Ozflux08 meeting

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Ozflux08meeting
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Overview

• Introduction ARC NESS
• Plenary
• OzFlux network updates, research activities,
  science highlights
• Discussion
• Funding
• NCRIS
• AEOS concept
• Opportunities for OzFlux
• Key science questions
• OzFlux issues
• QC, data repository, biomass estimates, soil
  respiration
• 2007 conference

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OzFlux network
http//www.cmar.csiro.au/ar/lai/ozflux/
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Existing network

• Initiated by CSIRO (Leuning, Finnagan, Cleugh,
  Raupach, etc.) extended by Universities
• Limited capacity
• Adhoc and uncoordinated
• Some sites in under-represented biomes (savanna,
  broadleaf evergreen)

?
?
Preston - Urban
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NCRIS

• To date
• Exposure draft
• Strategic roadmap
• Feedback June 2006
• Discussion paper
• NCRIS 1 of 16 priorities second tier
• Next
• Workshops
• Appoint facilitator for investment
• Further scoping by Sept 2006

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NCRIS

• Opportunities for Ozflux
• Objective Develop Australias research
  capabilities in areas that support world-class
  research and contribute to achieving national
  policy goals including environmental
  sustainability
• Scope
• Identified the AEON concept as having some
  similarities with TERN
• 8.3 recognise that there needs to be debate
  about whether it is appropriate of viable to
  include atmospheric fluxes and biogeochemical
  cycles
• Appear to be continually marginalised
• We need to argue that from a sustainability
  approach we can not assess ecosystem function and
  change without C and N etc.
• Science questions
• We need to identify key research questions that
  Ozflux can address

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AEOS An Australian Earth Observing System to
monitor and manage Australias terrestrial water,
ecosystem and climate resources

• Objective
• Rapid delivery of data and products needed to
  wisely and sustainably use our terrestrial
  biosphere resources, and to manage the impacts of
  climate variability and change
• Features
• Enhanced climate observations
• Fluxes, concentrations stores of key entities
• Radiation, wind, water, CO2 and non-CO2 gases,
  aerosols
• Integrate satellite data and models
• spatialisation of in-situ network
• near-real time monitoring marine and
  terrestrial
• Uses
• Real-time environmental monitoring
• National carbon and water budgeting - NRM

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AEOS An Australian Earth Observing System to
monitor and manage Australias terrestrial water,
ecosystem and climate resources
National Observing System

• Terrestrial
• Enhances and integrates current networks
  (Ozflux, BoM)
• New monitoring sites

Space Existing sensors and products New sensors
(AATSR, FLORA)
Networked Data Acquisition and Distribution
Backbone
Operational Integration System
Locally operated nodes Standardised
protocols Fast data transfer
Clients ACCESS WRON
Data Assimilation Centre Data acquisition and
processing Data archiving and distribution Modelli
ng
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Towards a terrestrial observing network in situ
monitoring

• 1. Meteorology
• Wind, RH and T
• Soil moisture and temp.
• 2. Radiation
• Short and long wave
• Downwelling and outgoing
• 3. Flux towers
• Mobile and fixed
• 4. Scalars of interest
• Greenhouse gases
• Dust
• ....

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AEOS Concept Integrated Earth Observation
System for Data Integration Predictive Modeling
Data Model Integration System
Real-time Satellite Observations
Foreign Available near real-time data
sources MODIS, ALOS, ENVISAT, NPOESS
Web-based Data Product Delivery System
New Australian Sensors on Foreign Platforms

• Uses
• Real-time environmental monitoring
• Carbon Budgeting
• National Water Budgeting
• CSIRO Climate
• Flagships

Networked X-Band stations
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Past Proposal for Ozflux

• Proposal was University based Monash Uni
  (Beringer et al.)
• 22 Investigators, 14 Institutions
• ARC funding sought for Universities only through
  LIEF

• 1.41 Million total included 30 University
  contribution
• New network designed to capture geographical and
  ecosystem variability including human disturbed
  landscapes
• Constrained by investigator and institution
  locations and interests

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Opportunities

• Limitations (CSIRO)
• Not core business
• Applications/stakeholder focused
• Constraints in working with Universities ?
• Current Australian Research Council (ARC)
  Networks
• Earth system network (Pitman, et al.)
• Terrestrial node (Beringer, et al.)
• Coordinate larger scale initiatives
• Facilitate interaction and collaboration
  (interagency)
• TWP-ICE (regional flux estimates). Twr clusters,
  aircraft, etc.
• Pending - ARC Centres of excellence
• Eucalyptus! (Adams, Beringer, et al.)
• Climate impacts risks and opportunities (Lynch,
  Beringer, et al.)
• Savanna landscapes (Bowman, Hutley, et al.
• Future - National Collaborative Research
  Infrastructure Strategy
• 100 million per year program
• Ozflux mentioned as priority for building
  capacity
• Cross institutions ?

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Objectives
Vision for a Biosphere Observing Network

• Determine the exchanges of energy, carbon (CO2)
  and water and how these vary spatially and
  temporally in response to environmental changes
  and disturbance.
• Understand the biological and climatic processes
  that control carbon and water exchanges
• Parameterise and evaluate ecosystem, land surface
  and hydrological models.
• Compare NEP from towers inventory and other
  biometric techniques.
• Use the knowledge from objectives 1-4, combined
  with existing land-use, aircraft, satellite,
  atmospheric concentration data and along with
  state-of-the-art data assimilation and multiple
  constraint methods to provide regional and
  national estimates of the carbon and water
  cycling in Australian ecosystems on various time
  scales.
• Build expertise and collaborations in global
  change science

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Research Activities Supported

• Most regional flux networks confined to
  quantification, variability, processes, scaling
  and integration through modelling

Observations Flux towers, aircraft, satellite.
Concentrations (LOFLO). Other trace gases (FTIR).
Land surface, land cover, vegetation properties,
physical and biological variables. Potential
supersites?
Models SVAT, physiological, hydrological,
biogeochemical (isotopes). Net fluxes
(comparisons tower versus accounting). Response
processes Data Assimilation/Fusion Assimilate
diverse information
Ecosystem response to climate and human activities
Carbon and water budgets regionally resolved
(soil water - GEWEX). Model inversions (IPILPS).
Adapted from GCP
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Policy relevance of flux studies

• Disturbance studies Fire, land clearing,
  urbanisation, and grazing
• Greenhouse science Carbon balance, non-CO2
  trace gases, aerosols, Mitigation strategies,
  etc.
• Agricultural studies Wheat, Rice, Cereals,
  Grains and pathogens/disease, biomass energy
  crops
• Hydrological studies - Desertification, Water
  balance, supply, Salinity/Erosion
• Predictive Modelling (earth system, land surface,
  biogeochemical, ecophysiological, hydrological,
  etc.)

