Desarrollo de la Antártica

Victor T. Neal I INTERNATIONAL SOUTHERN OCEAN STUOIES Due to prolonged severe sea conditions much of the cruise was spent taking XBl1 casts under the di~ection of Dr. William Emery (Te– xas A&M University) . XBT sections indicated tJhe presence of an eddy at about :51 00 S. The current meters were moored in this area. Six hy– drographic stations were completed between 55°S and Antarctica. Ad– ditional hydrographic casts were planned for the second leg of the cruise. During the cruise two chemical octanographers from iOregon State University (Mr. Stephen Hager and Mr. Sandy Moore) made an ;n– tercomparison of Soviet and U. S analytical techniques as part of the hydrographic w.ork. Iceberg Drift Dr. ¡Paul Tchernia CMuséum Natioll<ll d'Histoire Naturelle, París) has beeo determining the general (:'as[ to west drift of large tabular icebergs along the coast of Antarctica since 1972. Transponders are placed on the icebergs so drift tracks can be determined by sateIlite. Thus far, icebergs have beea tracked for various periods, the longest being 414 days. The greatest travel di&tance of any observed thus lar i5 12600 n. miles. The results of 1Jhe experiments indicate that úhe westward drift tums to the north near 90°E. AH icebergs that have been successfully tracked in this region turned northwal'd between 80 0 E and 100 0 E and tihen apparently were caught in th/:! eastward flow oI the circumpolar current. This U-turn for tracked icebergs has been confined to bet– ween 62°S and 64'oS. SIGNIFlCANT RESULTS Analysis of data from the various [ield programs has yielded several significant results that may be of interest to other groups. They are described below. The region contains several water masses which are separated by sharp boundaries. In the Drake Passage three distinct bands of rela– tively high speed flow are separated by regions of low speed flow (relatively still ,water) . The bands of flow exist between: 1) Suban– tarctic Surface Water and the northern extent of the transition IPolar Frontal Zone; 12) tihe southern boundary of the Polar Frontal Zonf' and the Antarctic Surface Water; and, 3) the Antarctic Surface Water and the Bransfield Strait Water. These streams Ghange in spatial con-