General Information: The overall objective of the VEINS proposal reads: To measure and to model the variability of fluxes between the Arctic Ocean and the Atlantic Ocean with a view on implementing a longer term system of critical measurements needed to understand the high latitude oceans steering role in decadal climate variability. Exchanges between the North Atlantic and the Arctic Ocean result in the most dramatic water mass conversions in the World Ocean: Warm and saline Atlantic waters flowing through the Nordic Seas into the Arctic Ocean are separated by cooling and freezing into shallow fresh waters (and ice) and saline deep waters. The outflow from the Northern Seas to the south provides the initial driving of the global thermohaline circulation cell, the one to the north is of major impact to the large scale circulation of the Arctic Ocean Measuring these fluxes is a major requirement to quantify the turnover-rates within the large circulation cells of the Arctic and the Atlantic Oceans and a basic condition to understand the role of these ocean areas in climate variability on interannual to decadal scales. For this purpose a consortium of 18 institutions with long standing experience in high latitude observations and modelling propose to obtain 3 year synoptic time series of water and property transports in the key passages from the Arctic Ocean through the Nordic Seas into the Atlantic Ocean. These measurements will provide integral information on the water mass formation processes in the Northern Seas and on the forces driving the circulation between the different basins. This makes them especially suitable for the validation of large scale circulation models. Its results will be used to develop an efficient observational design to measure time series resolving up to decadal time scales, which are considered to be the most cirucial measurements for advancing our predictive capabilities for shorter term climate changes. Prime Contractor: Universität Hamburg, Zentrum für Meeres- und Klimaforschung, Institut für Meereskunde; Hamburg; Germany.
Fragestellungen aus zwei unterschiedlichen Regionen des Atlantischen Ozeans sollen bearbeitet werden: 1) Die Besonderheit des aequatorialen Stromsystems ist in der Tatsache begruendet, dass mit dem Verschwinden der ablenkenden Kraft der Erdrotation die nicht-linearen Anteile des Kraeftesystems die Kompensation der Druckgradientkraefte uebernehmen. Das aeussert sich in einem System von meridionalen Zirkulationszellen, deren aequatoriale Konvergenzen bzw. Divergenzen zu charakteristischen meridionalen Salzgehaltstrukturen fuehren. Aus den waehrend 'FGGE Aequator '79' gewonnenen meridionalen hydrographischen Schnitten soll die mit dem aequatorialen Unterstrom veraenderliche Struktur der Zirkulationszellen analysiert werden. 2) Zwei hydrographische Datensaetze aus dem europaeischen Nordmeer (Spaetsommer '79, Spaetwinter '82) sollen dafuer verwendet werden, die Salzzufuhr in die Gebiete der Tiefwasserbildung noerdlich von Jan Mayen und auf dem Barents-Schelf zu analysieren. Schwankungen des Verhaeltnisses der Salzzufuhr durch den nordatlantischen Strom/Norwegenstrom in die einzelnen Regionen gelten als Ursache fuer die unterschiedliche Intensitaet der Tiefwasserbildung.