Retrospective analyses of physical boundary conditions and biogeochemical cycles

Work under this theme is to describe, analyse and model past states of the physical boundary conditions and biogeochemical regimes imposed by regional climate. This entails the identification of typical circulation patterns at given extremes in wind forcing, as well as concomitant redox states of shelf waters and their relationship to nutrient element levels and inter-element ratios by analysis of available (SADCO data bank) and new data collected during 4 expeditions (2008, 2010).

Driven by available climate re-analysis and satellite data, and synthetic forcing by a regional climate model (REMO) downscaled from a global simulation (the Millennium-simulation of MPI for Meteorology, Hamburg), a circulation model (MOM4) coupled to an ecosystem model (ERGOM, simulating nutrients, phytoplankton, zooplankton and detritus) will be calibrated and used to simulate ecosystem structures and material flows at historical extremes in climate forcing (retrospective analysis). The fluxes of radiatively active gases, and transports of nutrient elements and carbon between the coastal ocean, the adjacent mesopelagic ocean, the atmosphere, and sediments will be assessed and scaled to given atmospheric and oceanic circulation states.