Data presented here were collected between November 2019 to September 2023 within the research unit DynaCom (Spatial community ecology in highly dynamic landscapes: From island biogeography to metaecosystems, https://uol.de/dynacom/ ) involving the Universities of Oldenburg, Göttingen, and Münster, the iDiv Leipzig and the Nationalpark Niedersächsisches Wattenmeer. Experimental islands and saltmarsh enclosed plots were established in the back-barrier tidal flat and in the saltmarsh zone of the island of Spiekeroog (Germany). A recording current meter (RCM; SEAGUARD® Recording Current Meter, Aanderaa Data Instruments AS, Bergen/Norway) was installed in the back-barrier tidal flat near the experimental islands. The sensor was bottom-mounted in a shallow tidal creek (0.59 m NHN) using a steel girder buried in the sediment, which caused the sensor to be exposed during low tide. All low-tide data have been removed from the dataset. The system was equipped with a ZPulse Doppler Current Sensor (DCS), a conductivity sensor, an oxygen optode, and two analogue sensors for chlorophyll-a and turbidity (16445). All sensors were pre-calibrated by the manufacturer. Recorded data were internally logged until readout with the SeaGuard Studio software (V1.5.23). Salinity was derived in the SeaGuard Studio software using temperature-dependent, nonlinear seawater conductivity compensation following the Practical Salinity Scale (PSS-78). Subsequent data processing was done using MATLAB (R2024b). Turbidity and chlorophyll-a data were excluded from the final dataset, as the recorded signals show implausible values and did not pass quality-control criteria. Post-processing and quality control included (a) the removal of low tide data, data covering maintenance activities, and data affected by biofouling, (b) the removal of implausible values, c) an outlier detection using the Hampel filter method, and (d) visual checks. Identified outlier were removed and synchronously removed across all associated parameters of the respective sensor.
The upper-ocean circulation of the tropical Atlantic is a complex superposition of thermohaline and wind-driven flow components. The resulting zonally- and vertically-integrated upper-ocean meridional flow is referred to as the upper branch of the Atlantic Meridional Overturning Circulation (AMOC) - a major component and potential tipping element of the global climate system. We investigate the tropical part of the northward AMOC branch, i.e. the return flow covering the upper 1,200 m, based on Argo data and repeated shipboard velocity measurements. The western boundary mean circulation at 11°S is realistically reproduced from high-resolution Argo data showing a remarkably good representation of the vertical structure of meridional velocity and the volume transport of water mass layers when compared to results from direct velocity measurements along a repeated ship section. Thus, we extend the analysis to the inner tropical Atlantic. Within the AMOC return flow, a diapycnal upwelling of central water into the thermocline layer of ~2 Sv is derived between 11°S and 10°N which is about half the magnitude of previous estimates, likely due to improved horizontal resolution. The mean strength of the AMOC return flow is ~16 Sv across 11°S and 10°N. At 11°S, northward transport is concentrated at the western boundary where the AMOC return flow enters the tropics at all vertical layers above 1,200 m. At 10°N, northward transport is observed both at the western boundary and in the interior predominantly in the surface and intermediate layer indicating recirculation and transformation of thermocline and central water within the tropics.
To unterstand the discharge pathes of the river Odra and to verify numerical models, hydrographic and meteorological measurements are carried out in the Odra lagoon. 3 fixed stations (2 piles and a pontoon in the Kleines Haff) measure the following parameters: Current (2 components), sea level and wave height, pressure at sensor level, water temperature, turbidity, conductivity, fluorescence, wind speed, wind direction, air temperature, atmospheric pressure. A wave-rider buoy in the Kleines Haff delivers statistic wave data. In 1998 two sea bottom bound ADCPs are continuously measuring currents in the west and east part of the Kleines Haff. The research vessel Ludwig Prandtl undertakes measuring cruises. It is equipped with an ADCP for current/water transport measurements and a CTD profiler for current, turbidity, fluorescence and oxygen measurements.