Project aims

It is essential to estimate the quality of the decadal projections within MiKlip for all involved model components. The VALOCEAN work package will evaluate the oceanic part of the model hindcasts and will aim at a process-oriented validation to enhance the understanding of the processes represented in the model. For the model validation/evaluation a variety of oceanic observational data sets will be assembled and time series of key parameters will be constructed. These key parameter sets will be compared with the hindcast simulations and with the oceanic reanalysis data sets, which are used for the model initialization.

Project structure

It is important for the quality of the MiKlip decadal predictions that the model not only reconstructs the mean state of the ocean but also realistically reconstructs the temporal evolution. Consequently, the comparison of model outputs with observed time series is an important measure in the assessment of the MiKlip decadal prediction system. One of the main tasks therefore is to collect available oceanic observations and integrate them into the central evaluation system (CES). Based on these observations key oceanic indices will be constructed. These indices shall represent various aspects of the ocean dynamics through time and space integrating properties. Such properties are e.g. ocean heat content (OHC), ocean freshwater content (OFC), mixed layer depth (MLD), the Atlantic multi-decadal oscillation index (AMOI) and other indices which represent the strength of the subpolar and subtropical gyre. It is planned to use homogenized and quality assessed data sets from the Argo and satellite observation programmes (SST, SSH) but also historical data like the world ocean data base, as well as time series from moorings (i.e. TAO/TRITON).

Realistic reanalyzes are prerequisite for the initialization of the MiKlip decadal prediction system. Thus, oceanic reanalyzes and hindcasts have to be evaluated for their temporal evolutions. The spatial focus will be on key regions such as the subpolar Atlantic and the tropical oceans. The investigations will identify differences and their possible implications for ocean dynamics.

The work in VALOCEAN is divided into four tasks and is listed below.

Tasks of the project and deliverables

  • Construct OHC and OFC data products based on multi-instrument sources (Argo data, historical measurements with appropriate uncertainty estimates (Milestone M3.1)
  • Comparison and evaluation of the reanalysis data sets with observations (Milestone M3.2)
  • Construction of time series of oceanic key indices and their implementation in the central evaluation system (Milestone M3.3)
  • Examination of spatial patterns and the temporal evolution of multi-decadal variability in observations and model output (Milestone M3.4)

Progress so far

Work has started with the collection of observational data sets and the comparison of the reanalysis data sets.