Objectives:
O1.1: To provide long term data sets of continuous flux measurements of the
main GHG’s: CO2, CH4 and N2O over at least three core sites and a number
of quasi-mobile sites (Table 1)
O1.2: To analyse the regulation and controlling variables- both in time and
space - in GHG emissions from the core sites and the quasi-mobile sites
O1.3: To assess the uncertainty in the estimates obtained by both observations
and models (see also WP4).
In the past, non-CO2 GHG fluxes have been almost exclusively measured using
flux chamber based point measurements. In addition, the inter-annual variability
is so large, that only after several years of measurements all the variance
in the emission pattern is included. To provide correct area based flux estimates,
observations should be able to cope with this temporal and spatial variability.
We wish to address the following questions:
• What is the magnitude and variability of the fluxes of water vapour,
CO2, CH4 and N2O?
• How do changing environmental conditions, land use changes and management
changes affect plant litter quality and quantity, stability and quantity of
newly incorporated carbon in the soil, and stability of older soil organic matter
pools?
• What is the role of ecosystem type, intrinsic land-properties, land
use and land/water management practices and to which driving processes are the
fluxes most sensitive?
• To what extent are the fluxes of water vapour, CO2, CH4 and N2O coupled
and what are the trade-offs between the GHG’s?
• How large is the inter-annual variability?
• How can we improve default emissions factors that represent emissions
from agricultural practices in the Netherlands?
Methodology:
We aim to perform long-term (at least 2-3 years) continuous flux measurements
using techniques that allow both high temporal resolution of the flux data,
and have good intrinsic capabilities of area averaging. Continuous, micrometeorological
observations of the fluxes provide such a tool. Also, stand-scale, process-based
models need to be further developed in order to be able to properly interpret
the data, and to design simple, yet physically based parameterisations for up-scaling
purposes (see Annex 2). This modelling effort will also provide a basis for
the formulation of mitigation strategies. We will establish a common protocol
for quality control and gap filling, based on existing efforts within the CarboEurope-IP.
We will also apply and further develop separation techniques of the net ecosystem
flux into assimilation and respiration (e.g. van Dijk and Dolman, 2004).
Our intention is to apply two micrometeorological approaches and compare these
methods with respect to accuracy and cost-effectiveness: Tuneable diode Laser
techniques (TDL) using eddy-correlation (EC) techniques and Disjunct Eddy Correlation
(DEC) techniques. In the latter case, novel sensors to determine GHG concentrations
will be tested and further developed (See WP5). A network of micrometeorological
stations will be established to cover relevant ecosystems and land use systems
in the Netherlands. If the development of the new GHG sensors is successful,
these will be used in the network as well in order to prove their reliability
and accuracy in a cost-effective future monitoring network.
The measurements will be executed at three CarboEurope main sites, the two sites
related to the manipulation experiment and two agricultural sites at Lutjewad
and Noord-Brabant. Additional observations will be made using 2 quasi-mobile
stations, at sites representing ecosystems or land-use systems in the Netherlands,
which can have a large impact in GHG flux balances in The Netherlands. Selection
criteria will be surface area, size of the carbon pool, and contribution to
the GHG budget, mitigation potential and sensitivity to changes in the environment.
Observations at the sites will last for about two years. After this period,
the stations will be relocated to other sites.
Land use history is an important determinant of the GHG emissions and is often
not explicitly addressed in relating measurements to site-specific characteristics
(Schoorl et al., 2002). Greenhouse gas emissions of agricultural soils are dependent
on soil organic matter, mineralisation and respiration rates and are related
to specific soil characteristics (Denier van der Gon et al., 2000). Therefore,
in this part of the project GHG measurements will be related to site-specific
characteristics and land use histories that allow up-scaling of the measurements
to the regional level (Veldkamp et al., 2001). Soil organic matter properties
such as compositions and age will be linked to GHG production (Keller et al.,
1993).
