Volker Mohrholz (Leibniz Institute for Baltic Sea Research Warnemünde Dept. of Physical Oceanography and Instrumentation, Germany); Jürgen Kusche (University of Bonn, Institute of Geodesy and Geoinformation, Germany)

The CONWEST-DYCO project aims to detect fine scale variability and hydrodynamic processes with space observations of high spatial resolution. Two research questions are addressed:
Can we observe sub-mesoscale structures and hydrodynamic processes? Can we track the water exchange?
Selected for this analysis are two regions in the Baltic Sea: the Easter Gotland Basin (EGB) and the Danish Straits.
The first is a key area for studying oceanic processes that connect deep-water and surface layer, with long-term circulation in EGB characterized by a basin scale cyclonic gyre of radius 25-35 km with a mean current velocity of 5 to 10 cm/s.
In the second area, the Danish Straits, the transport is driven by sea level differences and flow is driven by barotropic pressure gradient. Fine scale processes like upwelling, mesoscale frontal structure and sub-mesoscale filaments are superposed to the general estuarine circulation.

The variabilities of sea level heights and current velocities are measured by nadir- and swath satellite altimetry.
Comparison with multi-mission nadir-altimeters evaluate the additional information contained in the swath-altimeter data. An in situ campaign experiment on the ground track segment of the SWOT fast sampling phase orbit in central Baltic uses diagnostics to detect currents, transport, and mixing properties from auxiliary observations of sea surface temperature, chlorophyll and ocean colour parameters and is part of this activity.