The model is relevant specifically for GENUS Theme 4) Simulations of interactions between shelf ecosystem – open ocean – atmosphere

In this theme, GENUS will use/ adapt/improve existing model components and create new components to gauge the range of natural variations in the upwelling shelf pump for CO2 and nutrients under natural and man-made climate variability. Central goal of this theme is a quantitative estimate of natural ranges in mass fluxes between the shelf system and the adjacent mesopelagic ocean, as well as ocean-atmosphere fluxes of CO2 and methane. This requires a differentiation between variability in structures and functioning of the upwelling ecosystem attributable to climate forcing, and to fisheries. Time windows for retrospective simulations are the period 1960-2008 AD, for which observational data exist for all ecosystem components, as well as two extremes in global climate of the last 1000 years: The Little Ice Age (LIA) during the Maunder sunspot minimum (1670-1710 AD) and the Medieval Warm Period (MWP; 1130-1170 AD). In these experiments, synthetic climate forcing is simulated by a regional climate model (REMO) downscaled from a global Earth System Model (the Millennium simulation of MPI for Meteorology in Hamburg) and is passed on to a regional setup of MOM4/ERGOM, which will also use oceanic boundary conditions from the Millennium simulation. The modelled patterns of primary producers simulated by ERGOM are used to drive ECOPATH/ECOSIM energy balances of the higher trophic levels, which then are used to modify ERGOM in order to gauge effects of changing trophic structures on material cycles.