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Regional network functions

• Site specific process oriented
• Intra network synthesis climate, substrate, and
  functional type gradients
• Cross network comparisons
• Annual accounting Carbon and water balance

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Enhancing network utility and synergies

• Observational/process focus
• Elevated CO2 studies
• Experimental Warming Studies
• Disturbance studies
• Biosphere-Atmosphere Stable Isotope Studies
• Network scaling (chamber, aircraft, boundary
  layer budgets)
• Non-CO2 trace gasses and aerosols (VOCs, CH4,
  N2O, etc.)
• Carbon stocks and turnovers Roots, Tubers, and
  Soil Organic Matter studies
• Nutrient cycling
• Biometric/inventory approaches to carbon balance

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• We propose to add seven new long-term flux towers
  to the existing 4-5 to gain a critical mass for a
  nation-wide network. The new sites have been
  chosen to represent major landscape types across
  the country or sites that have been subject to
  human disturbance (land area estimates from
  NLWRA, 2001). These include
• Urban (Melbourne) Monash University. 12.8 of
  native vegetation has been modified by humans
  following European settlement - urbanisation.
• Bluegum plantation forest (W. Australia) UWA.
  Eucalyptus globules plantations now cover more
  than 150,000 Ha in Australia. 
• Native tussock / hummock grassland (Pilbara, WA)
  (UWA). One of the largest of the major vegetation
  groups (1,756,104 km2).
• Upland wet eucalypt forest (Atherton) James
  Cook University. Comprises 30,232km2. Confined
  to the wetter areas or climatic refuges.
• Acacia Woodlands/scrub (Tennant Creek) Northern
  Territory University and University of
  Technology, Sydney. Comprises 560,649 km2.
• Open eucalypt woodland NSW. (Murrumbidgee Basin,
  Kyeamba Creek ) Monash/Melbourne University.
  The Murrumbidgee is now only 14 woody nearly all
  of which is in the hills/mountains. 650mm
  rainfall.
• Agricultural land (WA) Murdoch University.
  982,051 km2 of native vegetation has been
  modified by human practices following European
  settlement, especially agriculture.

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Network site selection

• Aim to
• the range of bioclimates across the continent -
  wet/dry (8 and 10), tropical (4 and 9), semi-arid
  (3), arid (5), temperate (1,6), mediterranean
  (2,7), cool (11)
• major ecosystem types including a range of
  functional groups Evergreen forest (2,4,9,11),
  woodland (5,6), savanna, (8,10), grassland (3,7)
• a range of important anthropogenic landscapes
  (1,2,7) (e.g. cropping, fire, grazing)
• sites important in carbon sequestration
  activities (2,7,8,11)
• an east-west transect from NSW coast inland
  across the Murray Darling region (6,11)
• a north-south transect from Darwin to Alice
  Springs along a rainfall gradient (5,8,10)
• and sites that link with international programs
  (6-GEWEX, 9-Int Canopy Crane Network).

http//www.clw.csiro.au/research/landscapes/intera
ctions/ozflux/monitoringsites/tumbarumba/pictures/
index.html
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Measurements
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Howard Springs
Virginia Park
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PROJECT 3.2 NET ECOSYSTEM EXCHANGE OF CARBON,
HEAT AND WATER IN A TROPICAL RAINFOREST.
Dr Mike Liddell Chemistry DepartmentJames Cook
University CAIRNS
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THE CAPE TRIB FLUX SITE
Satellite ImageryCape Tribulation LANDSAT80m
resolution
ASTER DEM30m resolution
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THE CANOPY CRANE
Dec. 1998

• Liebherr construction crane Height 48.5m
• Complex mesophyll vine forest ? 25m
  canopyPristine lowland rainforest, high species
  diversity ( 79 tree spp. in 1ha)
• Leaf area index 2003 ? 4
• EC flux equipmentmounted at 45m (Campbell
  sonic, LiCOR IRGA)

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RAINFALL
Assoc. Prof. Steve Turton (CRC-TREM, JCU TESAG)
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Other Partners
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OzFlux

• Determine the exchanges of energy, CO2 and water
  and how these vary spatially across Australian
  ecosystems and temporally from hourly to decadal
  scales. Quantify the seasonal and inter-annual
  variability and dynamics due to environmental
  changes (vegetation structure and phenology,
  droughts, heat spells, El Nino, growing season
  length) along with the role of disturbance (fire,
  agriculture and urbanisation).
• Understand the biological climatic processes
  that control carbon and water exchanges
  (including components).
• Parameterise, evaluate and improve models -
  ecosystem, land surface and hydrological.
• Evaluate techniques - NEP from towers with
  inventory and other biometric techniques.
• Estimate the total potential for carbon uptake in
  Australian ecosystems on regional and national
  scales.
• Build expertise and collaborations in global
  change science to meet increasing demand for
  these skills.

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Research Priorities

• We will provide a major contribution to the
  National Research Priority of An environmentally
  sustainable Australia through three priority
  goals.
• 1) Water a critical resource We will assess
  the role of climate variability on water fluxes
  and the impact on water supplies in vegetated
  catchments for an understanding of sustainable
  water management. Impact of salinity on
  ecosystem-atmosphere system will be investigated.
• 2) Reducing and capturing emissions in transport
  and energy generation We will determine the role
  of Australian ecosystems in carbon sequestration
  and their likely response to climate change,
  climate variability and to human and natural
  disturbances.
• 3) Sustainable use of Australias biodiversity
  We will provide a comprehensive understanding of
  the interplay between natural and human systems
  with regard to the provision of ecosystem
  services (water and carbon).

