Reduced West Antarctic melt rates and winds drive a salinity increase in the Ross Sea via baroclinic waves

Le résumé fourni par la source

Freshening of Antarctic shelf waters over the past five decades has reduced Antarctic Bottom Water (AABW) volume. Several periods of salinity increase have, however, occurred in the Ross Sea, most recently since the mid-2010s. Using a high-resolution ocean-sea ice model, we show that an increase in salinity, comparable to the observed increase since the mid-2010s, is simulated when either a perturbation in coastal zonal winds or meltwater is applied in the Amundsen Sea. These perturbations excite baroclinic coastal trapped waves that propagate to the Ross Sea within 2–3 months. In response to the coastal trapped waves, the coastal current weakens and isopycnals shoal near the coast. This leads to enhanced surface salinity in the western Ross Sea and thereby preconditions the water column for increased AABW formation. These results highlight the response of the Ross Sea to remote changes on fast timescales.

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