An Ensemble Kalman Filter multi-tracer assimilation: Determining uncertain ocean model parameters for improved climate-carbon cycle projections

Gerber, Markus; Joos, Fortunat (2013). An Ensemble Kalman Filter multi-tracer assimilation: Determining uncertain ocean model parameters for improved climate-carbon cycle projections. Ocean Modelling, 64, pp. 29-45. Elsevier 10.1016/j.ocemod.2012.12.012

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An Ensemble Kalman Filter is applied to assimilate observed tracer fields in various combinations in the Bern3D ocean model. Each tracer combination yields a set of optimal transport parameter values that are used in projections with prescribed CO2 stabilization pathways. The assimilation of temperature and salinity fields yields a too vigorous ventilation of the thermocline and the deep ocean, whereas the inclusion of CFC-11 and radiocarbon improves the representation of physical and biogeochemical tracers and of ventilation time scales. Projected peak uptake rates and cumulative uptake of CO2 by the ocean are around 20% lower for the parameters determined with CFC-11 and radiocarbon as additional target compared to those with salinity and temperature only. Higher surface temperature changes are simulated in the Greenland–Norwegian–Iceland Sea and in the Southern Ocean when CFC-11 is included in the Ensemble Kalman model tuning. These findings highlights the importance of ocean transport calibration for the design of near-term and long-term CO2 emission mitigation strategies and for climate projections.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Physics Institute > Climate and Environmental Physics
08 Faculty of Science > Physics Institute

UniBE Contributor:

Gerber, Markus and Joos, Fortunat

Subjects:

500 Science > 530 Physics
500 Science > 550 Earth sciences & geology

ISSN:

1463-5003

Publisher:

Elsevier

Language:

English

Submitter:

Doris Rätz

Date Deposited:

25 Sep 2014 12:25

Last Modified:

10 Sep 2015 10:22

Publisher DOI:

10.1016/j.ocemod.2012.12.012

BORIS DOI:

10.7892/boris.47703

URI:

https://boris.unibe.ch/id/eprint/47703

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