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Policy need for Flux networks
Policymakers Managers
Flux Network
Mitigation
Management
Adaptation
Other research programs
Adapted from US CCRI
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Stakeholders

• Australian and State Governments (including AGO)
• CRC Greenhouse Accounting
• Bureau of Meteorology
• Forest agencies and companies
• Emissions trading industry
• Primary producers (agriculture, pastoralists,
  etc.)
• Land management authorities (water, soil, air)
• Wider scientific community
• Broader public

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Overall Objective To meet the needs of all
Australians for the meteorological information,
understanding and services that are essential for
their safety, security and general well-being and
to ensure that meteorological data and knowledge
are effectively applied to Australias national
and international goals.
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http//ngs.greenhouse.gov.au/index.html

• Goals of the National Greenhouse Strategy
• To limit net greenhouse gas emissions, in
  particular to meet our international commitments.
  
• To foster knowledge and understanding of
  greenhouse issues.
• To lay the foundations for adaptation to climate
  change.
• Reducing emissions of greenhouse gases,
  consistent with the Kyoto Protocol, has been
  identified by governments as the most important
  area for action.

Australian Greenhouse Office
http//www.greenhouse.gov.au/index.html

• Identify the key policy issues in greenhouse
  action
• Reduce the growth in national greenhouse
  emissions
• Improve sustainable energy services
• Improve knowledge base on climate change
• Evaluate and report on Australias progress
  towards the Kyoto target

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• Our mission is to provide research outputs for
  greenhouse emissions accounting at the national
  and project level.
• Ozflux is Policy relevant in
• Quantifying effect of land management practices
• Contribution of non-CO2 gases
• Validation of IPPC or national emission factors
• Biomass for bioenergy
• Multiple constraint models of national carbon
  accounting

http//www.greenhouse.crc.org.au/
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Conclusions

• Need to incorporate human-environment paradigm
• Must be done at regional scales (not just global
  integration)
• Need to enhance network utility
• Need two-way interaction with Stakeholders
• A successful network will be pitched to policy
  makers and managers
• Network is more than just collecting towers

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• What is an isotope? Elements are defined by the
  number of protons (Z) in their nucleus. The mass
  number  (A) of an element is equal to the sum of
  both protons and neutrons (N) in the nucleus,
  or A N ZA single element can have two or more
  mass numbers due to differences in the number of
  neutrons that can occur in the nucleus.  These
  different forms of a single element are called
  isotopes. While protons have a positive charge,
  neutrons have no charge, so the number of
  neutrons does not affect the charge of a
  molecule. Some isotopes are stable, while others
  are radioactive and release particles and energy
  to decay into a more stable form.Elements usually
  have a common isotope that is the form most often
  found in nature. Because carbon, oxygen, and
  hydrogen are the elements that make up all
  organic matter, biologists are often interested
  in the isotopes of these elements.  Each has
  common and rare forms.  For instance, 98.8 of
  carbon atoms contain 6 protons and 6 neutrons
  with a mass number of 12 the notation for this
  form is 12C. 1.1 of carbon has 6 protons and 7
  neutrons, noted as 13C. Similarly, 99.98 of
  hydrogen is found as 1H, but two stable isotopes
  and one radioactive isotope are known. 99.6 of
  oxygen is 16O, in addition there are three stable
  isotopes and five radioactive isotopes. Nitrogen,
  an important plant nutrient, is also of interest
  to biologists. It is found as 99.6 14N and 0.4
  15N.How common are stable isotopes?A brief
  listing of the stable isotopes and their
  abundances for the elements most commonly used in
  global change research would includeElementIsotop
  eAbundance ()Hydrogen1 H99.9852 H0.015Carbon12
  C98.8913 C1.11Nitrogen14 N99.6315 N0.37Oxygen16
  O99.75917 O0.03718 O0.204Sulfur32 S95.0033
  S0.7634 S4.2236 S0.014Strontium84 Sr0.5686
  Sr9.8687 Sr7.0288 Sr82.56Isotopes influence the
  physical and chemical properties of matter. For
  instance, 12CO2 will behave differently than
  13CO2 during certain processes and chemical
  reactions. Light isotopes form weaker chemical
  bonds than heavy isotopes, so light isotopes are
  somewhat more chemically reactive. Molecules
  containing light isotopes also evaporate and
  diffuse more quickly than their heavier
  counterparts. Therefore an evaporating liquid
  will contain more of the light isotope in the gas
  phase, and more of the heavy isotope in the
  liquid phase.Isotopic fractionation occurs when
  isotopes are partitioned differently between two
  phases or two substances.  If we understand the
  processes underlying fractionation, we can use
  isotopes to determine how plants, animals, and
  whole ecosystems function. We can gain
  information from isotopes that naturally occur in
  the environment in studies of natural abundance,
  or we can artificially apply isotopes in high
  concentrations to use them as tracers.

http//basinisotopes.org/basin/tutorial/measuremen
ts.html
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Measuring stable isotopes Isotope ratio mass
spectrometers (IRMS) are instruments that measure
R (the ratio between two isotopes) to obtain d
(the isotope ratio relative to a standard) and
D (discrimination). Substances introduced as
gases are bombarded with electrons to create
ions.  These ions are accelerated through a
vacuum tube and subjected to a magnetic field
that causes ions of different mass to be
deflected at slightly different trajectories.
Detectors (Faraday cups) are precisely placed at
each trajectory to capture ions of each expected
mass. The resulting value is compared to the
value obtained for the standard gas, and used to
calculate d. Click here for more information
about the Stable Isotope Ratio Facility for
Environmental Research (SIRFER) here at the
University of Utah.
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• How does natural variation in stable isotopes
  come about?
• Variations in the abundances of stable isotopes
  among different compounds arise because the
  chemical bonding is stronger in molecules
  containing heavier isotopic forms, making it more
  difficult to break up the molecule in a chemical
  reaction (often termed kinetic fractionation), or
  because of differences in the physical properties
  of molecules containing heavier isotopic forms
  (often termed diffusive and equilibrium
  fractionation).
• With kinetic fractionation, the rate of an
  enzymatic reaction is faster with substrates that
  contain the lighter isotopic form than in
  reactions involving the heavier isotopic form. As
  a consequence, there will be differences in the
  abundances of the stable isotopes between
  substrate and product. Such differences will
  occur unless, of course, all of the substrate
  were consumed, in which case there would be no
  difference in the isotopic composition of
  substrate and product. Expression of a
  significant kinetic fractionation in most
  biological reactions involves substrates at
  branch points in metabolism, such as the initial
  fixation of CO2 in photosynthesis.
• Equilibrium fractionation events reflect the
  observation that during equilibrium reactions,
  such as the equilibration of liquid and gaseous
  water, molecules with the heavier isotopic
  species are typically more abundant in the lower
  energy state phase.
• Diffusive fractionation events reflect the
  observation that heavier isotopic forms diffusive
  more slowly than lighter isotopic forms.
• What is the natural range of isotopic variation
  in nature?
• The natural variations in isotopic abundance can
  be large, including the that found for materials
  frequently of interest in global changes studies
  waters, greenhouse gases, and biological
  materials. As a starting point, note that some
  atmospheric gases, such as CO2, N2, and O2,
  exhibit limited variation, while N2O and CH4
  exhibit wide isotopic variation. The larger
  isotopic ranges in the latter two gases reflects
  both significant isotopic fractionation by
  microbes as well as different biological
  substrates which are used to produce these gases.

