Desarrollo de la Antártica

EL DESARROLW DE LA ANTÁRTICA figuration; lateral movements up lo 100 km in two to three weeks have been observed. The central core showing the greatest meridional movement. The flows extend below the lower depths of tibe different water masses and are vertically cohtrent to the bottom except in re· gions where large topographic featurcs exÍ&t. a:hese bottom features disrupt the vertical coherence to as much as several hundred meters aboye. Meridional heat exchange across the Antarctic Circumpolar Current system must be large in order to provide the exehanges necessary to modify the surfaee waters to form Autarctic Intermediate Water and Antaretic Bottom Water. asos observations have revealed that mean· ders in the eurrent eores can develop into closed rings. Ring formation represents a meehanism for the exehange of Iheat, salt and momentum aeross the eores within the ACC system. In the Drake Passage regíon, energy penetrates deeply ínto the oeean at frequencies which also show large energy levels in the surface wind. In mid-passage these low frequeney (less than diurnal) motions seem to be vertiealIy coherent throug'hout the water column. The Polar Frontal Zone (the transition zone between the Suban· taretic SuIÍace Water and the Antarctie LSurface Water) displays late– ral interleaving of waters. The "lea'ves" are on the order of 10m thick. The transition zone in the passage !egion has a north to south extent of 200 to 300 km (based on austral summer data) . The northern li· mit of the zone extends over many tens of kilometers while the sOlithcrn limit is only 5 to ,10 km in extent. Within the ACC, year long current reeords separated by 100 - 200 km or more show no significant correlations wlhen the fuIl records are observed at most locatíons dur;ing the austral winter. Analysis of one to three month periods during Ihe austral wínter shows signifi– cant eorrelations in motions observed at separations of 100 km or more, especially near the central eore oC the ACC. Transport through the passage, ealculated by referencing geostrophle transports to 12 eurrent meter meaSUIements of three weeks, yield an average transport of 124 x 10 6 m S /sec to the east. Based on year Ion?; current records it is estimated that the transport may vary about 60 x ,10 6 m 3 jsec froma mean of abotÍt 125 x 10 6 mS/sec. Hydrographic measurements in :B'ransfield Strait reflect the t!hree distinct basins in the strait. Apparelltly bottom water in these basins ls renewed locally about every 10 years. These basin waters do' not significantly effect waters outside the strait below sill depth (about 1100 m) of the basins.