order of

photosynthetic limitation states

These facts are considered in LeafWeb

LeafWeb support structure

Theoretical analysis

Numerical solutions

Validation of numerical solutions

Web implementation

Data harvest and managementData synthesis

Forcing SFA Modeling / data assimilation

Forcing SFA MOFLUX

CDIAC

Data flow through LeafWeb

• Data collected from the user- Core variables- Variables to put the leaf in its environment

• User option of Share or not to share data• Graphic capabilities• Results to the user• If the Share option is selected, the data are available to

the general public; graphic function is enabled to the user• If not to share, data and results are not archived, no

graphic function

Future efforts

• Get users to know LeafWeb• Get users to use LeafWeb• Relax data format requirement• Implement C4 photosynthesis program

Comment from Graham Farquhar:

“I am very interested……as are the reviwers”

Comments from anonymous reviewers:

“The methods presented in this manuscript may constitute a very significant advance in the estimation of the parameters of the FvCB model of carbon assimilation, and could be the definitive solution to a longstanding problem. They might be of even broader importance, in the study of change-point models in general. ”

“Given the potential value of this work, and the very real possibility that the authors have achieved a remarkable breakthrough……

A self promotion (for the right cause)

So Use LeafWeb!

Model representation