Coupling MEDUSA Sediment model to iLOVECLIM (v1.1β) Earth system model

Due to the strong interactions between atmospheric CO2 and the evolution of climate, carbon cycle models are needed as part of climate models. CO2 influences the Earth's Energy budget which affects global temperatures and, while temperature affects solubility of CO2 in the ocean which affects global carbon storage in the ocean (38700 x 10^15 gC) and ocean floor surface sediments (1750 x 10^15 gC). Dissolved CO2 also affects Carbonate Compensation Depth (CCD) which may lead to chemical erosion of sediments and release of buried carbonates providing an extra source of dissolved inorganic carbon and total alkalinity into the ocean. One of the objectives of the ACCLIMATE Project (sea.acclimateproject.eu) is the simulation of rapid climate changes during the last 40 ky and, therefore, it is necessary to properly simulate the CCD by including sediments as one of the main components of the ocean carbon cycle. MEDUSA sediment model has been coupled with the intermediate complexity model iLOVECLIM to complement the previous implementation of an ocean carbon cycle module (OCYCC). Fluxes and concentrations are exchanged between the bottom layer of the OCYCC module and the reactive surface layer of MEDUSA sediment column through wrapper modules which act as interface, keep consistency in the units and preserve mass balance. A numerical simulation has been performed to reach equilibrium for deep ocean variables and sediments and the results have been compared to World Ocean Atlas 2013 and GLODAP v2 data.