Assessment and validation of the new multivariate Mercator high resolution forecasting system.
Jean-Michel Lellouche(1) , Mounir Benkiran(1) , Laurence Crosnier(1) , and Eric Greiner(1)
8-10 rue Hermes, Parc Technologique du Canal,
31520 Ramonville Saint Agne,
The Mercator Ocean Monitoring and Forecasting System is routinely operated in real-time in Toulouse by the Mercator Project since early 2001, and has been regularly upgraded through three prototypes of increasing complexity (PSY1, PSY2 and soon PSY3), expanding the geographical coverage from regional to global, improving models and assimilation schemes.
In this contribution, we focus on the North Atlantic and Mediterranean High Resolution Prototype PSY2. The ocean model is based on OPA-8.1, a general circulation model developed at LODYC (IPSL Paris), and is designed to simulate the Atlantic and Mediterranean oceans with a very high horizontal resolution (5 to 7 km). The assimilation system is based on the Reduced-Order Optimal Interpolation algorithm and uses 1D vertical multivariate EOFs to extract statistically-coherent information from the observations. The multivariate PSY2 system assimilates conjointly altimeter data, SST and in situ observations (temperature and salinity profiles).
After a brief presentation of the high resolution forecasting system, we will present some recent results obtained with the multivariate PSY2 prototype compared to the previous monovariate one. In particular, the assimilation of temperature and salinity vertical profiles allows to better represent water masses like mode waters and the Mediterranean Water Outflow. In the POMME area (16-22°W and 38-45°N), the mixed layer depth and its seasonal cycle are well represented. In the Gulf of Mexico, the new system is successful at representing realistic loop current eddy shedding.