PLUME
| Type | Oceanographic cruise |
|---|---|
| Ship | Côtes De La Manche |
| Ship owner | CNRS until 2019 - IFREMER since 2020 |
| Dates | 20/05/2016 - 29/05/2016 |
| Chief scientist(s) | LAZURE Pascal  |
LABORATOIRE D'OCÉANOGRAPHIE PHYSIQUE ET SPATIALE - UMR 6523 Centre Ifremer Bretagne ZI Pointe du Diable CS 10070 29280 Plouzané +33 (0)2 98 22 42 76 |
|
| DOI | 10.17600/16009800 |
| Objective | This cruise is a complement to the opportunity sampling done during already-scheduled cruises, in particular, fisheries stock assessment cruises like PELGAS. It should clarify the mixing processes of water masses in coastal areas. Two dedicated cruises have been planned to refine knowledge about processes in these key zones. Prior to these cruises, special effort is devoted to knowledge about the tritium term sources from the Loire and Gironde rivers. Daily measurements will be taken at the mouths at least six months before the cruises to accurately characterize the tritium fluxes at the start of tagging and make it possible to compare the quantities of simulated and measured radionuclides on the scale of the Bay. The cruises' specific objectives are to: Describe tritium's distribution and variability in the Bay of Biscay. Specify the areas of plume dispersal (Loire, Gironde) and the characteristics of horizontal and vertical dilution from the mouths; Estimate the time of stay (or renewal) of fresh water on the shelf of the Bay of Biscay using precise quantitative assessments; Confirm and refine the image of river plumes to highlight mixing processes and zones between the plumes and evaluate the respective contributions of inflows to zones adjacent to the large estuaries (Bay of Bourgneuf, Bay of Vilaine and Pertuis Charentais); Use the specific and differentiated chronologies of discharges from the Loire and the Gironde (factor 3) to estimate the areas of influence of these two large plumes and validate the dispersal processes represented by models (especially along the Vendée coast). The cruises already scheduled in 2016 cover the entire Bay of Biscay. The TRIGASC cruise will focus on describing river plumes on a smaller scale and their interaction between the Loire and the Gironde. |
