Nivmar: A storm surge forecasting system for Spanish Waters

In this paper, a storm surge prediction system for the Spanish Waters is pr esented. The system, named Nivmar, is based on the ocean circulation Hamsom model and on the harmonical prediction of tides computed front data measur ed by the tide gauge network Redmar, managed by Puertos del Estado. Nivmar is executed twice a day, running Hamsom forced by meteorological fields der ived from the INM (Instituto Nacional de Meteorologia) operational applicat ion of Hirlam atmospheric model. Data from Redmar tide gauges is used to to forecast the tidal elevations, to validate the system and to perform data assimilation, correcting systematic errors in the mean sea level due to phy sicals processes that are not included in the ocean model (i.e. steric heig ht). The forecast horizon is 48 hours. In order to validate the system with measured data from Redmar a very stormy 5 months period was selected. Resu lts from this test (November 95 to March 96) are presented. Data from this experiment shown that Nivmar is able to correctly predict sea level in the region. A simple data assimilation scheme for sea level is described and re sults front its application are studied. Finally, special focus is made in future plans and potential developments and applications of the system.