Use of Models and Facility-Level Data in Greenhouse Gas Inventories

Use of Models and Facility-Level Data in Greenhouse Gas Inventories
3 Use of Models in Good Practice National Greenhouse Gas Inventories
In the application of models in National Greenhouse Gas Inventories, critical issues are suitability, parameterization,
calibration, evaluation, and uncertainty 3 . It is crucial that they are all reported and documented transparently in order for
the model results to be understandable, assessable and credible. These issues are discussed in the 2006 IPCC
Guidelines and good practice inventories will follow the approach given there. The participants noted that the most
detailed discussion of the use of models is given in the AFOLU volume (Volume 4), but that the approach given there is
relevant to all sectors.
There are no specific requirements for all the items needed to be reported to ensure transparency provided in the IPCC
good practice guidance. Lack of transparency and inconsistent documentation was identified as a major concern by
participants at this meeting. It was highlighted that a specific effort to make model results assessable by users of
reported information is crucial. The participants believe that experience in the use of models in national greenhouse gas
inventories has increased and this provides a basis for transparent reporting and documenting of the use of models. The
participants considered that the inclusion of key elements of the model in a brief model description
4
would be one
component to improve transparency. These elements are:
• Basis and type of model (statistical, deterministic, process-based, empirical, top-down, bottom-up etc.);
• Application and adaptation of the model (description of why and how the model was adapted for conditions
outside the originally intended domain of application: See Section 3.1 “Suitability”) ;
• Main equations/processes;
• Key assumptions (important assumptions made in developing and applying the model);
• Domain of application (Description of the range of conditions for which the model has been developed to
apply) 5 ;
• How the model parameters were estimated;
• Description of key inputs and outputs;
• Details of calibration and evaluation with calibration data and independent data (showing intermediate outputs
at an adequately disaggregated level);
• Description of the approach taken to the uncertainty analysis and to the sensitivity analysis, and the results of
these analyses;
• QA/QC procedures adopted;
• References to peer-reviewed literature (where details of the research on the model can be found).
The remainder of this chapter considers specific issues in the development, calibration and evaluation of models and, in
the light of experience, indicates what should be reported in order for the model results to be transparent.
3.1 Suitability
Suitability is the applicability of model and its adaptation to the specific national situation in which the model is used for
greenhouse gas inventory purposes. Where an existing model is selected inventory compilers need to consider and
document the following questions:
• Is the model designed for, or portable to, the current national circumstances?
3 For suitability, parameterization, calibration and evaluation, see Volume 1, Chapter 2 “Approaches to Data Collection” and Volume
4, Chapter 2 “Generic Methodologies Applicable to Multiple Land-Use Categories”. For uncertainty, see Volume 1, Chapter 3
“Uncertainties”.
4 This could be described in approximately one page, and could be a hypertext document with appropriate references to data tables
and literature, if possible.
5 Model outputs should match the definitions and requirements of the IPCC Guidelines.
IPCC Expert Meeting Report 14 TFI