noaa-model-23470 Simulations of glacial climate and ocean biogeochemistry with the CSIRO Mk3L v1.0 Buchanan, P.J.; Matear, R.J.; Lenton, A.; Phipps, S.J.; Chase, Z.; Etheridge, D.M. Simulations of glacial climate and ocean biogeochemistry with the CSIRO Mk3L v1.0 2018-02-27 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/23470 Investigator P.J. Buchanan Investigator R.J. Matear Investigator A. Lenton Investigator S.J. Phipps Investigator Z. Chase Investigator D.M. Etheridge earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOLG - Large-scale meridional overturning in the Global Ocean earth science paleoclimate paleoclimatic modeling barotropic streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,RES earth science paleoclimate paleoclimatic modeling sea ice cover,null,null,fraction,annual,paleoclimatic modeling,null,null,N,ICEMAX - Maximum annual sea ice extent earth science paleoclimate paleoclimatic modeling phosphate,sea water,null,millimole per cubic meter,annual,paleoclimatic modeling,null,null,N,PO4 - Phosphate concentration earth science paleoclimate paleoclimatic modeling calcite saturation state,sea water,null,dimensionless,annual,paleoclimatic modeling,null,null,N,OMEGACA - Calcite saturation state earth science paleoclimate paleoclimatic modeling latitude,null,null,degree north,null,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOLI - Large-scale meridional overturning in the Indian Ocean earth science paleoclimate paleoclimatic modeling surface downward x stress,null,null,pascal,annual,paleoclimatic modeling,null,null,N,SMFZON - Zonal wind stress earth science paleoclimate paleoclimatic modeling surface heat flux,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,STFHT - Surface heat flux earth science paleoclimate paleoclimatic modeling salinity,sea water,null,practical salinity unit,annual,paleoclimatic modeling,null,null,N,SAL - Salinity earth science paleoclimate paleoclimatic modeling oxygen,sea water,null,millimole per cubic meter,annual,paleoclimatic modeling,null,null,N,OXY - Oxygen concentration earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOEP - Eddy-induced meridional overturning in the Pacific Ocean earth science paleoclimate paleoclimatic modeling surface downward y stress,null,null,pascal,annual,paleoclimatic modeling,null,null,N,SMFMER - Meridional wind stress earth science paleoclimate paleoclimatic modeling sea water y velocity,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,V - Meridional velocity earth science paleoclimate paleoclimatic modeling sea ice cover,null,null,fraction,annual,paleoclimatic modeling,null,null,N,ICEAVE - Annual average sea ice extent earth science paleoclimate paleoclimatic modeling alkalinity,sea water,null,millimole per cubic meter,annual,paleoclimatic modeling,null,null,N,ALK - Alkalinity concentration earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOEG - Eddy-induced meridional overturning in the Global Ocean earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOTP - Total meridional overturning in the Pacific Ocean earth science paleoclimate paleoclimatic modeling dissolved inorganic carbon,sea water,null,millimole per cubic meter,annual,paleoclimatic modeling,null,null,N,DIC - Dissolved Inorganic Carbon concentration earth science paleoclimate paleoclimatic modeling aragonite saturation state,sea water,null,dimensionless,annual,paleoclimatic modeling,null,null,N,OMEGAAR - Aragonite saturation state earth science paleoclimate paleoclimatic modeling mixed layer depth,null,null,meter,annual,paleoclimatic modeling,null,null,N,CDEPTHM - Maximum depth of convection earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOEA - Eddy-induced meridional overturning in the Atlantic Ocean earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOTI - Total meridional overturning in the Indian Ocean earth science paleoclimate paleoclimatic modeling sea water x velocity,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,U - Zonal velocity earth science paleoclimate paleoclimatic modeling organic matter,sea