QUEST Theme 1 - CCMAP (Climate-carbon modelling, assimilation and prediction) Project

Introduction

Overview and Goals

The general scientific background of CCMAP is provided by the wider goals of QUEST, namely: improved understanding and knowledge leading to influential international publications on the pattern, mechanisms and prognosis for land and ocean uptake of anthropogenic CO2 and information for policy makers concerning the environmental consequences of different scenarios of greenhouse gas emissions.

In this context, the specific goals of CCMAP are:

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

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

The goals stated above require the use of state-of-the-art inverse modelling techniques that are able 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 will address directly. The magnitude of the climate-carbon cycle feedback is crucial for the future relationship between emissions and concentrations of CO2.

CCMAP will not operate in isolation, but will build on important synergies with on-going research elsewhere in the UK, as well as on an existing world-leading data assimilation system of the carbon cycle. It will from the start build strong links with the Joint UK Land Simulator (JULES) Project Office (developing the UK's land processes and land carbon cycle model) hosted at the Centre for Ecology and Hydrology, the University of Exeter, and the MetOffice (jointly developing the adjoint of JULES and its implementation in a carbon cycle data assimilation system; Prof. Peter Cox and Dr. Chris Jones). In addition, CCMAP will build links with C4MIP, contributing and sharing data sets and working toward improved predictions of the future climate-carbon cycle feedback, and cooperate directly with other QUEST projects, in particular QUERCC and MARQUEST.

Objectives

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

WP1: Synthesis of a range of data sets for testing global carbon cycle and coupled climate-carbon cycle models and development of an appropriate tool-box for easy model testing.
WP2: Development of a world-leading inverse modelling tool for using coupled carbon cycle component models together with global-scale observations within a Bayesian parameter estimation and data assimilation framework, and application of this framework for quantifying the strength of the carbon cycle feedback complete with uncertainties.
WP3: A demonstration study to evaluate the potential for a similar parameter estimation framework, but using a coupled climate model. This is the first, necessary, step towards quantifying the climate-carbon-feedback (goal #1), as it includes the energy and water constraints on the system.

Availability of data and file format

Data will be stored in the BADC QUEST CCMAP project data archive.

The data filenames should follow the BADC File Name convention and the data file format should be NetCDF or NASA-Ames.

Access to data and information

Please refer to the QUEST Conditions of Access page for details of access restrictions.

Citation

et. al

Date of citation

Who to contact

The Principal Investigator will be Dr. Eleanor Blyth at the Centre for Ecology and Hydrology at Wallingford, 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).

Each QUEST project will have a designated "data co-ordinator" to ensure good communication with the QUEST core team/BADC regarding data issues, and to ensure that each project meets its data provision obligations. The data co-ordinator for the CCMAP project is to be determined.

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