Chamber measurements are essential, if local spatial variation in GHG emission
is to be understood. However, the extreme spatial and temporal variability with
chamber measurements presents a problem (Van Dijk and Duyzer, 1999). While micrometeorological
techniques can integrate and quantify emissions at the landscape scale they
cannot be used to study this type of small-scale spatial variation. Emission
factors should furthermore be measured over several years to establish the relation
between amount and timing of rainfall, soil moisture and other controlling factors
and inter-annual variability. The contribution of the chamber measurements is
therefore specifically aimed at inter-site comparisons with small scale and
intensive campaigns as well as prolonged monitoring to be able capture a sufficient
number of episodic events.
With a suite of models (Annex 2) we will analyse the driving variables of GHG-emissions
and in combination with the uncertainty estimates of our measurements we will
derive site level estimates of the uncertainty in emission factors.
Objectives:
O2.1: To study the spatial variability in GHG emission and driving factors caused
by small scale variability within a plot scale
O2.2. To improve estimates the (averaged) contribution to the GHG emission.
O2.3: To derive rules for up scaling from the plot to the landscape
O2.4: To determine the role of small scale spatial (and temporal) variability
in driving variables (soil, ecosystem parameters) on ecosystem level emissions
This work-package deals with the variability of fluxes on scales up to one
square kilometre from plot, to field to landscape. There is a need to understand
the causes of this variability in order to be able to generalize the results
of measurements on the plot scale and scale up to the landscape. The focus is
on areas in agricultural areas i.e. arable land and pasture. In this WP we aim
to address the following questions:
• How large is the small-scale variability of GHG fluxes of vegetated
surfaces and what are the main causes for this variability?
• What are the implications of small-scale variability for up-scaling
of small-scale measurements?
• What is the influence of variability in landscape, such as ditches,
pools, hedgerows, field borders etc. on the use of measurements for scaling
to the landscape scale?
• What is the uncertainty in estimates of landscape emissions due to small-scale
variability?
• How well do estimates of the emissions on the field scale based on models/emission
factors compare with measurements of these fluxes?
• How well do the up-scaled results of small-scale measurements of the
emissions match with field scale measurements?
• What is the impact of the highly stochastic nature of N2O emissions
for scaling up and how do they compare with micrometeorological flux measurements?
Methodology:
To address these questions we will use the data collected in WP1 and these will
be supplemented by campaign-based measurements. The sites for these campaigns
will coincide with those from WP1 to assure the best possible efficiency of
the resources available. To investigate the local variability within the field
scale both measurements with small static flux chambers and analysis of soil
samples (such as C:N-ratio, texture, C, N-stable isotopes, bulk density, soil
pH, CEC, etc) will be made at different locations, combined with mapping of
variability of the phreatic surface and soil moisture. The temporal variation
will be investigated using the measurements made by the automatic chambers and
flux towers. This data will allow further application and development of the
(net-flux based) separation methods of assimilation and respiration developed
in WP1. On a landscape scale the spatial variability of soil and landscape will
be characterised and the uncertainty in emission estimates as a consequence
of small-scale variability will be analysed.
Modelling based on soil sampling will be applied to better understand the processes
involved. Scaling up of chamber measurements to the landscape scale will be
done through the improvement of components (transport processes, microbial transformations,
plant-soil interactions) of existing coupled soil water, energy and greenhouse
gas flux numerical simulation models (e.g. VU-PEATLAND, van den Bos, 2003; see
also Langeveld and Leffelaar 2002; Segers and Leffelaar 2001a,b). To validate
the bottom-up estimates of the chamber measurements and soil samples the flux
data of the micrometeorological systems (WP1) will be used. The soil samples
will also be used as a basis for the analysis of uncertainty in emission estimates
as a consequence of small scale variability in landscape, soil, land use (history)
etc. In addition, measurements of emissions from among others ditches including
open water surfaces will be made to investigate variability in emissions due
to these landscape elements. These measurements will also be used to verify
indirect losses of N2O (see WP2). This will result in a characterisation of
spatial variability of soil and landscape.
