The oceans have the largest heat capacity in the climate system, therefore controlling the rate of climate change. Syntheses of the ocean state using models constrained by observations are critical for understanding climate and predicting climate variability. However, there has been little organised activity evaluating them. Clear information is needed about the strengths and weaknesses of ocean syntheses, as well as guidelines on how fit for different purposes various ocean syntheses are. The main goals of this Action are to improve the coordination of the European efforts in the evaluation of ocean syntheses, to optimize their use and value, to ease their access, to promote their improvement and to raise confidence in their quality.
Working Group 1: Preparation and harmonization of data will establish a set of ocean syntheses and independent datasets that will be used for comparison. Examples of independent datasets needed are air-sea heat fluxes, ocean circulation estimation, satellite-derived datasets and delayed-time in situ measurement data bases. A catalogue will be built and updated through the Action including these products. This catalogue will be hosted in the Action official webpage. A review of the data and metadata available to be incorporated in the ocean syntheses will be also performed. A list of the possible applications for ocean syntheses will be also compiled, reflecting what are the end-users needs.
Working Group 2: Evaluation of ocean syntheses will address the ocean synthesis evaluation exercises. An assessment of the quality of the participating ocean syntheses and their intercomparison will be realised. Derived variables, such as air-sea fluxes and transports, will be also evaluated. The final goal is to make a series of recommendations on the best use of these syntheses for the arious applications compiled in WG1. New variables can allow a better characterization of the surface heat and freshwater fluxes if integrated to the ocean syntheses. These new datasets will have stable accuracy and their incorporation to the ocean syntheses will allow for an improved estimate of the state of the ocean.
Working Group 3: Applications from short-term predictability to climate studies. In addition to quantifying the error of the ocean synthesis products participating in the Action, it is important to study their strengths and weaknesses when these are used in the specific applications they have been designed for. The activities performed within this WG will be of utmost importance to determine how fit are ocean syntheses for different uses, and recommendations to the end users will be done based on the conclusions reached through these tasks. The advancement of research and knowledge about the quality of the ocean syntheses can result in an extended final list of studied applications.
Working Group 4: Downscaling issues from global to regional sytheses. Within this WG the following activities will be addressed: (i) Study of the impact of using higher resolution on the quality of the (regional) ocean synthesis products and their applications; (ii) Assessment of the optimal temporal frequency of boundary conditions for specific applications; (iii) Study of the impact of bathymetry and bottom friction on tidal dynamics in regional syntheses; (iv) Assessment on the impact of tidal dynamics resolution in nested ocean models: impact of forcing fields (boundary conditions) and quality of tidal dynamics in high resolution models; (v) Inter comparison of regional and global syntheses: assessment of quality and skill against.