Supplementary material to “Improving Our Understanding of Earth System Processes Within the GREENCYCLES EUROPEAN Training Network”

Nicholas Stephens, Max-Planck-Institut für Biogeochemie, Jena, Germany; Sönke Zaehle, CNRS Laboratoire des Sciences du Climat et de l’Environnement, Gif-sur-Yvette, France; Ben Poulter, Department of Global Change and Natural Systems, Potsdam Institute for Climate Impact Research, Potsdam, Germany

Citation:
Stephens, N., S. Zaehle, and B. Poulter (2007), Improving our understanding of Earth system processes within the GREENCYCLES European training network, Eos Trans. AGU, 88(38), 372. [ Full Article (pdf)]

GREENCYCLES brings together scientists from both observational and modelling backgrounds, provides new observations where necessary, and uses these and other data to evaluate process formulations in local- to global-scale models. Research in GREENCYCLES is organised around 6 key science objectives:

  1. Quantify feedbacks in the global carbon cycle;
  2. Determine the effects of changing land use on climate;
  3. Improve understanding of natural sources of methane and their responses to human activities;
  4. Quantify impacts of climate change and climate variability on fire-induced emissions of greenhouse gases;
  5. Quantify impacts of climate change on terrestrial and oceanic biogenic emissions of aerosols and chemically active gases, and their effects on tropospheric chemistry; and
  6. Quantify impacts of vegetation and climate changes on atmospheric dust, and its feedbacks on carbon dioxide and climate.

Each of the Early Stage Researcher and Experienced Researcher projects have 'been defined within one of these five objectives (Table 1 [pdf]).

GREENCYCLES training of young scientists relies on three concepts:

  1. training by research in collaboration with one or more senior scientists at other research institutes within the network during an extended research secondment,
  2. targeted workshops on themes of special interest, also involving key scientists outside of GREENCYCLES, and
  3. general training and personal skill development.

Additional guidance on scientific and career development is made available through a mentoring system between an Experienced and each Early-Stage Researcher.

Global Carbon Feedbacks – Oceans

Maciej Telszewski (UEA, see Table for abbreviations) has been using his secondment at CEA to utilise a neural network technique to spatially and temporarily map sea surface pCO2 (partial pressure of carbon dioxide) in the North Atlantic. His technique includes the use of in situ measurements, satellite derived information, model and reanalysis data. An additional observational constraint on the ocean-atmosphere net carbon flux is being developed by Valentina Sicardi (MPI-BGC), who is improving current inversion methods of atmospheric carbon concentrations by using ‘apparent potential oxygen’ measurements. Together, these data-sets will provide valuable information to better quantify the present ocean-atmosphere net carbon flux and to evaluate ocean carbon models. Nicholas Stephens (MPI-BGC) has been working with such an ocean model with a more detailed representation of plankton functional diversity and ocean nutrient cycles. These advances will significantly improve model representation, the ability to simulate biogeochemical feedbacks and ocean-atmosphere carbon fluxes.

Global Carbon Feedbacks – Land

Collaboration between Raquel García Gonzalez (CEA) and Trevor Keenan (CREAF), with reciprocal secondments, is leading to an improved understanding of the effects of seasonal water stress on carbon fluxes in Mediterranean ecosystems. This understanding has greatly improved the performance of ecosystem models in drought-prone ecosystems that are typically poorly described in Earth System Models. This work complements research by Ben Poulter (PIK), who is using ecosystem observations to evaluate a dynamic global vegetation model, and subsequently identify important drivers, such as climate, fire and land-use change, and potential feedbacks that may lead to Amazonian forest dieback. These studies are closely linked with the development of a coupled carbon-nitrogen cycle parameterisation for a terrestrial biosphere model by Sönke Zaehle (CEA). This work integrates novel parameterisations of ecosystem processes based on recent physiological understanding. Together, the subgroup is providing improved estimates of long term terrestrial ecosystem responses to environmental change.

Fire emissions – sources and consequences

A workshop was held on the quantification and modelling of fire induced carbon emissions (and other radiatively important gases) in Bristol (26-28th May 2006), where the GREENCYCLES fire group identified the combination of remotely sensed information with process based modelling approaches as one of the most important current research tasks. Yannick Le Page (ISA) is analysing remotely-sensed, spatially explicit time-series of fire observations for his secondment at MetO to evaluate and improve current process-based fire modelling. Marlies Gumpenberger (PIK) evaluates the effects of various land-use policies on global biogeochemistry, using data analyses and process-based modelling. Her work provides amongst others an assessment of land-use and agricultural residue burning as an additional source of fire-related emissions. These studies link closely to the work of Tomek Kasikowski (MetO) who will develop improved representations of land-use and fire in the MetOffice’s global climate model, to analyse the potential effect of fire emissions and land-use on climate.

Methane emissions – sources and consequences

Extensive collaboration between Marcin Jackowicz-Korczynski (ULUND) and Roxana Petrescu (VUA) includes measuring methane emissions in boreal mires and subsequent interpretation of these measurements using a site-specific process model. These studies will increase our understanding of the drivers behind wetlands biogeochemistry, carbon dioxide and methane fluxes. In February 2007, a workshop was held in Lund to evaluate methane flux observations and modelling at various scales. One of the main outcomes was an assessment in the use of in situ observations to improve global modelling efforts at the GREENCYCLES partners UBRIS and CEA.

Aerosols and chemically active gases

In addition to GREENCYCLES research on the quantification of fire-related aerosol emissions, the work by Meike Vogt (UEA) is leading to a clearer understanding of the significance of dimethylsulphide in the global aerosol budget. Her analysis of biogenic sources of dimethylsulphide in the ocean and controlling factors is conducted from both an observational and modelling perspective. Trevor Keenan (CREAF) has tested various modelling approaches to describe terrestrial Biological Volatile Organic Compounds (BVOCs) emissions from European forests. This will be of use for a new Early-Stage Researcher at the MetO to research the effect of BVOCs and methane on the climate system.

Long-term constraints and modelling of feedback mechanisms

The measurement of carbon dioxide and its stable 13C isotope trapped in the EPICA/DOME C Antarctic ice core by Anna Lourantou (CNRS-LGGE) provides new data on past variations in atmospheric carbon dioxide concentrations. A preliminary data interpretation using an ocean box model during her secondment at CEA and UBRIS has provided novel insights into oceanic processes that potentially played a major role during the last deglaciation. Changes in global atmospheric dust loading between the last glacial maximum (21 kBP) and present-day are recorded in marine and terrestrial sediments in addition to ice cores. These provide crucial data for Sarah Shannon (UBRIS) to evaluate her newly developed global dust cycle model, coupling a dynamic global vegetation model with a model of dust emissions.

Acknowledgements

The information presented here is a product of all GREENCYCLES scientists. GREENCYCLES would like to thank the Institut d'Estudis Catalans and the Societat Catalana de Biologia for hosting the meeting. Support of the network by the EC FP6 Marie Curie Action is gratefully acknowledged (MRTN-CT-2004-512464).