Objectives:
O3.1: To assess the possibility of water level manipulation as a management
tool for GHG emissions from fen meadows
O3.2: To understand the controlling mechanisms of GHG emissions (CO2, CH4, N2O)
in fen meadow ecosystems
O3.3: To improve estimates of the contribution of these GHG’s to the overall
land use emissions of the Netherlands
We aim to address the following questions:
• What is the variability in the short (1-2 years) and long term in the
exchange processes of water, energy and greenhouse gases (CO2, CH4, en N2O)?
• What is the effect of fertilisation, different groundwater table regimes
and selected animal husbandry management interventions (e.g manure applications)
on GHG emissions?
• What are the opportunities for the usage of wetlands for greenhouse
gas reduction?
Methodology:
Three experimental sites have been identified for WP3 (A) an undisturbed wetland
for more than ten years with high water table and outside agricultural exploitation
(Horstermeer), (B) a site under agricultural exploitation where after one year
the groundwater table will be raised (landscape experiment) and (C) a site under
agricultural exploitation. The latter two sites have been identified in the
Reeuwijk Zuid Holland area. All three sites will be equipped with an eddy correlation
system for C02 measurements. The eddy correlation measurements be performed
following existing Carbo-Europe protocols (e.g. Aubinet et al., 2000). Two roving
TDL Systems (Simpson et al 1999, Grant and Pattey 1999, Scanlon & Keely
2004) will be used for landscape scale measurements of other GHGs (see further
WP5). Driving variables (temperature, humidity, radiation, soil moisture and
temperature etc.) will collected following the CarboEurope protocol.
Spatial variation of GHG emissions within parcel sized areas will be measured
with a vented/closed flux chamber system with a photo-acoustic spectroscopic
infrared gas analyser. The chambers will be used during intensive field campaigns.
Spatial variation in relation to driving variables (in particular groundwater
level) within the landscape will be assessed with measurements at each tower
flux site. All parcel flux measurements will be done in close conjunction with
WP2. This cooperation will also take place for the scaling-up of chamber measurements
to the landscape scale. Through the modelling effort we gain insight in the
possible long-term behaviour of GHG emissions and options for mitigation.
To address the indirect losses of GHG additional measurements will be made of
nutrient concentrations and dissolved organic carbon as well as discharge in
surface- and groundwater by automatic sampling. This will be done in close cooperation
with the assessment of indirect losses in WP5.
Objectives:
O4.1: Compare different methods to estimate ecosystem level greenhouse gas emissions
and evaluate the suitability of these methods for national scale inventories
(Tier 3 method)
O4.3: Quantify the uncertainty in ecosystem level emissions
O4.4: Provide a bottom up estimate of the GHG balance of Dutch ecosystems
We wish to address the following questions:
• What are the currently used up-scaling methods used in GHG emissions,
Tier1/2/3 methods with their sources of uncertainty?
• What is the performance of the models in Annex 2, when tested against
micrometeorological data, and fed with independent estimates of parameters
• Which models need to be included in the suite of models that can provide
region/country wide estimates of the full GHG balance and what is their minimum
level of complexity
• What is the uncertainty related to the structure and process description
of the models (Tier 3) used and what part can be related to parameter uncertainty?
• What is the integrated GHG balance of Dutch ecosystems and what is the
associated uncertainty?
Methodology:
The recent IPCC guidelines for Good Practice indicate the required level of
uncertainty analyses in Tier 3. Overall uncertainty in models can be derived
from two main components: uncertainty in the structure of the model and uncertainty
in the parameter values. The first source of uncertainty is difficult to quantify.
Comparison with observational field data can indicate that either the structure
of the model or the parameter values or both are incorrect. It is therefore
important to test validity of the models.
We will aim to develop a system that uses several specialized models (Annex
2), and do not aim to produce a single modular model that deals with all ecosystems.
