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Applications of eddy covariance measurements, Part 1: Lecture on Analyzing and Interpreting CO 2 Flux Measurements. Dennis Baldocchi ESPM/Ecosystem Science Div. University of California, Berkeley. CarboEurope Summer Course, 2006 Namur, Belgium. Outline. Philosophy/Background Processing

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Applications of eddy covariance measurements, Part 1:Lecture on Analyzing and Interpreting CO2 Flux Measurements

Dennis Baldocchi

ESPM/Ecosystem Science Div.

University of California, Berkeley

CarboEurope Summer Course, 2006

Namur, Belgium


Outline
Outline

  • Philosophy/Background

  • Processing

  • Time Series Analysis

    • Diurnal

    • Seasonal

    • Interannual

  • Flux Partitioning

    • Canopy photosynthesis

    • Ecosystem Respiration

  • Processes

    • Photosynthesis

      • f(T,PAR, LAI, soil moisture)

    • Respiration

      • f(photosynthesis, soil C &N, T, soil moisture, growth)

    • Functional Type

    • Disturbance

  • Space

    • Cross-Site Analyzes


Philosophy background
Philosophy/Background

  • Philosophy

    • What, How, Why, Will be?

  • BioPhysical Processes

    • Meteorology/Microclimate

      • Light, temperature, wind, humidity, pressure

    • Vegetation

      • Structure (height, leaf area index, leaf size)

      • Physiology (photosynthetic capacity, stomatal conductance)

    • Soil

      • Roots

      • Microbes

      • Abiotic conditions (soil moisture, temperature, chemistry, texture)

  • Spatial-Temporal Variability

    • Spatial

      • Vertical (canopy) and Horizontal (footprint, landscape, functional type, disturbance)

    • Temporal

      • Dynamics

      • Diurnal

      • Seasonal

      • Inter-annual



What the Atmosphere Sees

Schulze, 2006 Biogeosciences










CO2 Storage ‘Flux’




Time Series: Spectral Analysis

Baldocchi et al., 2001 AgForMet



Time Series: Interannual Variability

Data of Wofsy, Munger, Goulden, Harvard Univ



Processes
Processes

  • Canopy Photosynthesis

    • Light

    • Temperature

    • Soil Moisture

    • Functional Type

  • Ecosystem Respiration

    • Temperature

    • Soil Moisture

    • Photosynthesis


Concepts:

NEE and Environmental Drivers

From E. Falge


Pulses switches and lags are important too
Pulses, Switches and Lags are Important too!

  • They are Features of Complex Dynamical Systems

  • Biosphere is a Complex Dynamical System

    • Constituent Processes are Non-linear and Experience Non-Gaussian Forcing

    • Possess Scale-Emergent Properties

    • Experiences Variability Across a Spectrum of Time and Space Scales

    • Solutions are sensitive to initial conditions

    • Solutions are path dependent

    • Chaos or Self-Organization can Arise


Light and photosynthesis leaves canopies and emerging processes
Light and Photosynthesis:Leaves, Canopies and Emerging Processes


CO2 uptake-Light Response Curve: Crops

Linear Function and High r2 (~0.90)


CO2 uptake-Light Response Curve: Forest

Function is Non-Linear and Low r2 (~0.50)


Co 2 flux vs sunlight at different lai
CO2 flux vs Sunlight at different LAI

Xu and Baldocchi, 2003, AgForMet



Ac vs Qp: Daily Sums Become Linear!?

Leuning et al. 1995, PCE


Role of Averaging Period:

Hourly vs Daily

Sims et al. AgForMet, 2005


Role of Averaging Period:

Snap Shot vs Daily Integral

Sims et al 2005, AgForMet



Co 2 flux and diffuse radiation
CO2 Flux and Diffuse Radiation

Niyogi et al., GRL 2004


C fluxes and remote sensing npp and ndvi of a grassland
C Fluxes and Remote Sensing: NPP and NDVI of a Grassland

Xu, Gilmanov, Baldocchi



Linking Water and Carbon:

Potential to assess Gc with Remote Sensing

Xu + DDB


Land Surface Water Index (LSWI) plotted with daily NEE for 2004/2005

Land Surface Water Index LSWI = (ρ860 - ρ1640)/(ρ860 + ρ1640)

PRI and NEE

PRI = (r531 - r570) / (r531 + r570)

Falk, Baldocchi, Ma




De-Convolving Soil Respiration 2004/2005

Kuzyakov, 2006


From E. Falge 2004/2005


Deconstructing nep flux partitioning into r eco and gpp
Deconstructing 2004/2005NEP:Flux Partitioning into Recoand GPP

Falge et al

Xu and Baldocchi


Ecosystem respiration
Ecosystem Respiration 2004/2005

Is Q10 Conservative?

Xu + Baldocchi, AgForMet 2003


Environmental controls on respiration
Environmental Controls on Respiration 2004/2005

Xu + Baldocchi, AgForMet 2003


Rains pulse do not have equal impacts
Rains Pulse do not have Equal Impacts 2004/2005

Xu, Baldocchi Agri For Meteorol , 2004




Respiration and photosynthesis
Respiration and Photosynthesis 2004/2005

Tonzi Open areas

Tang, Baldocchi, Xu, Global Change Biology, 2005


Lags and leads in ps and resp diurnal
Lags and Leads in Ps and Resp: Diurnal 2004/2005

Tang et al, Global Change Biology 2005.



What is Wrong with this Picture? 2004/2005

Valentini et al., 2000, Nature





Temperature Acclimation 2004/2005

Falge et al; Baldocchi et al.


Respiration temperature and acclimation
Respiration: Temperature and acclimation 2004/2005

Analyst: Enquist et al. 2003, Nature


Atkin 2004/2005


Spatial gradients nee and length of growing season
Spatial Gradients: 2004/2005NEE and Length of Growing Season


D re vs d gpp
D 2004/2005Re vs DGPP


Soil Temperature: 2004/2005

An Objective Indicator of Phenology??

Data of Pilegaard et al.


Soil Temperature: 2004/2005

An Objective Measure of Phenology, part 2

Data of: ddb, Wofsy, Pilegaard, Curtis, Black, Fuentes, Valentini, Knohl, Yamamoto. Granier, Schmid

Baldocchi et al. Int J. Biomet, in press


Disturbance and Carbon Fluxes 2004/2005

Amiro et al., 2006



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