Physical oceanography from eight Seaglider missions in the Mediterranean Sea, Eastern Basin

In 2008, the Oceanography Center at the University of Cyprus acquired two underwater gliders in the framework of a nationally-managed infrastructure upgrade program. The gliders were purchased from the Seaglider Fabrication Center at the University of Washington. Both gliders are rated to 1000 m and carry a typical sensor payload: non-pumped conductivity-temperature-depth sensors (CTD), a dissolved oxygen sensor, an optical triplet to measure optical backscatter at 400 nm, 700 nm, and chlorophyll-a fluorescence. Since March of 2009, the gliders have been used in a long-term observing program of the Cypriot EEZ, and by September 2015, have covered more than 15300 km over ground and 3500 dive cycles in 940 glider days. Butterfly patterns have been flown in two configurations, either on the western or eastern side of the EEZ south of Cyprus. The glider endurance lines criss-cross the region in order to more accurately locate and investigate the mesoscale structures south of Cyprus, and in particular the Cyprus eddy which is often the dominant feature. Based on the near real time observations, the glider mission was sometimes altered in order to more fully sample the Cyprus eddy, or to locate its center or extent. A summary of the raw and processed data collected, and the quality control procedures are presented, in order for future users to take advantage of this unique data set.

Physical oceanography during POLARSTERN cruise ANT-XII/4

The report presents the results of the CTD measurements carried out in the Bellingshausen Sea - an area rare of CTD measurements. The main part of the report consists of the brief description of the CTD data acquisition and processing routines, the vertical profiles of temperature, salinity and density, and of the plots of the distribution of these properties along the hydrographic sections. The final part of the report deals with the notably similar structure of the vertical density distribution at different locations if presented as a function of a non dimensional vertical co-ordinate. It is pointed out that such a distribution could be an asymptotic limit of stationary mixing along neutral surfaces.

Physical and acoustic sediment properties of sediment cores from the eastern equatorial Atlantic

To reconstruct the deep-water circulation for the last 3.5 Ma from deep-sea sediments of the eastern equatorial Atlantic, sea floor morphology, sub-bottom reflectors and the echo character have been mapped on the basis of 3.5 kHz records and sediment cores. Physical properties of sediments and synthetic seismograms derived from them enable us to decipher reflector sequences in environments of pelagic, current-resuspended and turbidity sedimentation. The individual reflectors originate from carbonate dissolution, hiatus, coarse sand layers and interferences. Those which are related to carbonate dissolution and hiatus provide evidence of water-mass boundaries by their distribution. Five phases of different deep-water circulation can be seen in the record of th elast 3.5 Ma, and these are related to climate history: 1. Between 3.7 Ma and 2.2 Ma a strong deep-water circulation indicates a northward flow of bottom water below 4200 m (AABW = Antarctic-Bottom Water) and a southward flow of deep-water above 4200 m (NADW = North-Atlantic Deep Water). 2. Between 1.6 and 1.4 Ma a southward flow of bottom water below 4500 m and a diminished southward flow above 4500 m can be detected. This water-mass geometry can be interpreted by an expansion of the NADW-masses and a displacement of the AABW-masses during the same time. 3. Since 1.4 Ma a northward flow of a bottom-water current developed again. This current flow created a leeside sediment ridge in the southern part of the Kane Gap and furrows in the northern part of it. 4. Between 400,000 and 200,000 yrs B. P. the oceanic and atmospheric circulation increased. The strengthened oceanic circulation caused and increase in carbonate dissolution, which is documented by a traceable reflector from 2800 m to 4500 m water depth. At the same time an increase of the atmospheric circulation caused a drastic rise in the pelagic sediment accumulation (> 100 %) through an intensification of upwelling. This runs parallel with a higher oceanic productivity in the northern equatorial divergence zone and an enhanced supply of fluvial and probably eolian sediments from the Senegal and Guinea. 5. Before 10,000 yrs B. P. an erosive northward flowing bottom-water current prevailed below 4500 m water depth. After 10,000 yrs B.P. the bottom-water flow was sluggish and non erosive.

Short-term temporal and spatial variations in physical, optical and biogeochemical parameters in June of 2013 in Alfacs Bay (NW Mediterranean)

With the aim of analyzing the complex physical and biogeochemical interactions at high temporal and spatial resolution in the complex estuarine waters of Alfacs Bay, a beam attenuation-based approach was used as optical proxy of different biogeochemical variables. Thus, the dataset contains the attenuation proxies as well as laboratory results from the analysis of water samples, which were used to validate our approach. In addition, the major physical forcing in the Bay was also measured.