Using a global flux network fluxnet to study the breathing of the terrestrial biosphere
Download
1 / 43

Using a Global Flux Network—FLUXNET— to Study the Breathing of the Terrestrial Biosphere - PowerPoint PPT Presentation


  • 100 Views
  • Uploaded on

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

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Using a Global Flux Network—FLUXNET— to Study the Breathing of the Terrestrial Biosphere' - manny


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
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 Breathing of the Terrestrial Biosphere

  • 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


Network of Regional Flux Breathing of the Terrestrial BiosphereNetworks


Fluxnet from sea to shining sea 500 sites circa 2009
FLUXNET: From Sea to Shining Sea Breathing of the Terrestrial Biosphere500+ Sites, circa 2009


Eddy Covariance Technique Breathing of the Terrestrial Biosphere

  • Direct

  • In situ

  • Quasi-Continuous

  • Extended Footprint


Fluxnet database
FLUXNET Breathing of the Terrestrial BiosphereDataBase

  • 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


Standard Processing Procedure Breathing of the Terrestrial Biosphere

Vs non-standard, but Expert Based


Results and Discussion Breathing of the Terrestrial Biosphere


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 RepresentativenessCovers Climate Space Well

Can we Integrate Fluxes across Climate Space,

Rather than Cartesian Space?


Apply bayes theorem to fluxnet
Apply RepresentativenessBayes 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


Probability Distribution of Published NEE Measurements, Integrated Annually

Baldocchi, Austral J Botany, 2008


Updated PDF with 164 extra site-years Integrated Annually

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


Upscaling Integrated Annually 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


How many Towers are needed to estimate mean NEE, Integrated Annually

And assess Interannual Variability, at the Global Scale?

We Need about 75 towers to produce robust Statistics


Little Change in Integrated AnnuallyAbiotic Drivers--annual Rg, ppt --across Network


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

across the Global Network


Interannual Integrated Annually Variability in GPP is small, too,

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


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


Does Net Ecosystem Carbon Exchange Scale with Photosynthesis?

Ecosystems with greatest GPP don’t necessarily experience greatest NEE

Baldocchi, Austral J Botany, 2008


Ecosystem Respiration Scales Tightly with Ecosystem Photosynthesis,

But Is with Offset by Disturbance

Baldocchi, Austral J Botany, 2008


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

Data of Wofsy, Munger, Goulden, et al.


Interannual Variation and Long Term Trends Photosynthesis,

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

Urbanski et al 2007 JGR


Interannual Variations in Photosynthesis and Respiration are Coupled

Baldocchi, Austral J Botany, 2008


What happens to the grass
What Happens to the Grass? Coupled

June

October


Photodegradation is a new and emerging process affecting c cycle in semi arid grasslands
PhotoDegradation Coupled 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 Coupled: A Process Not in Coupled Carbon-Climate Models

Baldocchi, Ma, Rutledge, unpublished


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 Been



Net Ecosystem Carbon Exchange Scales with Length of Growing Season

Baldocchi, Austral J Botany, 2008


Soil Temperature: Season

An Objective Indicator of Phenology??

Data of Pilegaard et al.


Soil Temperature: Season

An Objective Measure of Phenology, part 2

Baldocchi et al. Int J. Biomet, 2005



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 Phenology NetworkFluxes with Remote Sensing


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 to Daily C Flux Integrals?

spring

summer

autumn

winter

Xiao et al. 2008, AgForMet


Conclusions
Conclusions to Daily C Flux Integrals?

  • 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 to Daily C Flux Integrals?

  • NSF, Research Coordinated Networks

  • Microsoft, Regional Networks, ILEAPS

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


ANOVA analysis of the annual sums to Daily C Flux Integrals?

A. Richardson & D. Baldocchi, unpublished


ad