Proposal 2011

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Integrated Carbon Observing System (ICOS)

Proposal for the Dutch contribution to ICOS-EU: The ICOS-NL Integrated Data Interpretation Center

ICOS is a European Infrastructure dedicated to high precision monitoring of greenhouse gas balances. It will provide policy makers and scientists with estimates of the fluxes of carbon dioxide, methane, and nitrous oxide, and how these fluxes evolve due to policy measures, climate change, and changes in land use. Dedicated ICOS-EU centers were recently established to provide services for atmospheric greenhouse gas monitoring (France, Finland, Germany), ecosystem monitoring (Italy), and fossil fuel emissions monitoring (Germany). The Netherlands will contribute an infrastructure for the quantitative and objective interpretation of ICOS-EU observations. We propose to establish a new ICOS-NL “Integrated Data Interpretation Center” to provide the required expertise on high-performance computing, mathematical algorithms, ecosystem-agriculture-climate modeling and model-data fusion techniques. Expertise, research capacity, as well as policy and science relevant greenhouse balance products will be the core services to Europe. Ongoing cutting-edge Dutch research in these fields will support the tasks of the center. This facility will be unique in Europe.

The mission of ICOS-EU
ICOS-EU aims to provide the long-term observations required to understand the present state and to predict the future state of the global carbon cycle and greenhouse gas emissions. The ongoing and planned activities within ICOS-EU assess the effectiveness of carbon sequestration and greenhouse gases emission reduction activities on the global atmospheric composition. The ICOS activities are urgently required, both from a global perspective (possible degradation of high-latitude peat soils, and the impact of tropical deforestation) and from regional perspectives (verification of national bottom-up emission inventories and estimates of greenhouse gas exchanges with various ecosystem types).
In October 2006, the European Strategy Forum for Research Infrastructures (ESFRI) roadmap identified the ICOS Research Infrastructure as one of the vital new European Research Infrastructures for the next 20 years. ICOS was initiated by successful developments of the research tools and capacity building at the European level necessary to quantify and understand the sources and sinks of greenhouse gases at regional and continental scales, like CARBOEUROPE, NITROEUROPE, and CARBOOCEAN. ICOS contributes to the implementation of the Integrated Global Carbon Observation System (IGCO).

The importance of greenhouse gas flux estimates
Fossil fuel combustion, intensive farming, cement production, waste management, and rice production are examples of omnipresent human activities that lead to enhanced concentrations of greenhouse gases in our atmosphere. Greenhouse gas concentrations will continue to increase in the 21st century and the cumulative effect on the radiative balance of the Earth compared to pre-industrial times will by 2100 be more than doubled compared to the current situation, if no effective measures are taken.
The resulting climate change due to the perturbed radiation balance will feed back on greenhouse gas exchanges with the biosphere and oceans. Examples are enhanced growth of forests due to fertilization, peat degradation due to melting permafrost, and reduced ocean CO2 uptake due to acidification. Monitoring the exchange (“fluxes”) is therefore important and will lead to an improved understanding of the feedback processes.
For reporting purposes, policy makers require estimates of greenhouse emissions on country level scale. While the emissions of emissions stacks can be adequately monitored, large challenges exist in estimating more diffuse exchange fluxes, like the exchange of CO2 with natural or perturbed ecosystems.

How to obtain flux estimates?
Reliable greenhouse gas flux estimates can only be obtained by a combination of measurements and modeling. Measurements of atmospheric concentrations, the isotopic composition of gases, and of the surface exchange at ecosystem scales provide constraints for process-based models to predict global to regional carbon exchange. For more than a decade Dutch scientists play a key role in performing both high quality measurements (e.g. the CESAR infrastructure at Cabauw, http://www.cesar-observatory.nl/) and in the interpretation of these measurements by means of merging data with process models (e.g http://www.carbontracker.eu). Also in the initiation of new space-based sensors and the interpretation of the new satellite measurements of greenhouse gas columns, Dutch scientists and industry (Dutch Space) play a leading role.

The Role of the Netherlands
Within Europe, the new ICOS-NL Integrated Data Interpretation Center will become responsible for the measurement-model merger that is needed for an objective, quantitative EU wide greenhouse gas balance assessment. This role can be fulfilled particularly well by the Netherlands as national research themes have covered the most important components needed for such an assessment. This includes (a) performing atmospheric concentration and local flux measurements with state-of-the art instruments. (b) Simulating transport and mixing of trace gases in the atmosphere, and (c) modeling ecosystem health and functioning. With respect to (a), highest quality atmospheric and ecosystem measurements are currently taken at several locations in the Netherlands. Within ICOS-EU, Dutch scientists will continue to perform these measurements according to the highest standards prescribed by ICOS-EU and thereby support the model-data fusion. For aspect (b) Dutch scientists play a key role in atmospheric transport model development, and the Dutch school of planetary boundary layer research developed through several institutes (KNMI, WU, IMAU, Delft) is world-renowned since the 1980’s. For (c), the prediction of concentrations of greenhouse gas concentrations in e.g. 2100 requires knowledge about ecosystem behavior and the atmospheric oxidation capacity. This knowledge in currently integrated by Dutch scientists in the new climate model EC-EARTH.