Specialized models often better represent crucial elements for a specific land
use type that would be lost in a more general model. Whenever possible we will
compare process descriptions of the model against data. Thus we will use specialized
models for N2O production (INITIATIOR, DNDC), CH4 production (PEATLAND) and
Vegetation Growth models (CENTURY, LPJ) for estimating carbon dynamics of grassland
and forests. Models that predict exchange at the time scale of flux measurements
(typically hourly to daily), such as SWAPS(-C), will be used as a scaling interface
from these short-term measurements to seasonal and annual processes represented
by the other models. In this way, the data use can be optimised to produce the
best set of parameters from a minimum amount of data, collected in this project
as well as related projects (Bsik ME-3: soils and biomass; CarboEurope). In
this work package we focus on ecosystem and regional level, in contrast to the
site level modelling efforts in WP1.
We will determine the structural and process model uncertainty by comparing
the performance of these individual modes against observations at landscape
scale from the micrometeorological flux measurements. Monte Carlo analysis and
sophisticated error propagation methods will be our main tools to determine
parameter uncertainty. In conjunction with ME-2 (Regional Experiment) we will
also assess the uncertainty due to land cover classification by using different
land cover classification products and classes (LGN, IGBP, etc). We will use
the extensive experience on land use classification available within our consortium
(e.g. Veldkamp and Lambin, 2001). We will pay special attention to variability
in soil physical and chemical parameters as these are related to land use history
and previous management. We will try to acquire the most accurate record of
this history for our sites. We will also evaluate the methods with regard to
their data demand and required level of accuracy. We will also investigate the
use of non-process based models such as statistical and neural network models.
Once, we have selected a suite of models we will integrate this with a land
classification scheme and produce a full GHG-balance at the ecosystem level
for at least five years (compatible with a commitment period). This will be
based on spatially explicit approaches. This information will be shared with
ME-3, which is based on soil and biomass inventories.
Objectives:
O5.1: To determine indirect emissions of N2O from ditches and groundwater
O5.2: To develop a low maintenance system for routine measurement of fluxes
of N2O and CH4
O5.4 To develop the use of QCL (quantum cascade laser system)
O5.3: To identify technological innovations that have patent or commercial potential.
In this work package we will develop new methods and techniques that are highly
innovative. Because they carry some risk of failure in their development, these
technologies are not part of any of the standard work packages at the start
of the project. They will only be applied after successful development. However,
because of the potential value of the technologies we wish to invest in their
development. We currently have three technologies to explore: use of isotopes
techniques to measure indirect losses of N2O, development of Disjunct Eddy Correlation
(DEC) methods to measure fluxes of CH4 and N2O and the operational deployment
of a Quantum Cascade laser (QCL) system.
We address the following questions:
• What is the magnitude of the indirect emissions of N2O from ditches
and can we determine these with stable N-isotopes?
• What is the best experimental configuration for a stand-alone Disjunct
Eddy Correlation system for continuous measurement of N2O and CH4 emissions.
• What is the optimum deployment and use of the QCL system to measure
CH4 and N2O simultaneously
Methodology:
Estimations of indirect losses of N2O, particularly from agro-ecosystems, either
through dissolved N2O in drainage water or through NO3 that is subsequently
denitrified into N2O, are based on default emission factors. However, these
default emissions are based on scarce experimental evidence, and actual emissions
may vary several orders of magnitude. Indirect emissions of N2O are expected
to be very specific due to high leaching losses in low and wet areas. A direct
measurement of these indirect losses is needed in order to be able to present
a sound greenhouse gas budget for the Netherlands and to break down emissions
into different sources. Dissolved greenhouse gases, in particular N2O, will
be measured in drainage water on two sites and 15N labelling will be used to
determine the fate of specific sources. Using 15N labelling, nitrogen applied
will be tracked through the system, and indirect and direct losses as well as
immobilization and crop uptake will be quantified over a number of years. Fast
response box measurements will be used to obtain a (limited) number of measured
emission levels from ditches and water bodies close to the experimental fields
(in combination with WP2).
Stand-scale fluxes of water vapour and CO2 will be observed by means of the
eddy correlation technique. Rinne et al. (2001) describe a system where continuous
measurements of concentrations are replaced by fast, grab samples, that are
analysed seperately by a low time response gas chromatograph (DEC). When the
sampling is random, the total sampled structure approaches the powerspectrum
of a continuous system at high frequency, and an accurate measurement of the
flux can be obtained. We will develop such a system for CH4 and N2O measurement
using for instance a photo acoustic gas chromatograph. The system will be initially
tested at the Horstermeer site. When successful it will be deployed at the quasi-mobile
stations.
