Articles | Volume 19, issue 4
https://doi.org/10.5194/os-19-1253-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-19-1253-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Potential artifacts in conservation laws and invariants inferred from sequential state estimation
Carl Wunsch
Department of Earth and Planetary Science, Harvard University, Cambridge, MA, USA
Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX, USA
Patrick Heimbach
Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX, USA
Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA
Institute for Geophysics, University of Texas at Austin, Austin, TX, USA
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Carl Wunsch
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Combinations of observations with dynamical, chemical, etc, models are essential tools for understanding of climate change. By "climate" is meant all of the sub-elements including ocean, atmosphere, ice, et al. A common form of combination arises from sequential estimation theory, a methodology susceptible to a variety of errors that can accumulate through time for long records. Using two simple analogues, many of these errors are identified here, with suggestions for accommodating them.
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This paper examines the oxygen isotope data in several deep-sea cores. The question addressed is whether those data support an inference that the abyssal ocean in the Last Glacial Maximum period was significantly colder than it is today. Along with a separate analysis of salinity data in the same cores, it is concluded that a cold, saline deep ocean is consistent with the available data but so is an abyss much more like that found today. LGM model testers should beware.
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The ECCO v4 non-linear inverse modeling framework and its reference solution are made publicly available. The inverse estimate of ocean physics and atmospheric forcing yields a dynamically consistent and global state estimate without unidentified sources of heat and salt that closely fits in situ and satellite data. Any user can reproduce it accurately. Parametric and external model uncertainties are of comparable magnitudes and generally exceed structural model uncertainties.
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Short summary
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Combinations of observations with dynamical, chemical, etc, models are essential tools for understanding of climate change. By "climate" is meant all of the sub-elements including ocean, atmosphere, ice, et al. A common form of combination arises from sequential estimation theory, a methodology susceptible to a variety of errors that can accumulate through time for long records. Using two simple analogues, many of these errors are identified here, with suggestions for accommodating them.
Amy Solomon, Céline Heuzé, Benjamin Rabe, Sheldon Bacon, Laurent Bertino, Patrick Heimbach, Jun Inoue, Doroteaciro Iovino, Ruth Mottram, Xiangdong Zhang, Yevgeny Aksenov, Ronan McAdam, An Nguyen, Roshin P. Raj, and Han Tang
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Freshwater in the Arctic Ocean plays a critical role in the global climate system by impacting ocean circulations, stratification, mixing, and emergent regimes. In this review paper we assess how Arctic Ocean freshwater changed in the 2010s relative to the 2000s. Estimates from observations and reanalyses show a qualitative stabilization in the 2010s due to a compensation between a freshening of the Beaufort Gyre and a reduction in freshwater in the Amerasian and Eurasian basins.
Carl Wunsch
Clim. Past, 12, 1281–1296, https://doi.org/10.5194/cp-12-1281-2016, https://doi.org/10.5194/cp-12-1281-2016, 2016
Short summary
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This paper examines the oxygen isotope data in several deep-sea cores. The question addressed is whether those data support an inference that the abyssal ocean in the Last Glacial Maximum period was significantly colder than it is today. Along with a separate analysis of salinity data in the same cores, it is concluded that a cold, saline deep ocean is consistent with the available data but so is an abyss much more like that found today. LGM model testers should beware.
G. Forget, J.-M. Campin, P. Heimbach, C. N. Hill, R. M. Ponte, and C. Wunsch
Geosci. Model Dev., 8, 3071–3104, https://doi.org/10.5194/gmd-8-3071-2015, https://doi.org/10.5194/gmd-8-3071-2015, 2015
Short summary
Short summary
The ECCO v4 non-linear inverse modeling framework and its reference solution are made publicly available. The inverse estimate of ocean physics and atmospheric forcing yields a dynamically consistent and global state estimate without unidentified sources of heat and salt that closely fits in situ and satellite data. Any user can reproduce it accurately. Parametric and external model uncertainties are of comparable magnitudes and generally exceed structural model uncertainties.
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Short summary
Data assimilation methods that couple observations with dynamical models are essential for understanding climate change. Here,
climateincludes all sub-elements (ocean, atmosphere, ice, etc.). A common form of combination arises from sequential estimation theory, a methodology susceptible to a variety of errors that can accumulate through time for long records. Using two simple analogs, examples of these errors are identified and discussed, along with suggestions for accommodating them.
Data assimilation methods that couple observations with dynamical models are essential for...