Reconstructions of Mediterranean ocean temperature fields back to 1950 show a proxy relationship between heat content changes in the North Atlantic and the Western Mediterranean Deep Water (WMDW) formed in the Gulf of Lions in winter, because of consistent air‐sea heat fluxes over these areas, strongly correlated to the North Atlantic Oscillation (NAO).

Abstract. The Mediterranean Forecasting system Pilot Project has concluded its activities in 2001, achieving the following goals: Realization of the first high-frequency (twice a month)Voluntary Observing Ship (VOS) system for the Mediterranean Sea with XBT profiles for the upper thermocline (0-700 m) and 12 n.m. along track nominal resolution;2. Realization of the first Mediterranean Multidisciplinary Moored Array (M3A) system for the Near-Real-Time (NRT) acquisition of physical and biochemical observations. The actual observations consists of: air-sea interaction parameters, upper thermocline (0-500 m) temperature, salinity, oxygen and currents, euphotic zone (0-100 m) chlorophyll, nutrients, Photosinthetically Available Radiation (PAR) and turbidity;3. Analysis and NRT dissemination of high quality along track Sea Level Anomaly (SLA), Sea Surface Temperature (SST) data from satellite sensors to be assimilated into the forecasting model;4. Assembly and implementation of a multivariate Reduced Order Optimal Interpolation scheme (ROOI) for assimilation in NRT of all available data, in particular, SLA and VOS-XBT profiles;5. Demonstration of the practical feasibility of NRT ten day forecasts at the Mediterranean basin scale with resolution of 0.125 • in latitude and longitude. The analysis or nowcast is done once a week;6. Development and implementation of nested regional (5 km) and shelf (2-3 km) models to simulate the seasonal variability. Four regional and nine shelf modelsCorrespondence to: N. Pinardi (n.pinardi@ambra.unibo.it)were implemented successfully, nested within the forecasting model. The implementation exercise was carried out in different region/shelf dynamical regimes and it was demonstrated that one-way nesting is practical and accurate;7. Validation and calibration of a complex ecosystem model in data reach shelf areas, to prepare for forecasting in a future phase. The same ecosystem model is capable of reproducing the major features of the primary producers' carbon cycle in different regions and shelf areas. The model simulations were compared with the multidisciplinary M3A buoy observations and assimilation techniques were developed for the biochemical data.This paper overviews the methodological aspects of the research done, from the NRT observing system to the forecasting/modelling components and to the extensive validation/calibration experiments carried out with regional/shelf and ecosystem models.

The fidelity of corrections and processing are critical for a realistic use of official altimetric products close to the coast. A new processing strategy, which starts from the TOPEX/Poseidon GDRs with the addition of improved corrective terms, is proposed and evaluated in the area of the Corsica Channel. Sea level anomalies agree with the coincident sea truth (bottom pressure and tide gauge) within 2-3 cm rms for seasonal and longer time scales. Analysis for almost ten years of coincident mooring and altimetric velocities shows that a substantial reduction of uncertainty to ∼4 cm s−1 may be possible after reasonable filtering of the noise introduced by more variable coastal sea surface states. The conclusion is that the altimetry success is still limited to seasonal time scales, and provided that the oceanographic signal ensures an adequate signature to be isolated from background noise

No abstract

Abstract. In this paper we examine the relationship between the seasonal and interannual variability observed in the water flow through the Corsica Channel and the sea level difference between the Tyrrhenian and Ligurian Seas. The steric contribution to the sea level difference, computed from historical hydrological data, is in good agreement with the stable presence of the seasonal signal in the water exchanges. We obtain the maximum steric difference in winter (-16 cm) and the minimum in summer (-2 cm). These values are consistent with the corresponding estimates of water volume transport (0.8 and <0.1 Sv in winter and summer, respectively). Also, TOPEX/Poseidon (T/P) satellite altimetry is shown to be capable of capturing the sea level difference anomaly between the two basins at seasonal and interannual scales. Accuracy of altimeter data in the study region has been checked using measurements from a bottom pressure recorder deployed in Capraia Island (rms difference is found to be -2 cm after application of a 30-day half-amplitude Gaussian filter). Because of the lack of an accurate geoid, the total water transport cannot be adequately monitored by satellite altimetry alone. However, the recovered signal can be directly related to the water transport anomaly through the channel. The resulting T/P signal can be considered as representing, to a great extent, the real steric variation induced by the net sea surface heat