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The 9 longest tide‐gauge records in the Mediterranean Sea are compared with the output of a barotropic model forced by atmospheric pressure and wind. Between 1958 and 2001 the tide‐gauges indicate sea level trends of −0.4 to 0.7 mm/yr. During the same period the model shows sea level reduction of −0.4 to −0.7 mm/yr linked with the North Atlantic Oscillation (NAO). After the removal of the meteorological influence from the sea level records the resulting trends are ∼0.3 ± 0.4 mm/yr at the western Mediterranean and ∼1.3 ± 0.4 mm/yr at the eastern Mediterranean. The eastern basin is strongly affected by rapid sea level rise in the period 1993–2001 with rates of 5–10 mm/yr which are probably related to the Eastern Mediterranean Transient (EMT).

[1] Sea-level time series recorded at three stations of the northern Spanish coast (Santander, Coruña, and Vigo) are examined with the aim of obtaining reliable interdecadal trends. The records are about 6 decades long, and their consistency is checked by means of an Empirical Orthogonal Function (EOF) analysis. Major benefits of the analysis are the detection of undocumented changes of sea-level reference and the filling of data gaps. For the last decade, the consistency of the trends is also checked against shorter, collocated and nearby records. Results indicate that during the second half of the twentieth century, sea level has been rising at a rate of 2.12, 2.51, and 2.91 mm/yr in Santander, Coruña, and Vigo, respectively. Meteorologically induced trends are evaluated from the output of a sea-level numerical model forced by a re-analysis of 44 years of atmospheric data. Results are À0.44, À0.27, and À0.21 mm/yr, respectively, indicating that in the study region the meteorological forcing acts in the sense of slightly slowing the sea-level rise. On the other hand, sea-level records and the North Atlantic mean temperature exhibit a similar interannual evolution, which points to the thermosteric effect as responsible for the positive trends. Regarding the difference between stations, about a third of it can be attributed to spatial differences in the meteorological forcing. The remaining contribution is attributed to spatial differences in the increase of the ocean heat contents, as suggested by the analysis of SST series during the last decade.

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Abstract. This paper addresses the problems of overlapping sea level time series measured using different technologies and sometimes from different locations inside a harbour. The renovation of the Spanish REDMAR (RED de MAReó-grafos) sea level network is taken here as an example of the difficulties encountered: up to seventeen old tide gauge stations have been replaced by radar tide gauges all around the Spanish coast, in order to fulfil the new international requirements on tsunami detection. Overlapping periods between old and new stations have allowed the comparison of records in different frequency ranges and the determination of the impact of this change of instrumentation on the long-term sea level products such as tides, surges and mean sea levels. The differences encountered are generally within the values expected, taking into account the characteristics of the different sensors, the different sampling strategies and sometimes the different locations inside the harbours. However, our analysis has also revealed in some cases the presence of significant scale errors that, overlapping with datum differences and uncertainties, as well as with hardware problems in many new radar gauges, may hinder the generation of coherent and continuous sea level time series. Comparisons with nearby stations have been combined with comparisons with altimetry time series close to each station in order to better determine the sources of error and to guarantee the precise relationships between the sea level time series from the old and the new tide gauges.

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Abstract. ENSURF (Ensemble SURge Forecast) is a multimodel application for sea level forecast that makes use of several storm surge or circulation models and near-real time tide gauge data in the region, with the following main goals:1. providing easy access to existing forecasts, as well as to its performance and model validation, by means of an adequate visualization tool;2. generation of better forecasts of sea level, including confidence intervals, by means of the Bayesian Model Average technique (BMA).The Bayesian Model Average technique generates an overall forecast probability density function (PDF) by making a weighted average of the individual forecasts PDF's; the weights represent the Bayesian likelihood that a model will give the correct forecast and are continuously updated based on the performance of the models during a recent training period. This implies the technique needs the availability of sea level data from tide gauges in near-real time. The system was implemented for the European Atlantic facade (IBIROOS region) and Western Mediterranean coast based on the MA-TROOS visualization tool developed by Deltares. Results of validation of the different models and BMA implementation for the main harbours are presented for these regions where this kind of activity is performed for the first time. The system is currently operational at Puertos del Estado and has proved to be useful in the detection of calibration problems in some of the circulation models, in the identification of the systematic differences between baroclinic and barotropic models for sea level forecasts and to demonstrate the feasibility of providing an overall probabilistic forecast, based on the BMA method.