Contrasting Southern Ocean Sea Level Responses to Surface Flux Changes in Eddy-Rich and Eddy-Parameterized Climate Model Configurations

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Erscheinungsjahr:
2024
Medientyp:
Text
Schlagworte:
  • Climate change
  • Eddies
  • Forcing
  • Model comparison
  • Sea level
  • Southern Ocean
  • Ocean currents
  • Tropics
  • Wind stress
  • Eddy
  • Forcings
  • Fresh Water
  • Halosteric sea level
  • Model inter comparisons
  • Models comparisons
  • Parameterized
  • Southern ocean
  • Surface flux
  • Thermosteric sea level
  • climate change
  • climate forcing
  • climate modeling
  • comparative study
  • eddy
  • parameterization
  • sea level
  • surface flux
Beschreibung:
  • The impact of ocean model resolution on sea level projections in the Southern Ocean is investigated using eddy-rich (ER) and eddy-parameterized configurations of the Max Planck Institute Earth System Model under the Shared Socioeconomic Pathway (SSP) 5-8.5 scenario. We employ the Flux-Anomaly Forced Model Intercomparison Project (FAFMIP) experiment}heat, stress, and freshwater perturbations}at both resolutions to pinpoint the sources of these differences. South of 558S, we found that the changes in thermosteric and halosteric sea levels vary substantially between resolutions due to different responses to freshwater perturbations. In the eddy-parameterized model, the resulting increase in stratification suppresses the mixing of salt and heat from the Circumpolar Deep Water with surface layers. These cause differences in the response of surface fluxes and meridional transports yielding an increase in thermosteric sea levels and a decrease in halosteric sea levels. In the eddy-rich configuration, the main driver of eddy-induced warming and salinification between 408 and 448S is wind stress perturbations. The efficiency of direct eddy effects in ER is restricted to small areas such as the Agulhas Retroflection, the Brazil–Malvinas confluence zone, the Tasman Sea, and, to some extent, the Antarctic Circumpolar Current (ACC). Contrary to expectations, ACC transport increases in the eddy-rich model while decreasing in the eddy-parameterized model under the SSP5-8.5 scenario. FAFMIP results reveal that this decrease is a result of the overcompensation of wind-induced changes by freshwater flux forcing. These results underscore the critical importance of high-resolution models for capturing the processes in sea level projections in the Southern Ocean and beyond. © 2024 American Meteorological Society.
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  • info:eu-repo/semantics/openAccess
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Forschungsinformationssystem der UHH
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oai:www.edit.fis.uni-hamburg.de:publications/293d462a-14d4-4285-8301-9e7c6d85d5d9