Arguably, the best available technique at the moment to obtain a hectare averaged
exchange fluxes for an ecosystem, is the eddy covariance technique. For CO2
this is available now for almost a decade and widely applied. Development of
this technique for CH4 and N2O is still ongoing. Tunable diode lasers and Quantum
Cascade laser spectrometers are able to the provide the gas-specific, sensitive
concentration measurements at 5-10Hz needed for this technique. The TDL have
proven to be useful for this application. (Cellier et al, 1998). The QCL lasers
are in theory even better because of their improved thermal stability and level
of lower maintenance needed. The experience with QCL systems however is still
very limited. Within the Netherlands we can use the experience with TDL eddy
correlation measurements obtained in the EU-Greengrass project.
To compare measurements of Greenhouse gases by the participating groups an inter-calibration
will be set-up following CarboEurope protocol.
Objectives:
O6.1: To set up a communication strategy for the overall project for knowledge
transfer and dissemination towards distinct audiences including scientific and
societal stakeholders.
O6.2: To organize and design specific communication in workshops and training
programmes for students and scholars and to write fact – sheets for selected
audiences
O6.3: To set up a website to inform stakeholders and public
O6.4: to track and update the scientific output and collaborative efforts in
the project
O6.5: to communicate on relevant issues with advisory board, scientific steering
committee and stakeholders
Methodology and activities:
Strategy
A communication strategy for the overall project to achieve knowledge transfer
and dissemination to distinct audiences including scientific and societal stakeholders
will be developed in the first year. Communication includes integration of the
results within this project and is directed towards the following audiences:
scientists, general (inter)national public through magazines and journals and
policy makers at local to (supra)national level, enterprises including farmers,
scholars and schools with custom designed materials.
Website
The website is available within 2 months after the start of the project. The
website will include: a news section, (updated) project planning, a database
with all relevant scientific activities in this BSIK project and the location
of all activities, an (updated) database on emissions and concentration of greenhouse
gases and a database of all relevant publications from this BSIK project. The
website will allow visitors to interact with the researchers by means of questions
and answers and discussion. The website will be updated on a regular basis and
include latest news items. The website will be linked with the Bsik website.
Workshops
• Science: participants to the project will actively participate in (inter)national
workshop with presentations, posters and discussion.
• Stakeholder – science interaction: the project will contribute
to an workshop in 2005 bringing together policy makers and societal stakeholders
and scientist on the issues of relevancy of the work to society to be initiated
by the BSIK – Climate directors invited by the Ministry of Agriculture.
• Training: A summer school will be set – up and scientist from
this project will actively contribute
Fact – sheets
All project members will contribute to fact – sheets. The fact –
sheet will follow a standard format and include a section Q&A (questions
and answers) directed towards improving the understanding of the major non –
scientific societal stakeholders and policy makers. Fact – sheets are
available from the project website (starting end 2005)
Scientific publications
During the course of the project a series of scientific manuscripts will be
written and submitted to relevant international high standard scientific journals
such as: We anticipate that over 5 years up to 25 paper will be published in
peer reviewed journals. Additionally papers will be published in books, symposia
proceedings and other scientific literature and papers or contributions (mostly
in Dutch) will be written for general literature and magazines for the general
public and other stakeholders. Posters presented at symposia or otherwise will
be available from the website. All publications will acknowledge the BSIK –
Climate contribution to the research.
Collaborative efforts
The project will attempt to setup collaboration with initiatives such as E –
mission and other initiatives involving schools and young people and with the
organizations involved. The E – mission initiative invites schools and
scholars to participate in a project on measurements of greenhouse gas concentrations
and emission in their school environment en learn more about sources of greenhouse
gases and how to change the source strength. To this end there will be a link
to the integration theme. The success of the collaboration will benefit largely
from the BSIK communication plan. Other initiatives are underway in Carbo –
Europe.