Establishment of a local operational oceanography system: application in the Cantabrian coast

authors: Maitane Olabarrieta, Sonia Castanedo, Raul Medina, Inigo J. Losada, Angel David Gutierrez

Affiliation: Ocean and Coastal Research Group, IH Cantabria, Universidad de Cantabria. Avda. de los Castros s/n. 39005, Santander, Spain.


Abstract: As a consequence of the Prestige oil spill (November, 13th, 2002) the Spanish Ministry of Science funded the ESEOO (Establishment of an Operational Oceanography System in Spain) project. The work described in this paper is part of ESEOO´s 4.3 task, known as “Local scale circulation model”. The main objective of this task is to develop and improve the tools required to predict currents and trajectories of pollutant in local areas, including harbours and estuaries. This paper focuses basically on the development of the algorithms and procedures required to perform the downscaling from regional to local models, and on the establishment of an operational system in the North coast of Spain and in the West Coast of the Cantabrian coast.

The developed downscaling process links the regional hydrodynamic model with the local model. The regional model used in ESEOO is the POLCOMS (Proudman Oceanographic Laboratory Coastal Ocean Modelling System) model (Holt and James, 2001) and it runs operationally in Puertos del Estado forecast system. The regional model has a spatial resolution of 0.05º and covers the whole Atlantic domain around Spain (ESEOAT grid).

The local hydrodynamic computations are carried out using the ROMS model (Shchepetkin and McWilliams, 2005). This model was modified by Peven et al. (2006) to take advantage of the AGRIF (Adaptative Grid Refinement in Fortran) package (Debreu and Vouland, 2003). In order to make a downscaling from the regional to the 300 m resolution local domain, a two step downscaling is performed. Taking as initial and boundary conditions those given by the ESEOAT model, an intermediate resolution model is also run to provide the required boundary conditions to the local model. The high resolution model operates embedded to this intermediate grid. The nesting between the intermediate grid and the high resolution grid is a one way nesting, Peven et al. (2006).

The developed operative system provides a two day forecast of the ocean surface currents, temperature and salinity. A preliminary analysis shows a good agreement between computed and measured sea surface elevations.