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• How are isotopes affected by plant
  processes? Stable isotopes are a useful tool in
  plant physiology and ecology because isotopic
  fractionation occurs during both photosynthesis
  and transpiration - the basic physiological
  processes responsible for plant
  growth. PhotosynthesisPhotosynthesis converts
  CO2 in the atmosphere to carbohydrates, the
  building blocks of plant material.  We can
  consider photosynthesis in two steps 1) CO2
  enters the leaf from the atmosphere and 2) it is
  fixed into carbohydrates in a process known as
  carboxylation.  Isotopic discrimination occurs
  during both stepsIn step 1, CO2 diffuses into
  leaves through adjustable pores on the leaf
  surface, or stomates.  During diffusion,
  fractionation occurs as the heavier 13CO2
  molecules diffuse more slowly. Thus, the air
  outside the leaf is slightly enriched in 13CO2,
  and the air inside the leaf pore space is
  depleted in 13CO2.  The discrimination value for
  diffusion of CO2 is 4.4.In step 2 carboxylation
  occurs, but the details of carboxylation are
  different for two major pathways of
  photosynthesis that are found in plants.  The
  most common pathway is called C3 photosynthesis,
  because the intermediate molecule in the process
  has three carbon atoms. In C3 plants, CO2 binds
  to the enzyme Rubisco (RuBP carboxylase,).  This
  enzyme preferentially binds to 12CO2 if the
  concentration of CO2 is high and many molecules
  are available.  The concentration of CO2 inside
  the leaf (noted as ci) depends on the rate of
  photosynthesis and the opening of the stomatal
  pores, which in turn influences isotopic
  discrimination.  To understand this, consider the
  extreme case of complete closure of the stomates,
  so that no additional CO2 can diffuse into the
  leaf.  In this case all of the CO2 present inside
  the pore space must be used in photosynthesis,
  and Rubisco has no "choice" about whether to bind
  to 12CO2 or 13CO2.  Therefore, discrimination by
  carboxylation is zero.  However, the diffusional
  discrimination value of 4.4 still applies - the
  carbohydrates produced inside this closed leaf
  will carry this signature.  Because d13C of the
  atmosphere is equal to about -8, the plant
  material in this hypothetical case will equal -8
  - 4.4 -12.4.Conversely, consider that the
  stomates are fully open.  In this case ci
  approaches the concentration of CO2 in the
  atmosphere, noted as ca (ci is always lower than
  ca).  The discrimination by diffusion becomes
  insignificant, but carboxylation becomes very
  important.  Rubisco can now "choose" from many
  CO2 molecules, and will preferentially bind to
  12CO2.  The carbohydrates produced by this
  process will carry the signature of the maximum
  discrimination of Rubisco, about 30.  Adding in
  atmospheric d, the biomass be -38.In reality,
  plants fall between these extreme cases of fully
  closed and fully open stomates.  Typical d values
  for C3 plants are -21 to -35.We can predict
  the photosynthetic discrimination of plants
  because the relationship between ci, ca, and
  discrimination has been expressed
  mathematically 13D a (b - a)ci/ca  where D
  is discrimination, a is the diffusional
  discrimination (4.4) and b is the discrimination
  by carboxylation (30).  Thus, the isotopic
  composition of the plant material contains
  information about ci/ca, which is controlled by
  the rate of photosynthesis anddegree of stomatal
  opening, or stomatal conductance.  There is a
  less common, but still important type of
  photosynthesis called C4 photosynthesis, after
  the four carbon intermediate molecule.  This
  pathway arose because Rubisco will bind to oxygen
  as well CO2, especially under high temperatures. 
  This process is called photorespiration, and it
  is undesirable because plants cannot use oxygen
  for photosynthesis, and actually must release CO2
  to remove oxygen from the pathway.  High CO2
  concentrations inhibit photorespiration, and it
  is likely that C3 photosynthesis evolved when the
  CO2 concentration in the atmosphere was much
  higher than it is today. As the concentration in
  the atmosphere dropped and photorespiration
  became more problematic, a new type of
  photosynthesis arose.C4 photosynthesis limits
  photorespiration by separating the site of CO2
  fixation from the leaf pore space, where the
  oxygen concentration is very high. In the cells
  surrounding the pore space (mesophyll cells), CO2
  is accepted not by Rubisco, but by a different
  enzyme called PEP carboxylase that does not bind
  to oxygen.  It is converted to the 4 carbon
  intermediate malate and transported to special
  cells that surround the plant's vascular
  (circulatory) system.  These cells are called
  bundle sheath cells.  In these cells, malate is
  converted back to CO2 and is fixed by Rubisco in
  the C3 photosynthetic pathway.  Because the
  concentration of CO2 in bundle sheath cells is so
  high, photorespiration is minimized.So why don't
  all plants use C4 photosynthesis?  The extra
  steps of fixing, transporting, and re-fixing CO2
  cost energy.  C4 plants are restricted to
  environments and ecosystems where they have some
  competitive advantage over their neighbors by
  expending extra energy on an alternative method
  of photosynthesis.  Because photorespiration is
  dependent on temperature, C4 plants often (but
  not always) occur in warm climates, where up to
  50 of the carbon fixed by C3 plants can be
  wasted as photorespiration. Some ecosystems, such
  as certain grasslands, are dominated by C4
  plants, while others contain only a small
  component of plants using the C4 pathway.Whether
  a plant is a C3 or C4 type is extremely important
  isotopically.  Bundle sheath cells are almost
  impermeable to diffusion, similar to the example
  of closed stomates discussed above.  Recall that
  if all of the available CO2 is fixed by Rubisco
  there cannot be discrimination.  Plants vary in
  their capacity to seal CO2 inside the bundle
  sheath without leakage, which can affect
  discrimination.  This effect as also been
  described mathematically 13D a (b4 - b3f -
  a)ci/ca   This equation is similar to the
  equation given for C3 plants but has some extra
  terms.  b4 is the discrimination of PEP
  carboxylation of 5.7, far lower than the value
  for Rubisco, or b3, of 30.  f is the fraction of
  CO2 that leaks out of the bundle sheath cells
  this value is typically near 0.2.  Thus, we can
  also use isotopic discrimination to gain
  information on ci/ca and the factors that control
  it in C4 plants, which are more enriched in 13C
  than C3 plants. Typical d values for C4 plants
  are -12 to -15.Oxygen isotopes in CO2 are also
  subject to diffusional fractionation, but once
  inside the leaf, oxygen in water can exchange
  readily with oxygen in CO2 due to the presence of
  an enzyme called carbonic anhydrase.  Only about
  1/3 of CO2 that diffuses into a C3 leaf is
  actually fixed in photosynthesis - the remainder
  diffuses back out and influences the oxygen
  isotope composition of atmospheric CO2. We can
  calculate an "apparent" discrimination against
  18O in photosynthesis of C3 plants, which is not
  entirely based on an actual discrimination
  because of the exchange with leaf water 18D
  Ra/RA - 1 â cc(dc - da)/(ca-cc)   where Ra is
  the ratio of 18O/16O in atmospheric CO2, RA is
  the ratio of 18O/16O in the net flux of CO2 into
  the leaf,  and cc is the CO2 concentration in the
  chloroplast (which is generally lower than ci). â
  is average fractionation during diffusion from
  the air into the leaf chloroplast, the site of
  photosynthesis. This is dominated by the
  diffusion from the atmosphere into leaf pore
  space, which is theoretically 8.8 based on the
  differences in diffusivity between C16O2 and
  C18O2. However, there is some influence by other
  fractionation factors such CO2 entering solution,
  so â is more accurately about 7.4.  18D is
  highly variable across a range of ecosystems - it
  can vary from -20 to 32. This is because da and
  dc, the d values for 18O/16O in the atmosphere
  and chloroplast, respectively, are highly
  variable. We will discuss the factors that
  control them in the next sections.ReferencesEhleri
  nger, J.R., T.E. Cerling, M.D. Dearing. 2002.
  Atmospheric CO2 as a global change driver
  influencing plant-animal interactions.
  Integrative and Comparative Biology 42
  424-430.Farquhar, G. D. 1983. On the nature of
  carbon isotope discrimination in C4 species. Aust
  J Plant Physiol 10 205-226.Farquhar, G. D., J.
  R. Ehleringer, and K. T. Hubick. 1989. Carbon
  isotope discrimination and photosynthesis. Annual
  Review of Plant Physiology and Plant Molecular
  Biology 40 503-537.Farquhar, G. D., and J.
  Lloyd. 1993. Carbon and oxygen isotope effects in
  the exchange of carbon dioxide between plants and
  the atmosphere. Pages 47-70 in J. R. Ehleringer,
  A. E. Hall, and G. D. Farquhar, eds. Stable
  isotopes and plant carbon-water relations.
  Academic Press, New York.Farquhar, G. D., J.
  Lloyd, J. A. Taylor, L. B. Flanagan, J. P.
  Syvertsen, K. T. Hubick, S. C. Wong, and J. R.
  Ehleringer. 1993. Vegetation effects on the
  isotope composition of oxygen in atmospheric CO2.
  Nature 363 439-443.Farquhar, G. D., M. H.
  O'Leary, and J. A. Berry. 1982. On the
  relationship between carbon isotope
  discrimination and the intercellular carbon
  dioxide concentration in leaves. Aust J Plant
  Physiol 9 121-137.

