Burkard Baschek - Research

Submesoscale eddies and fronts are a likely route for energy transport from the large-scale ocean circulation to turbulence and are also closely linked to biological and biogeochemical processes. This is, for example, visible in ocean color and sea surface temperature in the upwelling regime off the coast of California, but also in mid-ocean eddies. Due to their short life time of several hours to a few days and small spatial scales of 10 m to 10 km, submesoscale features are very transient in nature and hard to measure, so that only few measurements exist that truly resolve these features. We are using quasi-synoptic aerial measurements of SST from a small aircraft to guide and complement towed hydrographic in situ observations. These measurements are complemented by SAR satellite, drifter and surfactant data. (Details)

Rogue Waves are unexpected waves that are more than twice as high as the significant wave height and can be extremely destructive for vessels or off-shore platforms. The coastal ocean offers a natural laboratory to study the formation of these waves, especially in areas of wave-current interaction. We have investigated 100 years of wave buoy to study the likelihood of rogue wave occurrence and the directionality of rogue waves relative to the main wave direction. (Details)

The understanding of air-sea gas exchange is important for the coastal and global ocean (e.g. oxygen depletion, greenhouse effect). Direct bubble measurements are combined with indirect measurements of dissolved gases in order to use dissolved gas concentrations as “fingerprint” of the entrainment mechanisms by utilizing the different physical and chemical properties of the gases. In this respect, especially the noble gases are of importance as they are not connected to biogeochemical cycles.

To collect accurate long-term time-series measurements of all noble gases a Noble Gas Sampler (designed by D. Lott & W. Jenkins, WHOI) has been further developed and deployed off Bermuda. The results will be used for an improved and more physical parameterization of air-sea gas exchange that can be used by the global and coastal modeling community. For this purpose, a “bulk model” of gas bubble behavior was developed. (Details)

Flow-Topography Interaction & Tidal Fronts

The Fraser Estuary, BC, Canada, is a region of pronounced flow-topography interaction. Several tidal fronts develop around the islands of Haro Strait due to strong tidal currents. Especially the strong hydraulic flow over a sharp sill at Boundary Pass proved to be of importance for the gas ventilation of intermediate water in the Strait of Georgia – a process that may be of significance to many estuaries with strong tidal currents. The flow over the sill is characterized by an arrested upper layer and intense detrainment of dense fluid with mixing rates of up to 60%. (Details)

Extreme Tidal Environments

Brief measurements of sea surface elevation, currents, and energy dissipation have been carried out in the extreme tidal environments of British Columbia, Canada (Dent, Arran, and Nakwakto Rapids). (Details)

Strait of Gibraltar

Extensive ship-board measurements of hydrography and currents were carried out in the Strait of Gibraltar as part of the international EU-project CANIGO (Canary Island Azores Gibraltar Observations; Uwe Send, IfM Kiel). A newly developed tidal inverse model provided accurate transport estimates through the Strait. These results were also used as comparison for acoustical tomography measurements during the same experiments. The work also focused on the dynamics of the hydraulically controlled exchange flow. (Details)

Water Mass Formation in the Red Sea

The Gulf of Aqaba respresents an important source of bottom water in the Red Sea. This was shown in February 1999 by hydrographic ship-board measurements in combination with an analysis of the chlorofluorocarbon component CFC-12. (Details)