PhD defence of Mira Schmit: Diurnal Warm Layers in the Ocean: Dynamics, Turbulence and Atmospheric Feedbacks

Abstract
Small-scale physical processes in the ocean surface layer govern the energy exchange at the airsea interface and play a crucial role in the distribution of momentum, energy and tracers in the ocean. However, they are usually not directly resolved in climate models due to limited computational resources. This dissertation investigates Diurnal Warm Layers (DWLs), which are thin, buoyant layers that form on the surface of the ocean on days with weak surface wind and waves due to heating by the sun. Based on high-resolution models, the interplay of DWLs with surface waves and fronts is investigated. Moreover, the impact of precipitation, cold pools and wind bursts on the ocean surface layer is analysed and feedback mechanisms with the atmosphere are highlighted.  DWLs are shown to significantly modify oceanic mixing and increase the heat flux exchange with the atmosphere