surface,null,gram per square meter per year,annual,paleoclimatic modeling,null,null,N,POC - Particulate Organic Matter production at surface expressed as grams carbon earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOTG - Total meridional overturning in the Global Ocean earth science paleoclimate paleoclimatic modeling upward sea water velocity,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,W - Vertical velocity earth science paleoclimate paleoclimatic modeling mineral matter,sea surface,null,gram per square meter per year,annual,paleoclimatic modeling,null,null,N,PIC - Particulate Inorganic Matter production at surface expressed as grams carbon earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOLA - Large-scale meridional overturning in the Atlantic Ocean earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOTA - Total meridional overturning in the Atlantic Ocean earth science paleoclimate paleoclimatic modeling sea ice cover,null,null,fraction,annual,paleoclimatic modeling,null,null,N,ICEMIN - Minimum annual sea ice extent earth science paleoclimate paleoclimatic modeling wind speed,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,WIND2 - Sea surface wind speed squared earth science paleoclimate paleoclimatic modeling potential temperature,sea water,null,degree Celsius,annual,paleoclimatic modeling,null,null,N,TEMP - Potential temperature earth science paleoclimate paleoclimatic modeling iron,sea water,null,micromole per cubic meter,annual,paleoclimatic modeling,null,null,N,FE - Bioavailable iron concentration earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOEI - Eddy-induced meridional overturning in the Indian Ocean earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,sverdrup,annual,paleoclimatic modeling,null,null,N,MOLP - Large-scale meridional overturning in the Pacific Ocean earth science paleoclimate paleoclimatic modeling salinity,sea surface,null,practical salinity unit per second,annual,paleoclimatic modeling,null,null,N,STFSAL - Surface salinity tendency earth science paleoclimate paleoclimatic modeling carbon dioxide,sea surface,null,parts per million,annual,paleoclimatic modeling,null,null,N,PCO2 - Partial pressure of carbon dioxide at surface earth science paleoclimate paleoclimatic modeling longitude,null,null,degree east,null,paleoclimatic modeling,null,null,N,null earth science paleoclimate model ocean model geoscientificInformation 21000 cal yr BP 18000 cal yr BP Complete -90 90 -180 180 Geographic Region Global Global>LATITUDE >LONGITUDE None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Buchanan, P.J., R.J. Matear, A. Lenton, S.J. Phipps, Z. Chase, and D. Etheridge 2016 Climate of the Past 12 12 2271-2295 10.5194/cp-12-2271-2016

The ocean's ability to store large quantities of carbon, combined with the millennial longevity over which this reservoir is overturned, has implicated the ocean as a key driver of glacial–interglacial climates. However, the combination of processes that cause an accumulation of carbon within the ocean during glacial periods is still under debate. Here we present simulations of the Last Glacial Maximum (LGM) using the CSIRO Mk3L-COAL (Carbon–Ocean–Atmosphere–Land) earth system model to test the contribution of physical and biogeochemical processes to ocean carbon storage. For the LGM simulation, we find a significant global cooling of the surface ocean (3.2 °C) and the expansion of both minimum and maximum sea ice cover broadly consistent with proxy reconstructions. The glacial ocean stores an additional 267 Pg C in the deep ocean relative to the pre-industrial (PI) simulation due to stronger Antarctic Bottom Water formation. However, 889 Pg C is lost from the upper ocean via equilibration with a lower atmospheric CO2 concentration and a global decrease in export production, causing a net loss of carbon relative to the PI ocean. The LGM deep ocean also experiences an oxygenation ( > 100 mmol O2 m-3) and deepening of the calcite saturation horizon (exceeds the ocean bottom) at odds with proxy reconstructions. With modifications