Coupling of a sediment diagenesis model (MEDUSA) and an Earth system model (CESM1.2): a contribution toward enhanced marine biogeochemical modelling and long-term climate simulations

Abstract. We developed a coupling scheme for the Community Earth System Model version 1.2 (CESM1.2) and the Model of Early Diagenesis in the Upper Sediment of Adjustable complexity (MEDUSA), and explored the effects of the coupling on solid components in the upper sediment and on bottom seawater chemistry by comparing the coupled model's behaviour with that of the uncoupled CESM having a simplified treatment of sediment processes. CESM is a fully coupled atmosphere–ocean–sea-ice–land model and its ocean component (the Parallel Ocean Program version 2; POP2) includes a biogeochemical component (the Biogeochemical Elemental Cycling model; BEC). MEDUSA was coupled to POP2 in an offline manner so that each of the models ran separately and sequentially with regular exchanges of necessary boundary condition fields. This development was done with the ambitious aim of a future application for long-term (spanning a full glacial cycle; i.e. ∼105 years) climate simulations with a state-of-the-art comprehensive climate model including the carbon cycle, and was motivated by the fact that until now such simulations have been done only with less-complex climate models. We found that the sediment–model coupling already had non-negligible immediate advantages for ocean biogeochemistry in millennial-timescale simulations. First, the MEDUSA-coupled CESM outperformed the uncoupled CESM in reproducing an observation-based global distribution of sediment properties, especially for organic carbon and opal. Thus, the coupled model is expected to act as a better “bridge” between climate dynamics and sedimentary data, which will provide another measure of model performance. Second, in our experiments, the MEDUSA-coupled model and the uncoupled model had a difference of 0.2 ‰ or larger in terms of δ13C of bottom water over large areas, which implied a potentially significant model uncertainty for bottom seawater chemical composition due to a different way of sediment treatment. For example, an ocean model that does not treat sedimentary processes depending on the chemical composition of the ambient water can overestimate the amount of remineralization of organic matter in the upper sediment in an anoxic environment, which would lead to lighter δ13C values in the bottom water. Such a model uncertainty would be a fundamental issue for paleo model–data comparison often relying on data derived from benthic foraminifera.

[1]  M. Schulz,et al.  Newly developed model code and scripts for the coupling of CESM1.2 and MEDUSA , 2019 .

[2]  J. Middelburg,et al.  The role of calcification in carbonate compensation , 2018, Nature Geoscience.

[3]  M. Losch,et al.  A Dynamical Reconstruction of the Global Monthly Mean Oxygen Isotopic Composition of Seawater , 2018, Journal of Geophysical Research: Oceans.

[4]  V. Brovkin,et al.  Simulation of climate, ice sheets and CO 2 evolution during the last four glacial cycles with an Earth system model of intermediate complexity , 2017 .

[5]  Guy Munhoven,et al.  Understanding the causes and consequences of past marine carbon cycling variability through models , 2017 .

[6]  Takasumi Kurahashi-Nakamura,et al.  Dynamical reconstruction of the global ocean state during the Last Glacial Maximum , 2017 .

[7]  Sylvain Watelet,et al.  A new global interior ocean mapped climatology: the 1° × 1° GLODAP version 2 , 2016 .

[8]  P. Heimbach,et al.  Ocean Data Assimilation in Support of Climate Applications: Status and Perspectives. , 2016, Annual review of marine science.

[9]  F. Joos,et al.  A probabilistic assessment of calcium carbonate export and dissolution in the modern ocean , 2015 .

[10]  R. Müller,et al.  Census of seafloor sediments in the world’s ocean , 2015 .

[11]  Peter E. Thornton,et al.  Preindustrial-Control and Twentieth-Century Carbon Cycle Experiments with the Earth System Model CESM1(BGC) , 2014 .

[12]  K. Lindsay,et al.  Carbon isotopes in the ocean model of the Community Earth System Model (CESM1) , 2014 .

[13]  David A. Siegel,et al.  Global assessment of ocean carbon export by combining satellite observations and food‐web models , 2014 .