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• Transpiration and EvaporationWater that enters an
  ecosystem through rain can leave through several
  mechanisms. It can runoff the surface, flow
  through the soil and enter groundwater, or it can
  evaporate. Soil evaporation is generally confined
  to the first few centimeters of soil however,
  plant roots can reach depths of many meters to
  remove water from far below the surface. This
  water evaporates out of leaves and returns to the
  atmosphere in the process of transpiration.  The
  combination of evaporation from the soil surface
  and transpiration from plant leaves is
  called evapotranspiration.Water may contain
  isotopes of both hydrogen and oxygen - the light
  isotope of hydrogen is 1H (usually abbreviated as
  H) and the heavy stable isotope is 2H
  (abbreviated as D for deuterium).  The light
  isotope of oxygen is 16O, while the most common
  heavy stable isotope is 18O.  Recall that lighter
  isotopes evaporate more quickly than heavier
  ones, so that there is more of heavy isotope in
  the liquid phase and more of the lighter isotope
  in the gas phase.  This is called an equilibrium
  effect.  It can be described by an equilibrium
  fractionation factor, or a a RL/Rv    where
  R is the ratio of the amount heavy isotope/light
  isotope, L refers to the liquid phase, and v
  refers to the vapor phase.As we discussed in the
  section on photosynthesis, light isotopes also
  diffuse more quickly than heavy isotopes.  This
  is called a kinetic effect, and it can be
  described by a kinetic fractionation factor,
  ak ak D/D' g/g'   where D is the diffusion
  coefficient of the light isotope and D' is the
  diffusion coefficient of the heavy isotope (ak
  1.025 for H/D and 1.0285 for 16O/18O).A diffusion
  coefficient is a constant that quantifies
  differences in diffusion rates among various
  molecules.  We can describe differences in
  diffusion rates through any substance, including
  the stomates of plants, so we can also express ak
  as the ratio of the stomatal conductance of a
  light isotope (g)/stomatal conductance of a heavy
  isotope (g').  This will be useful later in our
  calculations. Both equilibrium and kinetic
  effects are involved in transpiration.  Water
  molecules evaporate into the leaf pore space
  from xylem, the conduits that transport water
  from the soil to the leaves, and then diffuse
  into the atmosphere. The rate of plant
  transpiration depends on the stomatal conductance
  and the dryness of the air relative to the leaf
  pore space, as expressed by the difference
  between vapor pressure inside the leaf (ei) and
  outside the leaf (ea) E g(ei - ea)       where
  E is transpiration and g is stomatal
  conductance.   Let us define E as the
  transpiration rate of water containing light
  isotopes only.  We can also describe the
  transpiration rate of water containing heavy
  isotopes E' g'(Rvei-Raea)     where Rv is the
  ratio of the heavy and light isotopes of water
  vapor in the leaf pore space, and Ra is the ratio
  of heavy and light isotopes of water vapor in the
  air outside the leaf. By combining these two
  equations, we can describe the ratio of heavy to
  light isotopes in transpired water (recall that
  ak g/g' and a RL/Rv) E'/E RT (1/ak)
  (RLei/a - Raea)/(ei - ea)   There is no
  fractionation during transport of the water from
  the soil to the leaves.  Therefore RT is the
  isotopic composition of the plant's source of
  water.  It can be measured by sampling the water
  in stem xylem.  If RT is known, we can rearrange
  the equation to predict the enrichment of 18O and
  D that occurs in leavesRL aakRT(ei-ea/ei)
  Ra(ea/ei)    This leaf water is used in
  photosynthesis to build plant tissues therefore
  all plant material carries the isotopic signature
  of the water source in addition to the
  evaporative enrichment influenced by the vapor
  pressure in the air.

