Space and Time Distributions of Phosphate in the Mediterranean Sea (doppio con ART 90884)

Abstract not availableJRC.H-Institute for environment and sustainability (Ispra

Space and Time Distributions of Phosphate in the Mediterranean Sea.

Abstract not availableJRC.H-Institute for environment and sustainability (Ispra

Space and time distributions of phosphate in the Mediterranean Sea

Statistical modelling was applied to a large number of historical nutrient data to assess the significance of human perturbations in the Mediterranean Sea. All available phosphate data were grouped into subsets representative of averaged values of the measured vertical profiles in the surface and deep water layers. In contrast to earlier predictions, the statistical analysis of the phosphate concentrations in a deep water layer does not indicate any particular trend in time for the last 30 years. These data sets were then used as an input to an inverse model and a 3D primitive equation model (PEM). The former redistributes the measured concentrations by means of a variational principle and reconstructs average horizontal space distributions of the phosphate data fields as gridded solutions over the whole area. The spatial and temporal distributions thus obtained are visualised graphically and compared with other existing data, providing the first overall view of phosphate in the whole Mediterranean Sea and revealing an increasing oligotrophy towards the eastern basin. The primitive equation model is then used to assess the variability and upwelling fluxes.<br/

Space and Seasonal Distributions of Nitrates in the Mediterranean Sea Derived from a Variational Inverse Model.

Abstract not availableJRC.(EI)-Environment Institut

High-resolution Climatology of the northeast Atlantic using Data-Interpolating Variational Analysis (DIVA)

Numerous climatologies are available at different resolutions and cover various parts of the global ocean. Most of them have a resolution too low to represent suitably regional processes and the methods for their construction are not able to take into account the influence of physical effects (topographic constraints, boundary conditions, advection, etc.). A high-resolution atlas for temperature and salinity is developed for the northeast Atlantic Ocean on 33 depth levels. The originality of this climatology is twofold: (1) For the data set, data are collected on all major databases and aggregated to lead to an original data collection without duplicates, richer than the World Ocean Database 2005, for the same region of interest. (2) For the method, climatological fields are constructed using the variational method Data-Interpolating Variational Analysis. The formulation of the latter allows the consideration of coastlines and bottom topography, and has a numerical cost almost independent on the number of observations. Moreover, only a few parameters, determined in an objective way, are necessary to perform an analysis. The results show overall good agreement with the widely used World Ocean Atlas, but also reveal significant improvements in coastal areas. Error maps are generated according to different theories and emphasize the importance of data coverage for the creation of such climatological fields. Automatic outlier detection is performed, and its effects on the analysis are examined. The method presented here is very general and not dependent on the region, hence it may be applied for creating other regional atlas in different zones of the global ocean