FLUXNET, Status and Future

Dennis BaldocchiDeb AgarwalDario Papale

NACP/AmeriFlux: New Orleans, LA, Feb 2011

Outline

• Overview, Status and Sustenance, Baldocchi• Data System, Project Management, Agarwal• Value-Added Products, Papale

– Gap-Filling, Flux Partitioning

remote sensingof CO2

Tem

pora

l sca

le

Spatial scale [km]

hour

day

week

month

year

decade

century

local 0.1 1 10 100 1000 10 000 global

forestinventory

plot

Countries EUplot/site

talltowerobser-

vatories

Forest/soil inventories

Eddycovariance

towers

Landsurface remote sensing

Developing a System that is Everywhere, All of the Time

Credit: Markus Reichstein, MPI

Challenges

• To Sustain and Grow the Network that ask and answer Network-Scale Questions– To sample representative Climates and Biomes– To sample representative Disturbance Classes– Detect trends in Fluxes as Climate and Land Use Changes– Validate and Parameterize New Generation of Land

Surface-Atmosphere Exchange Models– Serve as Critical Partner in Machine Learning Approaches

to Flux Upscaling with Satellite Remote Sensing

Status of Global Network, 500+ Sites

Being Registered Does not mean Active or Contributing Data

Growth in Africa, Australia and Asia, Sustenance in Brazil and EuropeDecline in Canada and USVoids in India and Latin America

Many Towers are Not Active, nor Submitting data

FLUXNET Data Archive

Year

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

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Important to Sustain Networks Because Big Science Questions Being Answered by Flux Networks

• What is Global GPP?– 123 +/- 8 PgC/ y, Beer et al, Science

• What is Global ET?– 65,000 km3/y, Jung et al. 2010, Nature

• What is Global Year to Year Variability in GPP and NEE?• What Emergent Scale Properties arise at the Ecosystem

Scale?– Rain-induced respiration Pulses, modulated by photodegradation– Diffuse Light Enhances LUE– Q10 are static and Respiration Decrease with Heat and Drought

Big Network Issues Facing Flux Networks in 2011

• How can we Sustain the Network?• How many Stations are Enough?• Where do we need new Stations?• How can we encourage Scientists to

Participate, submit data and Open the Data to the Wider Science Community, with Benefits to ALL?

How Many Towers are Needed to Yield Stable Network Statistics?

Is this Sample, Statistically Representative of a Biome, Continent or Globe?

FLUXNET database, means +/- 95% C.I.

Year

1996 1998 2000 2002 2004 2006

C F

lux,

gC

m-2 y-1

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GPPReco

Year

1996 1998 2000 2002 2004 2006

C F

lux,

gC

m-2 y-1

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-400

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-100

0

Ne

What is Interannual Variability of Fluxes, sampled with the Network and Detection Limit?Can We ask this Question with a Sparse Network, if the Representativeness of each Tower is

Larger than its Geographical Domain?

This Analysis Would Suggest Global Metabolism is Invariant with Time, like the Solar Constant

Increasing the Size of the Network Reduces the Sampling Error, but in an Asymptotic Manner

Limit in the Precision of NEE Change that can be detected if Upscaled Globally:+/- 20 gC m-2 y-1 ~ 2 PgC/y = 2 1015 gC/y

Can We Truly Detect Year-Year Variations in Fluxes with a Sparse Network?

Errors that sound Small at one scale may be Huge at another..

FLUXNET Database

GPP (gC m-2 y-1)

0 1000 2000 3000 4000

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FLUXNET (254 sites-years), <GPP> = 1033 gC m-2 y-1 Cartesian-Gridded, <GPP> =1139 g C m-2 y-1

Area-Weighted, <GPP> = 1281 gC m-2 y-1

FLUXNET Over represents GPP in Temperate, Mid-Productive Ecosystems; Under-represents GPP in Semi-Arid, low-productive and

Tropical, High Productive Regions

FLUXNET Database

NEE (gC m-2 y-1)

-1400 -1200 -1000 -800 -600 -400 -200 0 200 400 600

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FLUXNETGlobal Map

NEE, FLUXNET = -225 gC m-2 y-1

NEE, globally-integrated, area-wt = -129 gC m-2 y-1

Pros and Cons of Extracting Global Information from a Sparse Network

Flux Networks, Alone, May Not be Able to Answer Important Global Questions

But Flux Networks, In Partnership with Satellite Remote Sensing and New Generation of Machine Learning Algorithms May..

Path to Rich Future of New Scale Emergent Science

Flux Maps of Xiao et al. 2010

Regional Maps for Carbon Markets

Disturbances

Climate Anomalies

Jung et al. 2010 Nature

Evaluation of upscaled global Evapotranspiration

(a) Map of mean Evapotranspiration from 1982-2008

(b) Predicted vs. Observed ET at FLUXNET sites (10-fold cross-validation from MTE training)

(c) Corroboration aganist river catchment water balances

(d) Comparison against GSWP-2 land surface model ensemble (16 models) stratified according to bioclimatic zones

Community Building/OutReach

Newsletter: FluxLetter

Young Scientist Forums

WorkshopsLa Thuile, 2007Asilomar, 2009Berkeley, 2011

FLUXNET and Remote Sensing Open Workshop: Towards Upscaling Flux Information from Towers to the Globe

• June 7-9, 2011, Berkeley, CA• Open Registration, but limited to 150 total..• To learn more about the workshop and to register,

visit:• http://nature.berkeley.edu/biometlab/fluxnet2011/fluxwkshp.html

• Registration/Lunches/Coffee are free• There are limited travel funds available for graduate

students, postdocs and workshop speakers.

Highlights/ Successes• Papers in Science and Nature

– Beer et al; Mahecha et al; Jung et al. • Explosion of Synthesis Papers• New Generation of Spatial Upscaling Papers

– Xiao et al; Jung et al; Beer et al; Mu et al.• Citation Count is Growing

Concluding Comments• We Must Continue to Work Together to Address Important

and Contemporary Questions Pertaining to Earth System Science and Climate Change

• A Large and Growing Community of Modelers and Synthesis Scientists are Dependent Upon our Data

• Data are Produced with Govt Support, so it is the Ethical Duty

• Protections are in place to protect Data, PIs and Students in the Short Term, 1-2 years

• It should be the obligation of PIs to Release Data Sets in the Long-Run, e.g. Older Datasets, to Advance Science