to key biogeochemical processes, which include an increased export of organic matter due to a simulated release from iron limitation, a deepening of remineralisation and decreased inorganic carbon export driven by cooler temperatures, we find that the carbon content of the glacial ocean can be sufficiently increased (317 Pg C) to explain the reduction in atmospheric and terrestrial carbon at the LGM (194 ± 2 and 330 ± 400 Pg C, respectively). Assuming an LGM–PI difference of 95 ppm pCO2, we find that 55 ppm can be attributed to the biological pump, 28 ppm to circulation changes and the remaining 12 ppm to solubility. The biogeochemical modifications also improve model–proxy agreement in export production, carbonate chemistry and dissolved oxygen fields. Thus, we find strong evidence that variations in the oceanic biological pump exert a primary control on the climate. STUDY NOTES: Simulations of glacial climate and ocean biogeochemistry with the CSIRO Mk3L. This dataset includes both the physical and biogeochemical output of simulations performed with the CSIRO Mk3L v1.2 Earth System Model under broadly Pre-Industrial (PI; 1950 CE) and Last Glacial Maximum (LGM; 21,000 BCE) climates. Two simulations using the fully coupled Earth System Model, with atmosphere, ocean and sea-ice components, were undertaken by forcing the model with the boundary conditions of each climate state. The boundary conditions included appropriate greenhouse forcing using CO2 equivalents and orbital parameters. Climatologies of sea surface temperature, sea surface salinity, and x and y vectors of sea surface wind stresses were produced by both the PI and LGM coupled experiments and were used to force the ocean general circulation model. Additional climatologies of sea ice fractional cover, sea surface wind speeds, and net incident short-wave radiation were important for forcing the biogeochemical model. These climatologies are available. Also available are the three-dimensional global annual averages of oceanic properties for both PI and LGM climates. These include temperature, salinity, oxygen, apparent oxygen utilisation, dissolved inorganic carbon, alkalinity, calcite saturation state, aragonite saturation state, phosphate and iron concentrations. A full description of the CSIRO Mk3L v1.2 can be found in both: Phipps, S. J., Rotstayn, L. D., Gordon, H. B., Roberts, J. L., Hirst, A. C., and Budd, W. F.: The CSIRO Mk3L climate system model version 1.0 - Part 1: Description and evaluation, Geosci. Model Dev., 4, 483-509, doi:10.5194/gmd-4-483-2011, 2011. Phipps, S. J., Rotstayn, L. D., Gordon, H. B., Roberts, J. L., Hirst, A. C., and Budd, W. F.: The CSIRO Mk3L climate system model version 1.0 - Part 2: Response to external forcings, Geosci. Model Dev., 5, 649-682, doi:10.5194/gmd-5-649-2012, 2012. A complete description of the biogeochemical ocean model that was used (Mk3L-COAL) can be found in Appendix A of: Matear, R. J. and Lenton, A.: Quantifying the impact of ocean acidification on our future climate, Biogeosciences, 11, 3965-3983, doi:10.5194/bg-11-3965-2014, Contact: pearse.buchanan@utas.edu.au for any question on the dataset content and provenance paola.petrelli@utas.edu.au for questions or issues with file accessibility Guide to the data files: |Pre-Industrial output| O-PI_GCM.nc = Physical fields for the Pre-Industrial climate PIice.nc = Sea ice concentration fields for the Pre-Industrial climate O-PI.nc = Biogeochemical fields for the Pre-Industrial climate O-PI_LGM-co2.nc = Biogeochemical fields for the Pre-Industrial climate (with atmospheric CO2 set at 185 ppm) O-PI_LGM-sol.nc = Biogeochemical fields for the Pre-Industrial climate (with atmospheric CO2 set at 185 ppm, and surface conditions of the Last Glacial Maximum) O-PI_LGM-ice.nc = Biogeochemical fields for the Pre-Industrial climate (with atmospheric CO2 set at 185 ppm, and sea ice of the Last Glacial Maximum) |Last Glacial Maximum output| O-LGM_GCM.nc = Physical fields for the Last Glacial Maximum climate LGMice.nc = Sea ice concentration fields for the Last Glacial