Using a global flux network fluxnet to study the breathing of the terrestrial biosphere
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Using a Global Flux Network—FLUXNET— to Study the Breathing of the Terrestrial Biosphere. Dennis Baldocchi ESPM/Ecosystem Science Div. University of California, Berkeley Collaborators

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Using a Global Flux Network—FLUXNET— to Study the Breathing of the Terrestrial Biosphere

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Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Using a Global Flux Network—FLUXNET— to Study the Breathing of the Terrestrial Biosphere

Dennis Baldocchi

ESPM/Ecosystem Science Div.

University of California, Berkeley

Collaborators

Rodrigo Vargas, Youngryel Ryu, Markus Reichstein, Dario Papale, Andrew Richardson, Deb Agarwal Catharine van Ingen, Bob Cook and Regional Networks

ILEAPS 2009

Melbourne, Australia


Objectives

Objectives

  • Network Background

  • Statistical Representativeness

    • Global Statistics on NEE, GPP, Reco

    • Network Size

    • Is the Statistical Distribution of Carbon Fluxes Invariant at the Global Scale?

  • Emergent Processes

    • Coupling between Photosynthesis and Respiration

    • PhotoDegradation, a New Process to Consider

    • Fluxes and Phenology

  • Space

    • Regional Flux Maps

    • Phenology Greenwave


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Network of Regional Flux Networks


Fluxnet from sea to shining sea 500 sites circa 2009

FLUXNET: From Sea to Shining Sea500+ Sites, circa 2009


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Eddy Covariance Technique

  • Direct

  • In situ

  • Quasi-Continuous

  • Extended Footprint


Fluxnet database

FLUXNET DataBase

  • Web sites

    • www.fluxnet.ornl.gov/fluxnet/index.cfm

    • www.fluxdata.org

  • QA/QC

    • Data Standardization (names, units)

    • Version Control

  • Derived Flux Quantities

    • Gap-Filling

    • U* corrections for periods of low turbulence

    • Daily, Monthly, Annual Integrals

  • Flux Partitioning

    • Converting NEE into GPP and Reco

  • Compiling Multifaceted Site MetaData

  • Data Distribution

    • Search/Manipulate/Archive


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Standard Processing Procedure

Vs non-standard, but Expert Based


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Results and Discussion


Over arching questions relating to statistical representativeness

Over-Arching Questions relating to Statistical Representativeness

  • As the sparse Network has grown, can it provide a Statistically-Representative sample of NEE, GPP and Reco to infer Global Behavior?, e.g. Polls sample only a small fraction of the population to generate political opinion

  • If mean Solar inputs and Climate conditions are invariant, on an annual and global basis,are NEE, GPP and Reco constant, too?; e.g. global GPP scales with solar radiation which is constant

  • Can Processes derived from a Sparse-Network be Upscaled with Remote Sensing and Climate Maps?; e.g. We don’t need to be everywhere all the time; We can use Bayes Theorem and climate records to upscale.


Global distribution of flux towers covers climate space well

Global distribution of Flux Towers Covers Climate Space Well

Can we Integrate Fluxes across Climate Space,

Rather than Cartesian Space?


Apply bayes theorem to fluxnet

Apply Bayes Theorem to FLUXNET?

p(flux) from FLUXNET

p(climate|flux) prior from FLUXNET

p(climate) from climate database

Estimate Global flux by Integrating p(Flux|climate) across

Globally-gridded Climate space


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Probability Distribution of Published NEE Measurements, Integrated Annually

Baldocchi, Austral J Botany, 2008


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Updated PDF with 164 extra site-years

yields an insignificant change in the mean (P= 0.68)


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Upscaling Flux Data with Remote Sensing Data

Published, Global: -182 gC m-2 y-1

Map, US: -189 gC m-2 y-1

Xiao and Baldocchi, unpublished


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

How many Towers are needed to estimate mean NEE,

And assess Interannual Variability, at the Global Scale?

