Deep ocean currents detected with satellite altimetry

Overflows of dense and cold bottom water through Denmark Strait and the Faroe Bank Channel are associated with enhanced meso-scale current variability associated with eddies. These fluctuations can be detected through enhanced sea surface height variability in TOPEX/Poseidon and European Remote Sensing ERS-1/2 satellite altimeter data. The increased variability coincides with the overflow plumes and has a maximum about 50 km downstream of the Faroe Bank Channel. In Denmark Strait, enhanced variability extends 150 km downstream from the sill, with a width of 50-100 km. There is good agreement between the variability seen by the different satellites. The satellite-observed variability is also in good agreement with in situ observations of temperature and salinity and output from three-dimensional models of the overflow. Sea surface height data show seasonal variability that may be associated with annual variations of the overflow strength.