interest will focus on the intervening layers, from those just 

 below the surface to 1,000 meters, for these hold the world's 

 substantial stocks of marine creatures, including the tunas. 

 Existing atlases of this marine domain are based on limited 

 amounts of data (less than half the total, at the best) and 

 rest upon methods of analysis relatively insensitive to some 

 of the subtle changes in oceanographic properties. 



Recognizing these needs, Richard A. Barkley of our 

 Laboratory started 5 years ago to prepare such a publica- 

 tion. It has now been completed and is ready for submission 

 to the publishers, so that by 1967, or if all goes well, late 

 1966, there will be available an atlas of the oceanographic 

 properties of the top 5,000 to 6,000 feet of the entire Pacific 

 Ocean, based upon 50,000 oceanographic stations. 



The 3 million observations upon which the atlas draws 

 come from cruises as early as 1906, and as late as December 

 1964. The data have been supplied on punched cards by 

 the National Oceanographic Data Center. They have been 

 analyzed at our Laboratory, by use of the facilities of the 

 University of Ha'waii Statistical and Computing Center for 

 most of the automatic data processing. 



The atlas emphasizes the density structure of the Pacific. 

 This structure is closely related to processes of advection, 

 mixing, and water-mass formation. The atlas contains a 

 series of 135 charts showing properties along the various 

 sigma-t (density) surfaces, with the deepest at about 2,000 

 meters average depth. These charts are arranged by quarter 

 years. In addition, the atlas contains a set of vertical 

 sections that extend across the Pacific from Asia to the 

 Americas, and from about 30° S. to the northern boundaries 

 of the Pacific. Other charts show temperature, salinity, 

 and sigma-t at 10 meters by months and the density of 

 observations at several levels by quarter. 



Examples of the charts are shown in figures 25 and 26. 

 In figure 25 is shown the 25.40 sigma-t surface averaged for 

 January, February, and March throughout the Pacific. The 



lighter lines at the top and bottom of the chart show that 

 this layer reaches the surface level of the water at mid- 

 latitudes (it sinks to more than 1,000 feet off Japan). The 

 surface layer north and south of these lines has water of 

 higher density. Plotted on the chart are the salinity values, 

 which also reflect temperature distributions, since density 

 is a function of temperature and salinity. It is easy to see 

 on this chart the effect of the large rivers of the Pacific 

 Northwest as they p)our into the ocean and decrease the 

 average salinity. Their influence is felt over a good part of 

 the eastern half of the North Pacific Ocean. 



Figure 26 is a vertical section showing average values of 

 salinity and depth reaching from 30° S. to 53° N., from 

 Chile to Canada, along long. 139° W., which runs near the 

 Marquesas Islands. The vertical scale is density, and this 

 accounts for the irregularity of the top line. As the lower 

 panel makes apparent, the density of water above 1,000 

 meters varies c«msiderably ; it is least dense (lightest), 

 depth for depth, at about 10° N. 



The atlas will provide the basis for a number of analytical 

 studies. Two already underway include work on the three- 

 dimensional distribution of mass transport by currents and 

 rates of water-mass formation and dissipation. These and 

 a variety of other related research projects are intended to 

 lead towards a realistic conceptual model of the Pacific 

 Ocean that can be used in computer-simulation experiments 

 to study such factors as diffusion and biological consumption 

 of dissolved oxygen, as well as the response of the ocean 

 currents to changes in the atmosphere. Thus the atlas 

 will have a bearing on a host of studies in fishery biology, 

 as well as constituting a definitive document in the oceanog- 

 raphy of the Pacific. 



Drift Cards and Collecting Nets 

 In addition to the completion of the atlas, which has occu- 

 pied much of the energies of Barkley and his associates 

 during the reporting period, two other projects in oceanog- 



36 



