A 44-year (1958–2001) sea level residual hindcast over the Mediterranean Basin

Abstract

The present work describes a 44-year integration of a two dimensional sea level model forced by atmospheric pressure and wind over the Mediterranean Sea. As an output of such long-term hindcast a sea surface residual database containing storm surge events was created. Storm surge is a critical parameter in different kinds of studies, from harbor design to coastal dynamics. This work focuses on studying the regional evolution of the atmospheric forcing contribution to the residual sea surface variation. Modeling sea level residual in the Mediterranean Sea is of particular interest because the response of the sea to the atmospheric forcing may be important in comparison to the tidal amplitudes. The integration was performed by means of the HAMSOM numerical model in a barotropic mode. Hourly HIPOCAS hindcast wind and atmospheric sea level pressure fields were used to force the sea level model. These forcing fields were generated by dynamical downscaling from the NCEP/NCAR global reanalysis through the atmospheric REMO model. Measured residual sea surface is well reproduced by the model with a coefficient of correlation of the order of 0.82 at various Spanish harbor locations. On the other side, the study of the climatological sea surface elevation shows that the Mediterranean Basin has undergone negative trends over the past 44 years: a mean negative rate of −0.8 mm/yr is found in the central basin and extreme values as large as −2.0 mm/year in the Adriatic Basin.