Bottom pressure correlations in the South Atlantic

Bottom pressure in the Fine Resolution Antarctic Model (FRAM) shows regions where fluctuations are dominated by small‐scale internal variability of the currents, and are not directly related to the wind. There are often very sharp boundaries between these regions and regions of large scale coherence. Bearing this in mind, the measured coherence of BPR measurements near Tristan da Cunha island in the South Atlantic is taken as evidence that mesoscale variability associated with the Antarctic Circumpolar Current (ACC) reaches further north in the model than in reality. There are many possible reasons for this, but the significant result is that the BPR measurements can provide useful information about the dynamical regime of the deep ocean, which can not be discovered by surface measurements.