[14]  Xiaofeng Yang,et al.  Estimation of Marine Primary Productivity From Satellite-Derived Phytoplankton Absorption Data , 2014, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

[15]  Corinne Le Quéré,et al.  Carbon and Other Biogeochemical Cycles , 2014 .

[16]  Scott C. Doney,et al.  Marine Ecosystem Dynamics and Biogeochemical Cycling in the Community Earth System Model [CESM1(BGC)]: Comparison of the 1990s with the 2090s under the RCP4.5 and RCP8.5 Scenarios , 2013 .

[17]  W. Collins,et al.  Evaluation of climate models , 2013 .

[18]  Thomas R. Anderson,et al.  MEDUSA-2.0: an intermediate complexity biogeochemical model of the marine carbon cycle for climate change and ocean acidification studies , 2013 .

[19]  W. Collins,et al.  The Community Earth System Model: A Framework for Collaborative Research , 2013 .

[20]  A. Ridgwell,et al.  Marine Ecosystem Responses to Cenozoic Global Change , 2013, Science.

[21]  P. Tréguer,et al.  The world ocean silica cycle. , 2013, Annual review of marine science.

[22]  J.,et al.  Marine EcosystemDynamics and Biogeochemical Cycling in the Community Earth System Model [ CESM 1 ( BGC ) ] : Comparison of the 1990 s with the 2090 s under the RCP 4 . 5 and RCP 8 . 5 Scenarios , 2013 .

[23]  J. Toggweiler,et al.  Global calcite cycling constrained by sediment preservation controls , 2012 .

[24]  G. Danabasoglu,et al.  The Low-Resolution CCSM4 , 2012 .

[25]  Richard Sanders,et al.  Global patterns in efficiency of particulate organic carbon export and transfer to the deep ocean , 2012 .

[26]  Mariana Vertenstein,et al.  A new flexible coupler for earth system modeling developed for CCSM4 and CESM1 , 2012, Int. J. High Perform. Comput. Appl..

[27]  P. Naik,et al.  Simple equations to estimate ratios of new or export production to total production from satellite‐derived estimates of sea surface temperature and primary production , 2011 .

[28]  V. Brovkin,et al.  Glacial CO2 cycle as a succession of key physical and biogeochemical processes , 2011 .

[29]  Carolien Kroeze,et al.  Global river nutrient export: A scenario analysis of past and future trends , 2010 .

[30]  J. Middelburg,et al.  Ongoing transients in carbonate compensation , 2010 .

[31]  Heinrich Widmann,et al.  Climate and carbon-cycle variability over the last millennium , 2010 .

[32]  F. Joos,et al.  Deep ocean ventilation, carbon isotopes, marine sedimentation and the deglacial CO 2 rise , 2010 .

[33]  Carolien Kroeze,et al.  Global Nutrient Export from WaterSheds 2 (NEWS 2): Model development and implementation , 2010, Environ. Model. Softw..

[34]  A. Ridgwell,et al.  Response of deep‐sea CaCO3 sedimentation to Atlantic meridional overturning circulation shutdown , 2008 .

[35]  John P. Dunne,et al.  A synthesis of global particle export from the surface ocean and cycling through the ocean interior and on the seafloor , 2007 .

[36]  A. Ridgwell.  Interpreting transient carbonate compensation depth changes by marine sediment core modeling , 2007 .

[37]  V. Brovkin,et al.  Lowering of glacial atmospheric CO2 in response to changes in oceanic circulation and marine biogeochemistry , 2007 .

[38]  Julia C. Hargreaves,et al.  Regulation of atmospheric CO2 by deep‐sea sediments in an Earth system model , 2007 .

[39]  G. Munhoven.  Glacial–interglacial rain ratio changes: Implications for atmospheric CO2 and ocean–sediment interaction , 2007 .

[40]  R. Feely,et al.  Relating estimates of CaCO3 production, export, and dissolution in the water column to measurements of CaCO3 rain into sediment traps and dissolution on the sea floor: A revised global carbonate budget , 2007 .

