Desarrollo de la Antártica

EL DESARROLLO DE LA ANTÁRTICA tracked surface drifters were launched from 11HOMPSON. AH were functioning and being received by satellite prior to launohing. How– ever, none of them produced data for more filian 14 days after launch. R./v THOMPSON and the Soviet research vessellPROFESSOR VIESE made a rendezvous near Livingston IIsland. VIESE was malking current measurements and :hydrographicjsTl> observations to fue west of THOMPSON activities. At rendezvous salinity, oxygen and nutrient standards were exchanged and ~imultaneous hydrographic and STD measurements were made for interc:Jlibration. The third leg of lhe THOMPSON cruise was devoted to a detailed study of the dynamics of the Polar Front under the direction of Dr. Terrence joyce, Woods Hale Oceanographic Institution, Woods Hole, Massachusetts 02543. Vertical velocities in the frontal zone were mea– sured with a guided "free faU" profiling current meter. Two current meters and eleven bead thermistor chains, which had been moored during Leg I as the upper portian oí one of the long-term moorings were recovered as planned. Continuous high resolution profi!es of dissolved oxygen were made at over 100 stations. XBT's were used for mapping the thermal struc– ture and interleaving along fue frollt. 'Light scattering as a function of scattering angle was measured at discrete depths and at a fixed angle in continous profiles from the surface to 1000 m. Light trans– mission was also measured at 11 stations. (Light measurements were carried out by Dr. Kullenberg, University of Co'penhagen). As on Legs I and n, water samples were analyzed for nutrient concentrations. Samples were also obtained for hydrogen and oxygen isotope analysis. This work was dosely supported by work on YELGHO, under the direction of Mr. Hellmuth Sievers, Instituto Hidrográfico de la Ar– mada de Chile and Mr. Steve Patterson, Texas A&:lM' University. YELCHO cruises were designed to delineate and measure the large. scale thermal structure of lhe Polar l"rontal Zone in Drake Passage. 5-71 XBT's were used for this work, and the data were provided in– mediately to scientists on R/V THOMPSON (Leg m) studying the small– scale structure of the frontal zone. Excellent communication between ships and to U. S. shore stations WJ3 made possible through use of the Applied rrechnology Satellite 1) with permission and assistance from the U. S. National Aeronamic'i and Space Administration (NAo SA) • The work of YELeHO was concentrated in the area 58°W to 62QW and 5606: to 59 0 S. The XBT meaSll,:emcnts were made mostly along 3 12