This contract will develop improved algorithms to produce long term ocean reanalyses in the presence of varying observational networks. It will be focused on consistency of climate relevant metrics across 2 periods of increasing observational coverage, in the 1950’s and in the 1980s-90s as altimeter observations become available. The role of different atmospheric forcing and riverine inputs will be tested and the ensemble error covariance approaches suitable for both sparse will be developed and more dense observing networks. It will also address the detection of bias in the assimilated results and make recommendations on how best to treat bias under varying observational conditions. Finally new post-processed smoothing methods to more fully use observations and to spread information back to influence more sparsely observed periods will be applied. A set of Recommendations will be made to CMEMS to aid in the production of a climate- consistent long period ocean reanalysis in the final report.
25 months from 09/09/2024 to 30/09/2026
General aims
In the last half a century the observation network has been completely revolutionised. ORACS projects intends to propose advices and solutions for the production of a long-term reanalysis across several observation network changes. The sudden ingestion of new datasets, during the assimilation step, can potentially spoil the consistency of the timeseries for the essential ocean variables and climate indexes
CMCC role
PI of the project
Activities
Studies concerning ocean biases and smoothing procedures. Testing possible a-priori and a-posteriori solutions: inclusion of ensemble error covariances in variational scheme and application of smoothing procedure in post-processing.
Expected results
Focusing on two different periods (50s and 90s) ORACS project is meant to describe possible solutions to avoid non-physical discontinuities in climate indexes that could be generated by the sudden ingestion of new types of data.
Partners
UREAD – University of Reading; CNR-ISMAR-Consiglio Nazionale delle Ricerche-Istituto di Scienze Marine