Climate Relevant Processes in the Ocean
Many processes in the climate system can only be investigated by a combination of theoretical observations and numerical simulations. Some examples of such processes, investigated at the IfM, are described here.
Historically, ship measurements represent an important observation foundation for Oceanography that accessed essential aspects of ocean water masses in the first half of the last century and enabled a description of the current systems. However, the limits of the naturally confined numbers of ship and mooring measurements became clear with advanced knowledge about the ocean dynamics, especially about the high-energy and nearly omnipresent internal wave fields and the turbulent, meso-scale vorticity fields. Hence, ‘classic’ measurements are increasingly supported by new measurement methods: On the one hand remote sensing from satellites and airplanes, that allow a large-scale, i.e. nearly global coverage of a steady growing number of parameters, and on the other hand by automatic measuring devices as e.g. ARGO-Floats or gliders. The increasing number of new measurement devices now allows a high-resolution view in the dark inner ocean, whereas remote sensing of radiation properties is mainly restricted to the upper ocean.
Manifold processes can be investigated and interpreted with these observations; but it isn’t obvious if and how they are relevant for climate. At our institute we work on, e.g. remote sensing of important sea ice parameters, that play a role in the radiation and heat balance of the Earth (next to clouds), but also on the possibility of using remote sensing for river discharge rates. Another topic investigated over the last decades is the overflow of Arctic Water into the Atlantic Ocean between Greenland, Iceland and Scotland, which plays a role for the development of water masses, next to the convection in the subpolar and subtropical Atlantic.
Convection and ventilation of the ocean plays a central part for biogeochemical processes, which are climate relevant not only through the uptake of solved carbon and the change in the radiation budget of the atmosphere, but also by manifold other processes. However, convection cannot be solved directly in numerical models, so a parameterization is used to integrate these processes into models. The effect on the primary production, but also the development of missing and the enhancement of existing parameterizations for other climate relevant processes, such as internal waves and (sub) meso-scale vortices are additional research topics of the Institute of Oceanography. A combination of theory, observations and numerical simulations are needed for this effort.
Written by Prof. Dr. Carsten Eden