Data-assimilation
Data-model fusion is commonly referred to as data-assimilation. This technique forms the heart of the daily weather forecast, in which millions of measurements are blended with a physics-based prediction of the atmospheric state. The result is a highly detailed estimate of the atmospheric state (such as temperature, humidity, and pressure) that is consistent with all observations and with the process knowledge represented in the weather model.
A similar estimation method of greenhouse gas fluxes based on atmospheric observations and models is a rapidly evolving scientific discipline with large potential for Netherlands scientific community. It combines high-performance scientific computing, clever data-assimilation algorithms, and innovative modeling techniques. Data-assimilation can also evaluate the potential of new measurement techniques that can provide unique information about the greenhouse gas exchange processes. For instance, measurements of the isotopes 13CO2 and 14CO2 provide specific information about carbon dioxide exchange from crops and from fossil fuel sources. However, correct interpretation of such unique measurements requires new modeling techniques to capture the processes that drive the CO2 exchange.

Unique opportunity
ICOS-NL takes on the unique opportunity to combine existing expertise to assess high-resolution greenhouse gas fluxes from a multitude of high-quality atmospheric measurements. At the scale of the Netherlands, experts in (isotope) measurement techniques, modeling and data-assimilation already work closely together to fulfill the ICOS-EU goal on high spatial scales: the understanding of the current greenhouse gas balance and the prediction of its future evolution.

Main Text:

The Challenge:

The fourth assessment report of the International Panel on Climate Change (IPCC-AR4) states that “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” Carbon Dioxide (CO2) is responsible for the largest fraction of man-made climate forcing. More than 90% of the annual increase in radiative forcing since 2000 is due to CO2 alone. Evidence from carbon isotopes indicates that the increase in CO2 over the past century can overwhelmingly (>75%) be attributed to fossil fuel burning. The long-term trajectory of fossil fuel CO2 emissions however, is highly uncertain. Worst case scenarios made by the IPCC as recently as 2001 have already been proven to be too conservative in 2007. The impact of climate change on the natural exchange of greenhouse gases adds to this uncertainty.
Under the Kyoto protocol (2006-2012) the Netherlands, as part of the European Union, is committed to an 8% reduction of greenhouse gas emissions relative to 1990 levels; further European mitigation measures aim to reduce national emissions by as much as 20% (CO2 equivalent) by 2020. Recent G8 talks suggest even further reductions, up to 50%. Such drastic reductions are generally believed to be required to attain “manageable” levels of climate change. Reduction strategies will increasingly be expressed through the operation of carbon markets, with considerable financial implications.
The EU clearly needs

“An objective, unbiased, and independent verification of the compliance of countries to international treaties concerning greenhouse gas reductions”

Not all carbon exchange is influenced by human behavior. Natural uptake of carbon by vegetation and the oceans has reduced the full impact of man-made emissions by 60%, hence only 40% of the total emissions has ended up in the atmosphere. It is worth emphasizing that without this ‘discount’ the current atmospheric concentrations (390 parts per million (ppm)) would be almost double the pre-industrial concentration (i.e. about 500 ppm). Whether this discount will keep pace with growing emissions, or will increase or decrease under a new climate regime, is one of the largest unknowns in current climate predictions. Knowing how the uptake will develop in the future has immediate implications for reduction efforts. Reduced biospheric uptake implies that more severe emission reduction efforts will be required to attain stabilizing CO2 concentrations. Hence there is also a need for:

“A better understanding of the long-term behavior of the natural greenhouse gas sources and sinks”

The Scientific Context:

Making the observations
Observations form the basis of the ICOS-NL Integrated Data Interpretation Center. High quality measurements relevant for greenhouse gas research are being conducted all over the world. Examples are:

  • Local concentration measurements, which inform us about the distribution and change in greenhouse gas concentrations
  • Flux measurements, which give information about the local exchange of greenhouse gases with specific ecosystems
  • Aircraft measurements, which inform us about the spatial heterogeneity of concentration and flux fields
  • Satellite measurements, which provide a global view of the concentration distribution, also on the remote locations
  • Isotope measurements, which inform us about the magnitude of specific exchange processes

