Description of work

The goal of this cross-cutting work package is to develop and test scientific methodologies to merge predictions from the regional and global (initialised and non-initialised) model simulations into a seamless prediction system, and to provide useful information for the stakeholders at the regional scale. Such a seamless prediction system will ultimately not only provide actionable climate information but also be used for climate-related risk assessments, climate change adaptation programmes and businesses operating at a regional and local scale.

Deriving seamless climate information across the 1-40 year prediction time scale involves assessing the performance of each system depending on the prediction lead time, identifying situations where one of the systems can be shown to have added value over the other and over any benchmark that can be identified. A key element will be applying approaches to understand when the information provided by the initial conditions is no longer adding value and under which conditions the information provided by the non- initialised forced predictions will be useful at the regional scale. The merging of regional and global climate information will be explored further in this work package for three methodologies: blending of PDFs, creation of discrete scenarios, and storylines of individual events. The different predictions will be combined such that users of the seamless system are presented with trustworthy, self-consistent climate information about the future.

Objectives

The aim of this cross-cutting work package is to develop methodologies to bring together initialised decadal climate predictions (WP1), non-initialised climate projections (WP2) based on global climate models, and high-resolution regional climate projections (WP3) in order to provide seamless climate information for users over a period of 1 to 40 years into the future with a focus on the European region. Its objectives are:

  • Comparison of predictions based on global initialised versus non-initialised simulations for common prediction time horizons. Estimation of the prediction time until which the initialised predictions show skill compared to non-initialised simulations for different large-scale and local variables.
  • Combine global initialised forecasts with non-initialised forced-only predictions. Tests of the combining methods with a perfect model setting. Estimation of added value for combined predictions for different variables and regions.
  • Develop methods to merge information from the high-resolution regional model simulations with global climate predictions.
  • Evaluate the extent to which observational, physical and emerging constraints are reflected in the predictions of variables of direct relevance for (local) users.
  • Develop storylines and cases consistent with the result of the combined forecasts and according to the user needs identified.

The final goal is the integration across the European climate forecast systems developed for CMIP6 and those that will be built on them, making them a credible, reliable, authoritative, and action-oriented source of climate information to support more climate-resilient European economies and societies.