Ocean carbon sink assessment via temperature and salinity data assimilation into a global ocean biogeochemistry model

Bunsen, Frauke; Hauck, Judith; Torres-Valdés, Sinhué; Nerger, Lars

doi:https://doi.org/10.5194/os-21-437-2025

Articles | Volume 21, issue 1

https://doi.org/10.5194/os-21-437-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/os-21-437-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 21, issue 1

Research article

|

13 Feb 2025

Research article |

| 13 Feb 2025

Ocean carbon sink assessment via temperature and salinity data assimilation into a global ocean biogeochemistry model

Frauke Bunsen, Judith Hauck, Sinhué Torres-Valdés, and Lars Nerger

Data sets

Assessing the ocean carbon sink: Assimilation of temperature and salinity into a global ocean biogeochemistry model Frauke Bunsen https://doi.org/10.5281/zenodo.11495081

Global Ocean OSTIA Sea Surface Temperature and Sea Ice Analysis EU Copernicus Marine Service Information (CMEMS) https://doi.org/10.48670/moi-00165

ESA Sea Surface Salinity Climate Change Initiative (Sea_Surface_Salinity_CCI): Weekly and Monthly Sea Surface Salinity Product, v03.21, from 2010 to 2020 Jacqueline Boutin et al. https://doi.org/10.5285/5920a2c77e3c45339477acd31ce62c3c

EN4 quality controlled subsurface ocean temperature and salinity profiles and objective analyses (EN.4.2.2) Met Office https://www.metoffice.gov.uk/hadobs/en4/

OSI SAF Global Medium Resolution Sea Ice Concentration Climate Data Record 2002-2020 (v3.0) EUMETSAT https://doi.org/10.15770/EUM_SAF_OSI_0015

Mixed layer depth climatology computed with a density threshold criterion of 0.03kg/m3 from 10 m depth value Clément de Boyer Montégut https://doi.org/10.17882/91774

Near-surface velocity climatology for the global ocean from drifter observations Lucas C. Laurindo et al. https://doi.org/10.7266/N7SJ1HN5

input4MIPs.CMIP6.OMIP.MRI.MRI-JRA55-do-1-3 Version v1.5.0.1 Hiroyuki Tsujino et al. https://doi.org/10.22033/ESGF/input4MIPs.2205

Supplemental data of Global Carbon Budget 2023 (Version 1.1) Global Carbon Project https://doi.org/10.18160/gcp-2023

RECCAP2-ocean data collection Jens Daniel Müller https://doi.org/10.5281/zenodo.7990823

Surface Ocean CO2 Atlas Database Version 2023 (SOCATv2023) (NCEI Accession 0278913 Dorothee C. E. Bakker et al. https://doi.org/10.25921/r7xa-bt92

A new global interior ocean mapped climatology: the 1° x 1° GLODAP version 2 from 1972-01-01 to 2013-12-31 (NCEI Accession 0286118) Siv K. Lauvset et al. https://doi.org/10.3334/cdiac/otg.ndp093_glodapv2

Global Ocean Data Analysis Project version 2.2023 (GLODAPv2.2023) (NCEI Accession 0283442) Siv K. Lauvset et al. https://doi.org/10.25921/zyrq-ht66

ESA Ocean Colour Climate Change Initiative (Ocean_Colour_cci): Version 5.0 Data Shubha Sathyendranath et al. https://doi.org/10.5285/1dbe7a109c0244aaad713e078fd3059a

SRS Satellite Contributed Ocean Colour - SeaWIFS Chlorophyll Concentration in the Southern Ocean: Monthly, Johnson et al 2013 Robert Johnson et al. https://catalogue-imos.aodn.org.au/geonetwork/srv/eng/catalog.search#/metadata/10fcb776-d331-4a04-ac1f-4a48fa050385

SRS Satellite Contributed Ocean Colour - MODIS - Aqua Chlorophyll Concentration in the Southern Ocean: Monthly, Johnson et al 2013 Robert Johnson et al. https://catalogue-imos.aodn.org.au/geonetwork/srv/eng/catalog.search#/metadata/ce859887-bdf0-4eb0-acf2-80d38af4c85c

Model code and software

Assessing the ocean carbon sink: Assimilation of temperature and salinity into a global ocean biogeochemistry model Frauke Bunsen https://doi.org/10.5281/zenodo.11495274

Short summary

Computer models are often used to estimate the ocean's CO₂ uptake due to a lack of direct observations. Because such idealized models do not match precisely with the real world, we combine real-world observations of ocean temperature and salinity with a model and study the effect on the modeled air–sea CO₂ flux (2010–2020). The corrections of temperature and salinity have their largest effect on regional CO₂ fluxes in the Southern Ocean in winter and a small effect on the global CO₂ uptake.