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• How are isotopes affected by plant
  processes?Ecosystem carbon balance
  respiration Stable isotopes may be used to
  understand the processes that affect
  photosynthesis on a whole ecosystem scale. Since
  plants preferentially use 12CO2 in
  photosynthesis, the CO2 left behind in the
  atmosphere is enriched in 13CO2. At the same
  time, plants and all other organisms in the
  ecosystem are always respiring, or using oxygen
  and producing CO2 to maintain metabolic
  processes.  It is commonly assumed that there is
  no fractionation during respiration, so the CO2
  that is respired from organisms has the same
  isotope ratio as the live tissue.  Photosynthetic
  discrimination dominates in the daytime, while
  respiration dominates at night - this produces a
  diurnal variation in d13C of ambient CO2.For C3
  plants, respired CO2 is very depleted in 13C,
  with d on the order of -22 to -35.  Because
  respired CO2 and CO2 left behind in atmosphere
  after photosynthesis have different isotope
  ratios, the isotopic composition of CO2 entering
  and leaving ecosystems can provide information on
  the balance of photosynthesis and respiration, so
  that we can better make predictions about how
  each parameter will change in the future. For
  instance, respiration is largely regulated by
  temperature, whereas photosynthesis is affected
  by light, temperature, drought, and many other
  factors.Organisms that live in the soil also
  respire. Soil organisms range from bacteria and
  fungi to fauna such earthworms, nematodes, and
  even mammals. The plant litter that falls on to
  the soil surface is consumed by many types of
  organisms, which release CO2 in the process. The
  chemical components of plant material are not
  consumed at the same rates, as some are more
  difficult to digest than others. These chemical
  substances, which include sugars, lipids, lignin,
  and cellulose, generally have different isotope
  ratios within a single plant.  Therefore the
  carbon isotope ratio of CO2 emitted from the soil
  can be complex, and may change over time.What is
  a Keeling Plot?We can determine the isotope ratio
  of respired CO2 from the soil or from whole
  ecosystems with Keeling plots.  To construct a
  Keeling plot you must capture CO2 samples during
  a period when the CO2 concentration is changing
  over time. At the night when photosynthesis has
  ceased, the CO2 concentration above the soil or
  the plant canopy increases as the ecosystem
  respires. During this time you can plot the
  isotope ratio of sampled CO2 on the y-axis, and
  the inverse of the CO2 concentration, 1/CO2, on
  the x-axis. This should create a straight line
  because of the mixing of respired and atmospheric
  CO2.  If the CO2 concentration is near the
  atmospheric value of 365 ppm, then the sample
  mostly contains atmospheric CO2, and d13C is near
  -8.  When the CO2 concentration rises above the
  atmospheric concentration, it contains a larger
  proportion of respired CO2, which has a more
  negative carbon isotope ratio.The equation for a
  straight line is y intercept slopex     The
  intercept is the value of y when x if zero. The
  intercept of a Keeling plot is the isotope ratio
  of respiration in the absence of dilution by
  atmospheric CO2.  If CO2 is sampled at the soil
  surface, the Keeling intercept is the isotope
  ratio of soil respiration if it's sampled in the
  plant canopy the intercept is the isotope ratio
  of ecosystem respiration.  It is also possible to
  sample CO2 higher in the troposphere, where the
  carbon isotope ratio represents an entire
  region.  A sample Keeling plot is shown here.We
  can also generate Keeling plots for d18O in CO2. 
  We have described the photosynthetic
  discrimination of CO2 with respect to oxygen
  isotopes and the effect of the exchange of oxygen
  with leaf water. Leaf water is highly enriched in
  18O due to equilibrium fractionation in
  evaporation. Water in other plant parts such as
  stems and roots is not enriched, rather it has
  the same isotopic composition of the source of
  water in the soil.  The CO2 that is respired from
  these plant parts will equilibrate with this
  water, and also have the same isotope composition
  as the water source, which is depleted in 18O.
  Soil respired CO2 also equilibrates with soil
  water it is generally affected by the water at
  about 5-15 cm depth above 5 cm CO2 leaves the
  soil too rapidly to exchange with water, and
  below 15 cm isotopic exchange is negated by
  diffusional effects as the CO2 molecules move
  upwards.  At 5 - 15 cm depth, soil water is
  generally depleted in 18O due to the isotopic
  composition of precipitation discussed
  below.Because of the differences in
  discrimination of 18O during photosynthesis and
  respiration, the oxygen isotope information
  contained in CO2 fluxes from ecosystems can be
  used to separate these two components.  The
  differences in oxygen discrimination between
  respiration and photosynthesis are larger than
  the differences in carbon discrimination, which
  are generally quite small are require
  sophisticated instrumentation to detect. 
  However, d18O can be more temporally and
  spatially variable than d13C due to environmental
  influences on precipitation and atmospheric water
  vapor.  The choice of isotope is dependent on the
  ecosystem and the question of interest.ReferencesB
  outton TW. 1996. Stable carbon isotope ratios of
  soil organic matter and their use as indicators
  of vegetation and climate change. in Mass
  Spectrometry of Soils, edited by T.W. Boutton,
  and S. Yamasaki, pp. 47-83, Marcel-Dekker, New
  York.Bowling DR., Tans PP, Monson RK. 2001.
  Partitioning net ecosystem carbon exchange with
  isotopic fluxes of CO2. Global Change Biology 7
  127-145.Flanagan LB, Ehleringer JR. 1998.
  Ecosystem-atmosphere CO2 exchange interpreting
  signals of change using stable isotope ratios.
  TREE 13 (1) 10-14.Keeling CD. 1958. The
  concentration and isotopic abundances of
  atmospheric carbon dioxide in rural areas,
  Geochim Cosmochim Acta. 13 322-334.Keeling
  CD.1961. The concentration and isotopic abundance
  of carbon dioxide in rural and marine air,
  Geochim Cosmochim Acta. 24 277-298.Pataki DE,
  Ehleringer JR, Flanagan LB, Yakir D, Bowling DR,
  Still C, Buchmann N, Kaplan JO, Berry JA. 2003.
  The application and interpretation of Keeling
  plots in terrestrial carbon cycle research.
  Global Biogeochemical Cycles, 17(1).Yakir D,
  Sternberg LL. 2000. The use of stable isotopes to
  study ecosystem gas exchange. Oecologia 123,
  297-311.