[41]  J. Hargreaves,et al.  Regulation of atmospheric CO 2 by deep-sea sediments in an Earth system model , 2007 .

[42]  Michele Scardi,et al.  A comparison of global estimates of marine primary production from ocean color , 2006 .

[43]  Andy Ridgwell,et al.  The role of the global carbonate cycle in the regulation and evolution of the Earth system , 2005 .

[44]  C. Hensen,et al.  Organic carbon content in surface sediments—defining regional provinces , 2004 .

[45]  Keith Lindsay,et al.  Upper ocean ecosystem dynamics and iron cycling in a global three‐dimensional model , 2004 .

[46]  Carlo Barbante,et al.  Eight glacial cycles from an Antarctic ice core , 2004, Nature.

[47]  Gokhan Danabasoglu,et al.  A comparison of global ocean general circulation model solutions obtained with synchronous and accelerated integration methods , 2004 .

[48]  M. Joachimski,et al.  Global change in the Late Devonian: modelling the Frasnian–Famennian short-term carbon isotope excursions , 2004 .

[49]  M. Brzezinski,et al.  Silicic acid leakage from the Southern Ocean: A possible explanation for glacial atmospheric pCO2 , 2002 .

[50]  R. Zeebe.  Glacial/interglacial variations in atmospheric CO2 , 2002 .

[51]  Kitack Lee.  Global net community production estimated from the annual cycle of surface water total dissolved inorganic carbon , 2001 .

[52]  S. Wakeham,et al.  A new, mechanistic model for organic carbon fluxes in the ocean based on the quantitative association of POC with ballast minerals , 2001 .

[53]  D. M. Nelson,et al.  A review of the Si cycle in the modern ocean: recent progress and missing gaps in the application of biogenic opal as a paleoproductivity proxy , 2000 .

[54]  E. Boyle,et al.  Glacial/interglacial variations in atmospheric carbon dioxide , 2000, Nature.

[55]  Karline Soetaert,et al.  On the coupling of benthic and pelagic biogeochemical models , 2000 .

[56]  David Archer,et al.  What caused the glacial/interglacial atmospheric pCO2 cycles? , 2000 .

[57]  L. Kump,et al.  CHEMICAL WEATHERING ,A TMOSPHERIC CO 2 , AND CLIMATE , 2000 .

[58]  Christoph Heinze,et al.  A global oceanic sediment model for long‐term climate studies , 1999 .

[59]  A. Gnanadesikan.  A global model of silicon cycling: Sensitivity to eddy parameterization and dissolution , 1999 .

[60]  J. Randerson,et al.  Primary production of the biosphere: integrating terrestrial and oceanic components , 1998, Science.

[61]  Thomas F. Stocker,et al.  A latitude-depth, circulation-biogeochemical ocean model for paleoclimate studies. Development and sensitivities , 1998 .

[62]  Y. Yamanaka,et al.  The role of the vertical fluxes of particulate organic matter and calcite in the oceanic carbon cycle: Studies using an ocean biogeochemical general circulation model , 1996 .

[63]  James C. McWilliams,et al.  Approach to Equilibrium in Accelerated Global Oceanic Models. , 1996 .

[64]  R. Jahnke,et al.  The global ocean flux of particulate organic carbon: Areal distribution and magnitude , 1996 .

[65]  D. Etheridge,et al.  Natural and anthropogenic changes in atmospheric CO2 over the last 1000 years from air in Antarctic ice and firn , 1996 .

[66]  D. M. Nelson,et al.  The Silica Balance in the World Ocean: A Reestimate , 1995, Science.

[67]  C. Lorius,et al.  Vostok ice core provides 160,000-year record of atmospheric CO2 , 1987, Nature.

[68]  W. Broecker,et al.  The role of CaCO3 compensation in the glacial to interglacial atmospheric CO2 change , 1987 .

[69]  H. Oeschger,et al.  Information on the CO2 Cycle from Ice Core Studies , 1980, Radiocarbon.

[70]  J. Norfolk,et al.  Primary Production of the Biosphere , 1976 .

[71]  F. H. Constable,et al.  Silicic Acid , 1947, Nature.