Warnemünde Turbulence Days 2021
The ocean is bounded by two major interfaces at the surface and the bottom, both critically affected by the turbulent processes in the adjacent boundary layers. The fluxes of momentum and heat, and the gas exchange with the atmosphere, are communicated through the air-sea interface, controlled by surface-wave effects and turbulence in the oceanic and atmospheric boundary layers. Similarly, fluxes across the sediment-water interface are mediated by the turbulent structure of the bottom boundary layer, which determines the fluxes of momentum and dissolved substances (e.g., oxygen and nutrients), and controls the resuspension of sinking particles. In the context of climate change, turbulence in the vicinity of the ice-ocean interface (e.g., underneath sea ice and floating ice shelfs) has been shown crucial for the heat exchange and the associated melting rates. Also the interior of the ocean is structured by interfaces across a wide range of scales. Dynamically active interfaces are related to density stratification induced by thermoclines, haloclines, and lutoclines. Complex entrainment and detrainment processes occur at such pycnoclines, e.g. at the base of the surface mixed layer and the top of the bottom boundary layer. Pycnoclines are also known to host a wealth of internal waves that interact with each other and with turbulence, mediating the diapycnal fluxes of momentum, energy, and matter. The structure of dynamically inactive surfaces such as nutriclines, redoxclines, and thin plankton layers are also partly shaped by turbulent processes. On a large scale, the ocean may be imagined subdivided into various types of water masses defined by their thermohaline properties, where isohalines, isothermals or isopycnals are considered as surfaces that provide a framework for the analysis of water mass transformations driven by turbulent mixing. For the 10th Warnemünde Turbulence Days we invite contributions focusing on this year’s topic “Interfaces and turbulent boundary layers” across all oceanic scales. Related contributions from physical oceanography, atmospheric physics, meteorology, physical limnology, coastal engineering, and mathematics are highly welcome.