Desarrollo de la Antártica

Víctor T. Neal I INTERNATIONAL SOUTHERN OCEAN STVDIES phosphate, nitrite, and nitrate analysis were taken at discrete depths to near the bottom. The hydrographic work done on MELVILLE in Drake IPassage was designed to determine fue densíty structure and distripution of chemical properties in the vicinity of the current meter array. Qne hydrographic section was made in BransIield Strait and one north– south crossing was made through the western Scotia Sea. This last crossing included 20 closely-spaced (4 to 5 km) stations across the !Polar Frontal Zone. FDRAKE 76 In 1976 two 1>hips were used in F,DRAKE: A.G.S. YELCHO, operated by the Ohilean Navy; and, Rjv THOMAS G. THOMPSON, operated by the Univer&ity oI Washington. ¡Punta IArenas, Chile, was the operating base for 'both ships during FDRAKE 76. The first two legs of the THOMiPSON cruise were designed to obtain spatial and temporal data on the mcsoscale and large-scale variability of the Antarctic Circumpolar Curren t in Drake Passage. Leg 1 was devoted primarily to the recovery of shallow pressure recorders .nd recording current-termperature meters which had been moored during FDRAKE 75 and to the installation oI another long-term array of recording instruments. Efforts to retrieve the shallow presmre recorders installed in 1975 were partialIy successful. The recorder moored off ¡Cape Horn was not retrieved. AH but 1 of the 19 cunent-temperature recorders were retrieved. A new array of JI currenHemperatrUre-pressure recorders was moored at seven locations. Five deep pressure sensors on three recorders were also moored at three locations. Shallow pressure recorders were again moored on the shelves near Cape Horn and Livingstone Island. Pressure recorders were installed to provide informatÍon on the long-term variation in the barotropic component of mass transport through the region. During [;egs 1 and n, hydrographicjsTO stations and STO stations were ta<ken in the Passage and along the east-west trench at the southern end oI tJhe Passage. Studies of the water mass distributions and chemical balances in the area were enhanced by the chelnical data obtained on Leg 1 and Leg u. A computer compatilble Auto Analyzer n was used on board to determine concentrations of phosphate, nitrate, silicate, and nitrite. Four experimental NDBC (National Data Buoy Center) satellite-