We Need about 75 towers to produce robust Statistics


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Little Change in Abiotic Drivers--annual Rg, ppt --across Network


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Interannual Variability in NEE is small (between -220 to -243 gC m-2 y-1)

across the Global Network


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Interannual Variability in GPP is small, too,

across the Global Network (1103 to 1162 gC m-2 y-1)


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Potential and Real Rates of Gross Carbon Uptake by Vegetation:

Most Locations Never Reach Upper Potential

GPP at 2% efficiency and 365 day Growing Season

tropics

GPP at 2% efficiency and 182.5 day Growing Season

FLUXNET 2007 Database


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Does Net Ecosystem Carbon Exchange Scale with Photosynthesis?

Ecosystems with greatest GPP don’t necessarily experience greatest NEE

Baldocchi, Austral J Botany, 2008


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Ecosystem Respiration Scales Tightly with Ecosystem Photosynthesis,

But Is with Offset by Disturbance

Baldocchi, Austral J Botany, 2008


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Decadal Plus Time Series of NEE:Flux version of the Keeling’s Mauna Loa Graph

Data of Wofsy, Munger, Goulden, et al.


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Interannual Variation and Long Term Trends

in Net Ecosystem Carbon Exchange (FN), Photosynthesis (FA) and Respiration (FR)

Urbanski et al 2007 JGR


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Interannual Variations in Photosynthesis and Respiration are Coupled

Baldocchi, Austral J Botany, 2008


What happens to the grass

What Happens to the Grass?

June

October


Photodegradation is a new and emerging process affecting c cycle in semi arid grasslands

PhotoDegradation is a New and Emerging Process Affecting C Cycle in Semi-arid Grasslands

Baldocchi and Ma, unpublished


Photodegradation a process not in coupled carbon climate models

PhotoDegradation: A Process Not in Coupled Carbon-Climate Models

Baldocchi, Ma, Rutledge, unpublished


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

More Carbon is Lost with Rain Pulse on Dry Matter that has Been PhotoDegraded than Dry Matter in the Shade

Xu, Baldocchi, Tang, 2004

Global Biogeochem Cycles


Phenology

Phenology


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Seasonality in GPP follows NDVI and Defines Growing Season

Ryu et al. in prep


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Net Ecosystem Carbon Exchange Scales with Length of Growing Season

Baldocchi, Austral J Botany, 2008


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Soil Temperature:

An Objective Indicator of Phenology??

Data of Pilegaard et al.


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Soil Temperature:

An Objective Measure of Phenology, part 2

Baldocchi et al. Int J. Biomet, 2005


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Spatialize Phenology with Transformation Using Climate Map

Baldocchi, unpublished


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Flux Based Phenology Patterns with Match well with data from Phenology Network

White, Baldocchi and Schwartz, unpublished


Spatial variations in c fluxes with remote sensing

Spatial Variations in C Fluxes with Remote Sensing


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

Do Snap-Shot C Fluxes, inferred from Remote Sensing, Relate to Daily C Flux Integrals?

Sims et al 2005 AgForMet


Spatial variations in c fluxes

Spatial Variations in C Fluxes

spring

summer

autumn

winter

Xiao et al. 2008, AgForMet


Conclusions

Conclusions

  • A sparse Global Network of Flux Towers produces statistically robust findings that are representative of broad climate and ecological zones that may integrated to validate models at grid/landscape/regional scales

  • Any Statistical Scaling Approach based on Climate must consider Disturbance and Stand Age, too.

  • A global Network of Flux Towers is discovering a number of emergent scale processes relating to the controls in inter-annual variability, controls by light, and phenology


Acknowledgments

Acknowledgments

  • NSF, Research Coordinated Networks

  • Microsoft, Regional Networks, ILEAPS

  • World-wide Collection of Collaborators and Colleagues, Technicians, Postdocs and Students


Using a global flux network fluxnet to study the breathing of the terrestrial biosphere

ANOVA analysis of the annual sums

A. Richardson & D. Baldocchi, unpublished


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