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=  LGM carbon cycle modeling
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= Model:
* Ocean-only offline tracer model based on the MIROC 4m coupled atmosphere ocean general circulation model (AOGCM)


= Data:
* Data format is NetCDF.
* Missing value = -999.


= Simulations:
* Pre-industrial control run (PI_ctl)
* LGM control run (LGM_ctl)
  * This simulation follows the Paleoclimate Modelling Intercomparison Project phase 2 (PMIP2) protocol.
* LGM_strat run
  * This simulation tries to reproduce the glacial deep water properties by making the following two changes from the LGM_ctl run.
    - Salinity restoring toward high salinity at the bottom layer in the Southern Ocean is applied.
    - The vertical diffusion coefficient is set to 0.1 cm2 s-1 in the Southern Ocean (30-90S).
* LGM_glac run
  * This simulation introduces the effect of iron fertilization from glaciogenic dust.
* LGM_so run
  * This simulation considers enhanced salinity stratification in the Southern Ocean (as in the LGM_strat) and iron fertilization from glaciogenic dust (as in the LGM_glac).
* LGM_sed run
  * This simulation considers carbonate sedimentary process in the LGM_ctl.
* LGM_all run
  * This simulation considers carbonate sedimentary process in the LGM_so.

- These simulation results are the same as those reported in Kobayashi et al. 2021.
- For the carbon cycle atmospheric CO2, we ran simulations with freely evolving atmospheric CO2 for the carbon cycle part.
- No change of code between the LGM and Pre-industrial run, only change of boundary conditions.
- For the LGM control run, we did not increase salinity, nutrients and alkalinity to account for the volume change between LGM and PI.
  However, if such an experiment is necessary, it can be done immediately in a similar manner.
- No permafrost
- For the DC13: fixed atmospheric concentration (-6.5 per mille)
- For the DC14: fixed atmospheric concentration ( 0.0 per mille)


= Main Reference:
* Kobayashi, H., A. Oka, A. Yamamoto, A. Abe-Ouchi (2021): Glacial carbon cycle changes by Southern Ocean processes with sedimentary amplification


= Related References:
* Kobayashi, H., A. Abe-Ouchi, and A. Oka (2015): Role of Southern Ocean stratification in glacial atmospheric CO2 reduction evaluated by a three-dimensional ocean general circulation model, Paleoceanography, 30(9), 1202--1216, doi:https://doi.org/10.1002/2015PA002786.
* Kobayashi, H., and A. Oka (2018): Response of atmospheric pCO2 to glacial changes in the Southern Ocean amplified by carbonate compensation, Paleoceanography and Paleoclimatology, 33(11), 1206--1229, doi:https://doi.org/10.1029/2018PA003360.
* Chikamoto, O. M., A. Abe-Ouchi, A. Oka, and R. Ohgaito (2012): Quantifying the ocean's role in glacial CO2 reductions, Clim. Past, 8(2), 545--563, doi:https://doi.org/10.5194/cp-8-545-2012
* Oka, A., A. Abe-Ouchi., M. Chikamoto, and T. Ide (2011): Mechanisms controlling export production at the LGM: effects of changes in oceanic physical fields and atmospheric dust deposition, Glob. Biogeochem. Cycles, 25(2), GB2009, doi:https://10.1029/2009GB003628
* Yamamoto, A., A. Abe-Ouchi, R. Ohgaito, A. Ito, and A. Oka (2019): Glacial CO2 decrease and deep-water deoxygenation by iron fertilization from glaciogenic dust, Clim. Past, 15(3), 981--996, doi:https://doi.org/10.5194/cp-2019-31