It is instructive to compare the challenge that we face for greenhouse gases with numerical weather prediction. In numerical weather prediction millions of observations from balloons, surface stations, and satellites are integrated in a numerical model to provide a weather forecast. Every 6 or 12 hours, sophisticated data assimilation algorithms estimate a new atmospheric state that is most consistent with observations and physics, and from that point on a new (and better) weather forecast for the next 10 days is started. The analysis of the state thus allows improved forecasts, while decade long sequences of the analyzed states are used to study recent climate.
In greenhouse gas research we also require a good analysis of the past and present state, and a reliable prediction for the future. However, we have a much more limited set of observations to work from, and the descriptions of the physics of the system are less complete. The time scales that we want to predict the state of the system for covers decades rather than days. Moreover, the greenhouse gas exchange processes at the surface strongly drive the future state of the greenhouse gas distribution. For methane and nitrous oxide the sink processes in the atmosphere also play a role.
One of the exchange processes that is relevant for policy concerns the man-made emissions from fossil fuels and other anthropogenic activities, such as rice production and waste management. The relevant question here is: are countries reducing their greenhouse gas emissions according to the treaties?
To predict the greenhouse gas concentrations on the longer timescales, we also want to know how the exchange processes evolve in time. Do the biosphere and oceans remain strong CO2 sinks also at the longer time scales? Are the natural wetlands producing more methane in a warmer climate? Are their signs of large emissions from melting permafrost?
Both the policy questions and the fundamental scientific questions call for a fundamental approach that is also used in weather prediction: data assimilation.

Exploiting the observations: data assimilation
The complexity of different data streams, interaction between variables, and uncertainty in observation and model output that is integral to the multiple constraint approach, make data assimilation one of the fundamental tools to make progress in greenhouse gas cycle research. In essence, data assimilation is an integration tool. The integration refers to the combination of different streams of information from trace gas measurements, satellites, accounting efforts, agricultural statistics, and mechanistic models of the greenhouse gas cycle components involved in the context of a model system. The total information will only be greater than the sum of the parts if effective ways to combine the strengths of each part of the system can be found. Data assimilation techniques have shown the potential to fulfill this role.
Data assimilation at such a scale requires substantial computer resources, and a team of scientists, scientific programmers, and software developers to be successful. Clearly, not every country in the EU can independently build and maintain the capacity for data assimilation. For weather forecasts for instance, this task has been delegated to the European Centre for Medium Range Weather Forecasts (ECMWF), which provides member states with expertise, computer code, supercomputing facilities, and daily weather products from their operational data assimilation system. A similar service for carbon cycle data assimilation will be provided to EU member states from the ICOS-NL Integrated Data Interpretation Center.
We plan to base the operational component of the center on one of the leading efforts in the carbon cycle community: CarbonTracker. CarbonTracker estimates global CO2 exchange on a 1x1 degree latitude/longitude grid (equivalent to ~ 60x100 km over the Netherlands) each week. In ICOS, an even finer mesh is needed to accurately estimate CO2 and other greenhouse gas. This requires the ‘nesting’ of a mesoscale atmospheric model such as the Weather Research Forecast (WRF) model into the global CarbonTracker simulation. Mesoscale models are now capable of representing most of Western Europe on a 4x4 km grid, allowing much more detail in how the surface area is represented, and in resolving GHG transport patterns. Combining CarbonTracker with a mesoscale model can provide “seamless analysis” of GHG sources at high spatial resolution given a sufficient density of observations.
Operational products will include daily maps of regional GHG exchange, estimates of fossil fuel emissions for the major industrial areas of Europe, reanalysis of major European carbon cycle events such as droughts, and also specialised products for policy makers (GHG trends, country totals, …). All results will be disseminated following the ICOS-EU open access policy, and will use a dedicated ICOS-NL web portal linked to the ICOS central carbon portal.
In addition to operational products, the ICOS-NL center will enable research across ICOS member countries by providing components from the operational system to research efforts. A strictly modular design of the data assimilation system will allow interested parties to take for instance the operational model infrastructure, but substitute their own meso-scale transport model that might have specific physics to deal with elevated terrain. Or similarly, some groups might want to use the infrastructure to develop and test new methods to assimilate oxygen measurements into the system. The ICOS-NL center will provide such efforts with the computer code, system documentation, training, and supercomputing resources to complete their research. Our European partners can thus use the ICOS-NL infrastructure to perform scientific experiments, similar to service offered by for instance CERN.
Summarizing, the ICOS-NL Integrated Data Interpretation Center will perform and facilitate

  • assessments of the present day GHG balance,
  • retrospective studies of major events such as droughts,
  • improvement of mechanistic descriptions in the model,
  • attribution of anomalies to terrestrial GHG cycle processes and detection of long-term trends or feedbacks in the greenhouse gas balance.

The Policy Context:

ICOS-Europe:
Carbon dioxide, methane and nitrous oxide concentrations and the flux of carbon dioxide have been identified as Essential Climate Variables in the Global Carbon Observation System (GCOS). Observations of the Essential Climate Variables (ECV) are required to support the work of the United Nations Framework Convention on Climate Change (UNFCCC) and the Intergovernmental Panel on Climate Change (IPCC).

ICOS-NL:

Ideas for brochure:

  • Insert text balloons + fancy graphics to explain difficult concepts
  • Make a glossary of terms/index
  • Identify in footnotes the current/past research efforts in the Dutch community where appropriate
  • Make a list of science questions addressed
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