47

• Simulated physiological effects on stable isotope
• fractionation can be evaluated at a growing
  number of field
• sites in the BASIN portfolio
• SiB2 captures important diurnal, synoptic,
  seasonal, and
• interannual variations in ?
• Model (with NDVI and weather drivers) can
  extend
• process understanding to regional and global
  scales
• Time-varying regional simulations of ? may
  provide better
• constraints on CO2 inversions
• Uncertainties in all terms must be quantified
  to make
• proper use of isotopic constraint for regional
  mass balance

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http//biocycle.atmos.colostate.edu/html/simple_bi
osphere_model__sib_.html
50
Ameriflux

• Quantify magnitude of net annual CO2 exchange in
  major ecosystem/biome types (natural and managed)
  
• Determine response to changes in environmental
  factors and climate changes on CO2 fluxes
• Provide information on processes controlling CO2
  flux and net ecosystem productivity
• Provide site-specific calibration and
  verification data for process-based CO2 flux
  models
• Address scaling issues (spatial and temporal)
• Quality control and quality assure data
  collection
• Coordinate the news, and exchange CO2 flux data
  ecological data with other carbon flux networks

51
CarboEurope

• The objectives of the CarboEurope cluster are to
  advance the understanding of carbon fixation
  mechanisms and to quantify carbon sources/sinks
  magnitudes of a range of European terrestrial
  ecosystems and how these may be constrained by
  climate variability, availability of nutrients,
  changing rates of nitrogen deposition and
  interaction with management regimes. Research
  focusing on European ecosystem is complemented by
  investigations of the sink strength of Amazon
  forests.

52
AsiaFlux

• The research potential of studies of carbon
  dioxide, water and heat fluxes in Asia is
  highlighted, and the accumulation of results is
  enhanced.
• Collaborative research is improved through
  information interchange, and results are more
  widely disseminated.
• Results can be compared among Asian countries.
  Moreover, it becomes possible to understand the
  carbon, water and heat budgets of various land
  surfaces and ecosystems in the Asian monsoon
  climate, and of those affected by artificial
  activities such as biomass burning.
• Japanese researchers can play an important role
  in flux research in Asia and can help improve
  FLUXNET.

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Fluxnet-Canada

• Use EC to make continuous, multi-year
  measurements of CO2, water, and sensible heat
  fluxes, for mature and disturbed forest and
  peatland ecosystems along an east-west national
  transect that encompasses some of Canada's
  important ecoregions.
• We will (a) examine inter-annual variability (b)
  contribution of different ecosystem (c)
  relationship between NPP and NEP (d)
  parameterise and evaluate ecosystem and land
  surface climate models.
• Characterise relationships between climate
  variables (e.g., mean monthly temperature) and
  NEP including disturbance
• Compare techniques - NEP from towers with
  inventory and other biometric techniques.
• Gain better approximations of potential carbon
  uptake by Canadian forests and wetlands.
• Train highly-qualified personnel, inform
  policy-makers, and increase public understanding
  of C cycling science and issues.

54
KoFlux

• Our study is to measure the energy, water and
  carbon dioxide flux using eddy covariance method
  and to simulate their exchange using dynamic
  global vegetation model in order to understand
  and predict the changing of biosphere-atmosphere
  interactions for a long time period in Asian
  deciduous forest.

55
The Global Carbon Project - Partnerships and
Stakeholders
ESSP
IGBP
IHDP
WCRP
http//www.GlobalCarbonProject.org
56
GCP Research Goal
http//www.GlobalCarbonProject.org
57
The Conceptual Framework
From http//www.GlobalCarbonProject.org
58
GCP Research Goal

• Can not be considered only at global level of
  integration
• Human-environment interaction regionally specific
• Must therefore address regional issues in
  regional networks

http//www.GlobalCarbonProject.org
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CEOP Hydrology Reference Sites Kyeamba Creek,
NSW Australia                                   
                                                  
