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Transient Response of the Southern Ocean to Idealized Wind and Thermal Forcing across Different Model Resolutions.
- Source :
- Journal of Climate; Jul2021, Vol. 34 Issue 13, p5477-5496, 20p, 4 Graphs, 12 Maps
- Publication Year :
- 2021
-
Abstract
- The Southern Ocean has undergone significant climate-related changes over recent decades, including intensified westerly winds and increased radiative heating. The interplay between wind-driven cooling and radiative warming of the ocean is complex and remains unresolved. In this study, idealized wind and thermal perturbations are analyzed in a global ocean–sea ice model at two horizontal resolutions: nominally, 1° and 0.1°. The sea surface temperature (SST) response shows a clear transition from a wind-driven cooling phase to a warming phase. This warming transition is largely attributed to meridional and vertical Ekman heat advection, which are both sensitive to model resolution due to the model-dependent components of temperature gradients. At higher model resolution, due to a more accurate representation of near-surface vertical temperature inversion and upward Ekman heat advection around Antarctica, the anomalous SST warming is stronger and develops earlier. The mixed layer depth at midlatitudes initially increases due to a wind-driven increase in Ekman transport of cold dense surface water northward, but then decreases when the thermal forcing drives enhanced surface stratification; both responses are more sensitive at lower model resolution. With the wind intensification, the residual overturning circulation increases less in the 0.1° case because of the adequately resolved eddy compensation. Ocean heat subduction penetrates along more tilted isopycnals in the 1° case, but it orients to follow isopycnal layers in the 0.1° case. These findings have implications for understanding the ocean response to the combined effects of Southern Hemisphere westerly wind changes and anthropogenic warming. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 08948755
- Volume :
- 34
- Issue :
- 13
- Database :
- Complementary Index
- Journal :
- Journal of Climate
- Publication Type :
- Academic Journal
- Accession number :
- 150664267
- Full Text :
- https://doi.org/10.1175/JCLI-D-20-0981.1