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Major themes | Theme 1 | CCMAP

CCMAP (Climate-carbon modelling, assimilation and prediction)

Leader: Dr. Eleanor Blyth (CEH, Wallingford)

Overview and Goals

CCMAP's Principal Investigator was Dr. Eleanor Blyth, with subcontracts to the Universities of Bristol (Dr. Wolfgang Knorr, Earth Sciences and QUEST; Andy Ridgwell, School of Geography) and Oxford (Physical Oceanography, Prof. David Marshall).

The general scientific background of CCMAP is provided by the wider goals of QUEST, namely:

In this context, the specific goals of CCMAP were:

  1. to quantify the climate-carbon cycle feedback and the underlying processes
  2. to provide a range of standardised validation data set for for the carbon cycle component of Earth System Models.

CCMAP built on developments to CCDAS (Carbon Cycle Data Assimilation System) in the early stages of QUEST, to include satellite data of vegetation and fire.

Rationale

Recently published results from the Coupled Climate-Carbon Cycle Model Intercomparison Project (C4MIP) have shown that there is an enormous amount of uncertainty surrounding the magnitude of the climate-carbon cycle feedback [Friedlingstein et al. 2006]. Most likely, one of the principal reasons for this uncertainty is a lack of observational constraint for the climate and carbon cycle models used in C4MIP. CCMAP was designed to change this situation and to provide simulations that are systematically constrained by observations, mainly of the carbon cycle, but also – in the form of a feasibility study – the climate system.

There were several activities, within QUEST, Exeter University and at CEH which aimed to form a cohesive methodology to reduce uncertainty in both climate and carbon-cycle modelling based on observations. On the one hand, JULES was further developed to improve the carbon-cycle element under QUEST, CEH developed a bench-marking system for the JULES land surface model and Exeter University worked on an adjoint of JULES which could be used in inverse modelling.

The project used state-of-the-art inverse modelling techniques to utilize the major available observational data relevant for the global scale of the problem. These techniques need to be used to identify (a) the spatial location, temporal variation and causes of carbon dioxide sources and sinks, and (b) the likelihood, magnitude and timing of a transition in the terrestrial biosphere from being a global carbon sink to a source.

The simplest form of this is the carbon-cycle only model. This has already been done by Freidlingstein et al (called CCDAS), but an updated version, with improved soil respiration and carbon dioxide fertilization (taken from JULES) and a new ocean model would be a significant improvement. A more complete analysis would include the full climate-carbon-cycle. This has not been attempted before. This is an ambitious and future-reaching element to CCMAP, and would take the form of a feasibility study.

In addition to research needs identified by the scientific community, CCMAP will also respond to the need for policy relevant information, as it is relevant for the mission of QUEST. There is a renewed UK policy emphasis on assessing emissions pathways to stabilize CO2, which CCMAP addressed directly. The magnitude of the climate-carbon cycle feedback is crucial for the future relationship between emissions and concentrations of CO2.

Objectives

CCMAP’s strategy to achieve its above goals is divided into three work packages with the following objectives:

Participating Groups