Marine biogeochemistry in the Flexible Ocean and Climate Infrastructure (FOCI)

Schematic of the marine biogeochemistry in FOCI. The model consists of the TRACY-MOPS model (TRAcer Calibrated cYcles | Model of Oceanic Pelagic Stoichiometry) and follows the OMIP5 protocol for the carbonate chemistry and air-sea gas fluxes.

Implementing a marine biogeochemistry model in the Flexible Ocean and Climate Infrastructure (FOCI) enables modelling of the global carbon cycle and studying bio-physical interactions at high spatial resolutions.

A marine biogeochemistry model, TRACY-MOPS (TRAcer Calibrated cYcles | Model of Oceanic Pelagic Stoichiometry), has been implemented into the Flexible Ocean and Climate Infrastructure (FOCI, see presentation by Jan Harlaß). With this implementation the global carbon cycle in FOCI is closed and we can study not only climate carbon cycle interaction but also marine biology climate interactions at the comparatively high resolution that FOCI provides (~1.8° horizontal resolution in the atmosphere model and 0.5° in the ocean model).
MOPS describes marine biology in terms of cycling nutrients (phosphate and nitrate), phytoplankton, zooplankton, detritus, and dissolved inorganic matter (Kriest and Oschlies 2015). Optimal values and uncertainty envelopes have been determined for the biogeochemical parameters via calibration against climatologies of observed macronutrients and oxygen (Kriest 2017; Kriest et al. 2017). The parameters have been further adjusted in an implementation of TRACY-MOPS in NEMO (the ocean model component of FOCI).
Sea-air gas exchanges, for oxygen and carbon dioxide, follow the Ocean Model Intercomparison Project protocol (Orr et al. 2017). The carbonate chemistry description is also based on Orr et al. 2017 and on Orr and Epitalon (2015), with the main deviation being that pH is not calculated iteratively but using a simplified and computationally-efficient method (Follows et.al. 2006).
The global distribution of air-sea carbon dioxide aligns with observations in first trial simulations. A spin-up simulation under pre-industrial conditions is running.

References

Kriest, I., A. Oschlies. 2015. “MOPS-1.0: Towards a Model for the Regulation of the Global Oceanic Nitrogen Budget by Marine Biogeochemical Processes.” Geoscientific Model Development

Kriest, I. 2017. “Calibration of a Simple and a Complex Model of Global Marine Biogeochemistry.” Biogeosciences

Kriest, I., V. Sauerland, S. Khatiwala, A. Srivastav, A. Oschlies. 2017. “Calibrating a Global Three-Dimensional Biogeochemical Ocean Model (MOPS-1.0).” Geosci. Model Dev.

Follows, M. J. et.al. 2006. “On the Solution of the Carbonate Chemistry System in Ocean Biogeochemistry Models.” Ocean Modelling

Orr, J. C. et al. 2017. “Biogeochemical Protocols and Diagnostics for the CMIP6 Ocean Model Intercomparison Project (OMIP).” Geosci. Model Dev.

Orr, J. C., J. M. Epitalon. 2015. “Improved Routines to Model the Ocean Carbonate System: Mocsy 2.0.” Geosci. Model Dev.

FOCI references:

Matthes, K. et.al., FOCI reference paper, in prep.

Stevens, B., et.al., 2013, “Atmospheric component of the MPI-M Earth System Model: ECHAM6”, Journal of Advances in Modeling Earth Systems

Schultz, M. G., et.al., 2018, “The chemistry–climate model ECHAM6.3-HAM2.3-MOZ1.0”, Geosci. Model Dev.

Brovkin, V. et.al. 2009, Global biogeophysical interactions between forest and climate, Geophys. Res. Lett.

Reick, C. H., et.al., 2013, “Representation of natural and anthropogenic land cover change in MPI-ESM”, Adv. Model. Earth Sy.

Madec, G., 2016, “NEMO ocean engine”, Note du Pôle modélisation, Inst. Pierre-Simon Laplace.

Dana's research centers on Earth system modelling, with particular focus on carbon cycle climate feedbacks. Specifically, she investigates the relationship between global mean temperature change and cumulative CO2 emissions, the role of ocean heat and carbon uptake in the Earth system, and the effects on the Earth system from carbon dioxide removal.