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Abstract:
Ocean heat transport towards Antarctica directly drives the melting of Antarctic ice shelves, modulating sea level rise and the formation of Antarctic Bottom Water. A common dynamical assumption is that heat transport across the Antarctic continental slope is modulated by the strength of the Antarctic Slope Current (ASC), which is thought to act as a barrier to cross-slope heat transport. However, observations of the ASC are too scarce to investigate its relationship to poleward heat transport across large circumpolar spatial scales, or over long temporal scales. Also, until recently, ocean models lacked the spatial resolution required to accurately represent the ASC or the eddy heat transport onto the Antarctic shelf. In this study, we analyze the relationship between the ASC and the cross-slope heat transport in a circumpolar, eddy-rich ocean and sea ice simulation. We find that the local strength of the time-mean ASC is not a good predictor of local cross-slope heat transport, i.e., spatial variability in the ASC is not related to spatial variability in poleward heat transport. However, there is a relationship between ASC strength and cross-slope heat transport in the temporal domain. We quantify the strength of the relationship across different time scales (sub-seasonal, seasonal and interannual) and across varying model resolution (from 1/10º to 1/20º to 1/40º).
