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1977a. NORPAX ADS report number 1. Scripps Inst. 

 Oceanogr., 75 p. 



1977b. NORPAX ADS report number 2. Scripps Inst. 

 Oceanogr., 35 p. 



Preisendorfer, R. W. 



1977. Most probable eigenvalues of a random covariance 

 matrix. Scripps Inst. Oceanogr., SIO Ref. 77-20, 31 p. 



Royer, T. C. 



1976. A note comparing historical sea surface temperature 

 observations at Ocean Station P, J. Phys. Oceanogr. 6:969- 

 971. 



White, W. B. 



1977a. Annual forcing of baroclinic long waves in the tropi- 

 cal North Pacific Ocean. J. Phys. Oceanogr. 7:50-61. 

 1977b. Secular variability in the baroclinic structure of the 

 interior North Pacific from 1950-1970. J. Mar. Res. 35:587- 

 607. 



White, W. B., and R. A. Wylie, Jr. 



1977. Annual and seasonal maps of the residual temperature 

 in the upper waters of the western North Pacific from 1954- 

 1974. Scripps Inst. Oceanogr., SIO Ref. 77-28, 127 p. 



Wyrtki, K., L. Magarrd, and J. Hager. 



1976. Eddy energy in the oceans. J. Geophys. Res. 81:2641- 

 2646. 



International Southern Ocean Studies (ISOS) 



Global atmospheric and oceanic circulation is of particular 

 interest in the southern ocean, because of the strong and vari- 

 able air-sea exchanges that drive the Antarctic Circumpolar 

 Current System and result in the formation of Antarctic bottom 

 water and intermediate water. Understanding this oceanic- 

 atmospheric circulation is one of the building blocks in a com- 

 prehensive theory of global climate dynamics. 



The data base available to establish the structure of the mean 

 fields of temperature and salinity in the Southern Ocean is large, 

 but distributed widely in space (from 5 to 200 km) and time. 

 In some locations, observations have been made yearly since 

 1928, while other locations have only one observation. The 

 data base on variability and response of these fields and of the 

 velocity field is small. In addition, theoretical studies on the 

 dynamics of the interaction of atmospheric and oceanic cir- 

 culation are few. At present, limited knowledge prohibits con- 

 struction of even a simple model to describe long-term, large- 

 scale variability in the Southern Ocean, let alone models of 

 the interaction of this region with large-scale global circulation. 



The program, International Southern Ocean Studies (ISOS), 

 attempts to improve our understanding of circulation in this 

 region. ISOS draws on current technology and is carried out 

 within the period of the Global Atmospheric Research Program 

 (GARP) and the First GARP Global Experiment (FGGE). 

 Table 7 lists ISOS projects and principal investigators. 



The objectives of ISOS are: 



1. Identify the statistical properties and space-time scales of 

 variability in selected regions of the Antarctic Circumpolar 

 Current System. 



2. Develop and subject to critical test theories of dynamical 

 balance, mixing, and exchange with other oceans. 



3. Develop a basis for understanding the role of the large-scale 

 circulation and air-sea interaction in the Southern Ocean in 

 global climate dynamics. 



These objectives are being met through monitoring and dyna- 

 mics experiments in several regions of the Antarctic Circum- 

 polar Current System; analysis of existing data sets; and numeri- 

 cal, analytical, and laboratory modeling. 



First Dynamic Response and Kinematics 

 Experiment (F DRAKE) 



The first such experiment, entitled F DRAKE, combined a 

 monitoring effort and local experiments. It began in the austral 

 summer of 1974 to 1975 and terminated in December 1977. 

 Earlier issues of IDOE Progress Reports describe F DRAKE 

 objectives and experiments. 



The ideas obtained, or sharpened, as a result of the 

 F DRAKE studies have changed basic concepts of the structure 

 and variability of the Antarctic Circumpolar Current system. 

 Bands of water masses and velocities in the basic circumpolar 

 current have been established, and "rings" have been observed 

 in the polar frontal zone. The feasibility of long-term, current/ 

 temperature meter and pressure gage measurements in the 

 Drake Passage has been demonstrated. 



F DRAKE data sets (now up to 3 years long) have shown 

 significant correlations between the currents across the passage 

 and between currents and surface wind. The data set has per- 

 mitted the most accurate estimate to date of the water transport 

 and its variability in the Drake Passage. In addition, calcula- 

 tions show a poleward heat flux across the passage of a magni- 

 tude consistent with global estimates, and show the importance 

 of baroclinic instability in this region. Fluxes calculated using 

 atmospheric parameterization schemes for baroclinic instability- 

 induced eddy transport agree with observed fluxes. All the above 

 data are crucial to the understanding of the role of the Southern 

 Ocean in global climate dynamics. 



Regional studies in the Bransfield Strait established renewal 

 times for the waters of this basin and its influence on surround- 

 ing waters. A statistical study of all available data from the 

 circumpolar current system set upper limits to the scale of meso- 

 scale turbulence in most parts of the Southern Ocean and its 

 horizontal distribution of intensity. 



Five moorings were left in the Drake Passage for 1978 to 

 continue the time series, which are now 3 years long. Two bot- 

 tom-mounted pressure gages were moored at 500 m on the 

 northern side of the passage; two pressure gages were moored 

 at 500 m on the southern side of the passage. A single current- 

 meter mooring with current meters at 416, 927, and 1,947 m 

 is in the center of the Drake Passage at 59.1°S, 63.76° W. 

 A major experiment, S DRAKE, which may use as many as 30 

 moorings, is planned for 1979 in the Drake Passage. 



38 



