Objectif The project aims to(i) improve understanding and modelling of dense water overflows, e.g. "cascading" as a meso-scale process;(ii) extrapolate from specific observations (focused on the edge of the continental shelf) using generic models and;(iii) estimate its influence on fluxes of dissolved and particulate matter between the shelf and open ocean in the bottom boundary layer.This will be carried out by:- collating existing confirmed observations of cascading, and data of relevant laboratory experiments, to provide a common data base for modelling;- searching relevant oceanographic data banks (eg. BODC, ICES, NODC, EWG Arctic Ocean database) and collating wider data relevant to cascading (eg. identify regions and timing of dense shelf water mass formation);- disseminating collated cascade data in a suitable form (eg. CD-ROM);- systematically analysing these data for cascading; by inter-comparison, identifying factors and mechanisms contributing to and influencing pre-conditioning, initiation, the evolving form and the end-stages of dense water overflow.Factors to be sought by analysis include: sources of density difference (suspended sediment; increased salinity during ice formation; increased salinity in an along-slope current, which may leak on to the shelf at particular locations, e.g. where the slope is steep; winter cooling of shallow shelf waters); down-slope Ekman flow under a slope current (stronger where the slope is steeper); wind-forced down-welling; topographic features. A distinction will be made between initiating (instability) factors and those controlling the subsequent amount of cascading.Further means to carry out the project aims will be:- identifying processes to be modelled;- developing a linked set of new or modified models capable of simulating the main driving mechanisms and predicting better the characteristics of cascading: 1.5-layer; primitive-equation layered; axisymmetric 2-D primitive-equation conical; sliced 2-D plane, semi-geostrophic and primitive-equation; 3-D full-physics, in some cases with suspended sediment;- inter-comparing the different modelling approaches and checking the models against the data sets; assessing the ability of the models to reproduce the evolution, main features (e.g. depth of penetration, degree of entrainment) and end stages of dense water overflows; identifying improvements, scope for unifying models or the need for new model development;- developing the 3D hydrodynamic model to study the generation and movement of mudslides that the cascading process can initiate (trigger) if sediment material becomes unstable over a steep bottom slope. The mudslide will be treated as a viscous flow, with characteristics that vary with 2D bottom topography, coupled with the water flow. In addition a non-Newton liquid Bingham model will be used to study instability and movement of the sediment (mud) body;- estimating cascading fluxes of water masses, dissolved and particulate matter between the shelf and ocean using the observational data and models;- estimating the climatological influence of shelf-edge cascading.Expected results are: systematic collation of relevant cascading data sets; results and comparisons of simulations thereof with a range of models; information on the interannual variability of conditions suitable for cascading; a "1.5-layer" specifically-designed model, and output over bathymetric features; dissemination by World Wide Web and scientific publications; collated data distributed on CD-ROMs. Programme(s) IC-INTAS - International Association for the promotion of cooperation with scientists from the independent states of the former Soviet Union (INTAS), 1993- Thème(s) 5 - Earth Sciences, Environment, Energy OPEN - OPEN Call Appel à propositions Data not available Régime de financement Data not available Coordinateur Natural Environment Research Council Contribution de l’UE Aucune donnée Adresse Bidston Observatory CH43 7RA Wirral Royaume-Uni Voir sur la carte Coût total Aucune donnée Participants (8) Trier par ordre alphabétique Trier par contribution de l’UE Tout développer Tout réduire A.V. Luikov Heat and Mass Transfer Institute Biélorussie Contribution de l’UE Aucune donnée Adresse ul. P.Brovki, 15 220072 Minsk Voir sur la carte Coût total Aucune donnée Council of Research Italie Contribution de l’UE Aucune donnée Adresse 1364, S. Polo 30125 Venezia Voir sur la carte Coût total Aucune donnée Russian Academy of Sciences Russie Contribution de l’UE Aucune donnée Adresse Nakhimovsky prospect, 36 117851 Moscow Voir sur la carte Coût total Aucune donnée Russian State Hydrometeorological University Russie Contribution de l’UE Aucune donnée Adresse Maloohtinsky 98 195196 St. Petersburg Voir sur la carte Coût total Aucune donnée Scientific Coordination Center Russie Contribution de l’UE Aucune donnée Adresse Nakhimovski prospekt, 36 117851 Moscow Voir sur la carte Coût total Aucune donnée State Scientific Center of the Russian Federation Russie Contribution de l’UE Aucune donnée Adresse av. Beringa 38 199397 St. Petersburg Voir sur la carte Coût total Aucune donnée UNIVERSITY OF PLYMOUTH Royaume-Uni Contribution de l’UE Aucune donnée Adresse DRAKE CIRCUS PLYMOUTH Voir sur la carte Coût total Aucune donnée Universität Hamburg Allemagne Contribution de l’UE Aucune donnée Adresse Troplowitzstrasse 7 22529 Hamburg Voir sur la carte Coût total Aucune donnée