                  Site Summary The Murrumbidgee
watershed (drainage area about 100,000 km2) lies
in the eastern headwaters of the Murray-Darling
Basin (drainage area about 1,000,000 km2).
Although the basin lies within about 100 km of
Australia's eas coast, it lies to the west of the
coastal divide and drains generally westward.
Most of the catchment is mixed rangeland and
forest, with mean annual precipitation ranging
from over 1000 mm/yr in the east, reducing to 200
mm/yr in the far west. Management of dryland
agriculture, and particularly soil salinity
problems, are major issues in the basin, as
elsewhere in the MDB. There are also irrigation
areas at several points along the river. Kyeamba
Creek (approx. 500 km2), 700 mm/yr rainfall) is
a research catchment within the Murrumbidgee at
which relatively long-term data exist. Kyeamba
Creek is gauged at two locations, hence providing
the opportunity for nested catchment studies.
Various University of Melbourne (UofM) research
projects have installed, in addition to stream
gages and a precipitation gage network, a
transect of 9 soil moisture monitoring sites
across the whole Murrumbidgee, as well as 14
sites within Kyeamba Creek. Microgravity sensors
and piezometers are also installed at these
sites. In addition to the UofM instrumentation,
some research sites run by other groups have
collected various data from shorter periods
across the Murrumbidgee. At present there is a
flux tower at Tumbarumba, approximately 100 km
east of Kyeamba and in a much wetter climate.
There are plans to install a flux tower within
Kyeamba Creek however funding is yet to be
secured. Data Summary Drainage area to outlet
530km2 (Ladysmith), 145km2 (Book Book)Basin
outlet latitude-longitude 35.19S 147.51E
(ladysmith) 35.35S, 147.55E (Book Book)Stream
gauge period of record 1975 to 1986 and
2001-ongoing(Ladysmith) 1985 to present (Book
Book)Precipitation gauges 5 within Kyeamba
(2001-ongoing) BoM station at Wagga Wagga 15km
from Kyeamba Creek (an AMS and AMO site with 30
mm data - i.e. highest level of BoM sites) 30
min. data since late 1990 and daily data from
1900. There are many other daily rain stations
in the areaMicrometeorological data from Wagga
Wagga - incoming shortwave, screen temperature,
specific humidity, wind speed and direction,
sunshine hours, cloud cover. From these data 30
min forcing data for rainfall, incoming
shortwave, temperature, specific humidity and
wind speed have been derived from Jan 2001 -
present (see report below).Turbulent flux
measurements None at present, fluxes tower
planned for 2004, subject to fundingOther
measurements In situ TDR at 9 sites along
transect across the whole Murrumbidgee 14 sites
within the Kyeamba Creek, mobile TDR measurements
for various dates over parts of the Kyeamba
catchment and 10km transects at 3 of the other
locations within the broader Murrumbidgee
network. Reference Richter, H., Western, A.W.
and Chiew, F.H.S. (2003)  Comparisons of soil
moisture simulations from the VB95 land surface
model against observations. Proceedings of the
International Congress on Modelling and
Simulation (MODSIM 2003), Townsville, July 2003,
(ISBN 1-74052-098-X), Volume 1, pp. 160-165.
Siriwardena, L., Chiew, F., Richter, H. and A.W.
Western. 2003. Preparation of a climate data set
for the Murrumbidgee River catchment for land
surface modelling experiments. CRCCH working
document 03/1, 50pp Walker, J, Grayson, R. B.,
Rodell, M Ellet, K., 2003. Gravity changes, soil
moisture and data assimilation. EGS - AGU - EUG
Joint Assembly, Nice, France, April 2003, CDROM
Western, A.W., Richter, H., Chiew, F.H.S.,
Young, R.I., Mills, G., Grayson, R.B., Manton,
M.and T.A. McMahon, 2002. Testing the Australian
Bureau of Meteorology's Land Surface Scheme using
Soil Moisture Observations from the Murrumbidgee
Catchment. Hydrology and Water Resources
Symposium, July, 2002. Contact Information
Rodger Grayson (University of Melbourne)
r.grayson_at_civenv.unimelb.edu.au Jeff Walker
(University of Melbourne) j.walker_at_unimelb.edu.au
Information also available as MS Word PDF
What is this? Candidate Sites Kyeamba Creek
(Australia) Sleeven Polder (Ireland) Walnut Gulch
(US) Igarape Asu (Brazil) Zwalm River
(Belgium) Volta River (Ghana) Wolf Creek
(Canada) Naqu River (China) Submit Your
Site Current Entries Last update Tue Mar 9
020022 2004 EST
63
  
64
Pataki DE, Ehleringer JR, Flanagan LB, Yakir D,
Bowling DR, Still C, Buchmann N, Kaplan J, Berry
JA. 2003. The application and interpretation of
Keeling plots in terrestrial carbon cycle
research. Global Biogeochemical Cycles, 17(1).
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Flanagan LB, Ehleringer JR. 1998.
Ecosystem-atmosphere CO2 exchange interpreting
signals of change using stable isotope ratios.
TREE 13 (1) 10-14.
72
Falge, E. et al. (2002) Seasonality of ecosystem
respiration and gross primary production as
derived from FLUXNET measurements, Agricultural
and Forest Meteorology 113 (2002) 5374
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Science highlights
76
Howard Springs
77
Howard Springs
NEP -2.6 tC.ha-1.year-1
NEP -0.7 tC.ha-1.year-1

• Inter-annual variability
• Year to year variability large and related to
  length and intensity of wet season, which drives
  changes in grass growth
• Separate tree and grass components using neural
  network model.
• Increase in grass growth produces higher fuel
  loads, which are burned in following years.

NBP -1.5 tC.ha-1.yr-1
78
Virginia Park
http//www.clw.csiro.au/research/landscapes/intera
ctions/ozflux/monitoringsites/virginiapark/picture
s/index.html
79
Virginia Park
Howard Springs
LAI 2.3
LAI 1.3
LAI 0.62
LAI 0.3
80
                                                
                               Australian Canopy
Crane (45m) platform, view to the west
                                       
                                               
                   Soil CO2 flux automatic
closed chamber
Daintree Cape Tribulation
81
Drought effects
Summation kgC/Ha/Day 2001 -312002 4 2003
12
82
Wallaby Creek (Maroondah)

• Carbon and water balances of water catchments
• Chronosequence following fire
• Online Jan 2005
• Coupled with dendrochronology and wood quality
  studies

20 year old
80 year old
300 year old
Canopy height 75-80m LAI 1-2 and BA 60 m2
Canopy height 30-50m LAI 2-3 and BA 30 m2
Canopy height 20-30m LAI 3-4 and BA 25 m2
83
Preston (Melbourne)

• Melbourne urban planning scheme
• Influence of housing density and feedbacks to
  local climate