Maximum climate O-LGM.nc = Biogeochemical fields for the Last Glacial Maximum climate O-LGM_BGC-poc.nc = Biogeochemical fields for the Last Glacial Maximum climate (with 10x potential export production) O-LGM_BGC-rem.nc = Biogeochemical fields for the Last Glacial Maximum climate (with increased export of organic matter to depth) O-LGM_BGC-pic.nc = Biogeochemical fields for the Last Glacial Maximum climate (with no production of calcifying organisms) O-LGM_BGC-all.nc = Biogeochemical fields for the Last Glacial Maximum climate (with all above biogeochemical modifications) |Observational datasets used for validation| Levitus_obs.nc = Observations of modern fields from Levitus, Levitus (2001) World Ocean Database, Vol 13, US Department of Commerce, National Ocean and Atmosphere Agency. FIELDS FROM THE GENERAL CIRCULATION MODEL: CDEPTHM - Maximum depth of convection - metres (m) MOEA - Eddy-induced meridional overturning in the Atlantic Ocean - sverdrups (1e6 m3/s) MOEG - Eddy-induced meridional overturning in the Global Ocean - sverdrups (1e6 m3/s) MOEI - Eddy-induced meridional overturning in the Indian Ocean - sverdrups (1e6 m3/s) MOEP - Eddy-induced meridional overturning in the Pacific Ocean - sverdrups (1e6 m3/s) MOLA - Large-scale meridional overturning in the Atlantic Ocean - sverdrups (1e6 m3/s) MOLG - Large-scale meridional overturning in the Global Ocean - sverdrups (1e6 m3/s) MOLI - Large-scale meridional overturning in the Indian Ocean - sverdrups (1e6 m3/s) MOLP - Large-scale meridional overturning in the Pacific Ocean - sverdrups (1e6 m3/s) MOTA - Total meridional overturning in the Atlantic Ocean - sverdrups (1e6 m3/s) MOTG - Total meridional overturning in the Global Ocean - sverdrups (1e6 m3/s) MOTI - Total meridional overturning in the Indian Ocean - sverdrups (1e6 m3/s) MOTP - Total meridional overturning in the Pacific Ocean - sverdrups (1e6 m3/s) RES - Barotropic streamfunction - sverdrups (1e6 m3/s) SMFMER - Meridional wind stress - pascals (N/m2) SMFZON - Zonal wind stress - pascals (N/m2) STFHT - Surface heat flux - Watts per m2 (W/m2) STFSAL - Surface salinity tendency - psu per second (s-1) U - Zonal velocity - metres per second (m/s) V - Meridional velocity - metres per second (m/s) W - Vertical velocity - metres per second (m/s) FIELDS FROM THE SEA ICE MODEL: ICEMAX - Maximum annual sea ice extent - fractional cover per metre squared (m-2) ICEMIN - Minimum annual sea ice extent - fractional cover per metre squared (m-2) ICEAVE - Annual average sea ice extent - fractional cover per metre squared (m-2) FIELDS FROM THE BIOGEOCHMEICAL MODEL: PCO2 - Partial pressure of carbon dioxide at surface - Parts per million (ppm) POC - Particulate Organic Matter production at surface - grams carbon per metre squared per year (g C m-2 yr-1) PIC - Particulate Inorganic Matter production at surface - grams carbon per metre squared per year (g C m-2 yr-1) WIND2 - Sea surface wind speed squared - metres per second (m/s) TEMP - Potential temperature - Celcius SAL - Salinity - PSU OXY - Oxygen concentration - millimoles per cubic metre (mmol/m3) DIC - Dissolved Inorganic Carbon concentration - millimoles per cubic metre (mmol/m3) ALK - Alkalinity concentration - millimolar equivalents per cubic metre (mmol Eq. / m3) PO4 - Phosphate concentration - millimoles per cubic metre (mmol/m3) FE - Bioavailable iron concentration - micromoles per cubic metre (umol/m3) OMEGAAR - Aragonite saturation state - Omega OMEGACA - Calcite saturation state - Omega Provided Keywords: Nitrogen cycle, carbon cycle, Marine ecosystem, Phytoplankton, Carbon dioxide, climate change

GET DATA http://dx.doi.org/10.4225/41/5859eeac6b473 DOI Landing Page; Study Description and Link to the Data on THREDDS Server GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/buchanan2016/ Data Folder; Model description and subdirectory of netCDF data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/buchanan2016/buchanan2016-mk3l-lgm.txt NOAA Template File; CSIRO Mk3L 1.2 v1.0 Glacial Study Metadata USA/NOAA DIF Version 9.8.4 2019-03-12 2019-03-12