75 meters depth farther offshore. The relatively 

 high temperatures suggest that the warm water 

 must flow around Point Barrow from the Chukchi 

 Sea, then directly eastward rather than around the 

 gyre of the Beaufort Sea. Fluctuations in the east- 

 ward extent of this warm Pacific water have been 

 observed. Johnson (1956) noted that the eastward 

 flow of Pacific water was more pronounced in 

 1951 (to 143°W) than in 1950 when its most 

 apparent extension east was only to the Colville 

 River (151°W). 



Data from the deep Beaufort Sea (below 200 m) 

 taken over many years and during all seasons 

 from ice islands (Coachman, 1968) show a re- 

 markable regularity in the vertical distribution of 

 temperature and salinity. According to Coach- 

 man (1968) this implies that a steady state condi- 

 tion exists and that the distribution of observed 

 properties within the Arctic basin is the result of 

 continuing processes within the basin. In general 

 the deep waters of the Beaufort Sea are composed 

 of the following water masses: (1) Atlantic Water 

 (200-250 meters down to 900 meters) and (2) 

 Arctic Bottom Water (900 m to bottom). Atlantic 

 Water is characterized by above zero tempera- 

 tures (0 to 0.5°C) and uniform salinities (34.5 to 

 35.07oo). Coachman and Barnes (1961) show the 

 origin of this water mass to be advection through 

 the Norwegian Sea. Arctic Bottom Water is char- 

 acterized by temperatures below 0°C (—0.3 to 

 — 0.4°C) and uniform salinities in the range of 

 34.93 to 34.997oo. Coachman and Barnes (1961) 

 state that this water mass originates in the Nor- 

 wegian Sea in the winter; however, a small con- 

 tribution comes from the marginal seas in the 

 Arctic. 



The classical account of Nansen (1902) and the 

 recent studies of Coachman and Barnes (1961) of 

 the three basic water masses of the Arctic Ocean 

 are slightly modified for the Beaufort Sea. The 

 boundaries between the three main water types 

 are not as clearly defined in this area as in other 

 parts of the Arctic. The Atlantic layer has lost 

 much of its unique characteristics of temperature 

 and salinity due to mixing but here also Pacific 

 water intrudes between the Arctic upper layer and 

 Atlantic layer. For this reason, there has been a 

 tendency to further subdivide the waters of the 

 Beaufort Sea. This has resulted in considerable 



confusion in the literature owing to vague defini- 

 tions and names given to the intermediate water 

 masses. Rather than confuse the reader by listing 

 the many classifications (e.g., Kusunoki et al., 

 1962) it will suffice to say that in this paper the 

 classical approach will be adhered to. A discus- 

 sion of the processes that have affected the three 

 water masses in the southern Beaufort Sea will be 

 given in a later section (Distribution of Measured 

 Properties). 



The surface circulation of the Beaufort Sea has 

 been derived from summer surface vessel cruises, 

 ice movement, drift of ice islands, and distribu- 

 tion of observed water properties. A generalized 

 chart from the U.S. Navy Hydrographic Office 

 (1956) showing the prevailing surface currents in 

 the Beaufort Sea is presented in figure 4. In 

 general, the surface waters have a clockwise 

 (anti-cyclonic) movement, apparently resulting 

 from the general wind pattern (Sater, 1969). The 

 center of the gyre (80°N, 140°W) coincides with 

 the center of the mean atmospheric pressure an- 

 ticyclone (Campbell, 1965). The currents can 

 show great irregularities and wide day to day 

 variations. Surface current velocities vary from 

 to 10 cm/sec in the northern Beaufort Sea (Tripp, 

 1966). However, under great irregular wind 

 stress current speeds of up to 30 cm/sec have 

 been recorded (Kusonoki et al. , 1962). A marked 

 increase in surface current speed occurs in the 

 northern Beaufort Sea in the summer or fall 

 (Coachman, 1969). This surge occurs in the late 

 summer west of 140°W and not until late fall in 

 the eastern part of the gyre. The fastest surface 

 currents seem to occur in the southwest region of 

 the Beaufort Sea near Point Barrow, Alaska (U.S. 

 Navy Hydrographic Office, 1963) where current 

 speeds of 20 cm/sec are common. 



Movement of the deeper waters in the Beaufort 

 Sea has been inferred from indirect evidence and 

 two conflicting patterns have been reported. 

 Timofeyev (1957) suggested a general cyclonic 

 (counter clockwise) flow for the Atlantic Water in 

 the entire Arctic Ocean. The flow pattern is infer- 

 red from a study of the heat content of the layer. 

 Worthington (1953, 1959) has suggested a differ- 

 ent circulation pattern for Atlantic Water in the 

 Beaufort Sea: anticyclonic flow similar to the sur- 

 face layer. This flow pattern is based on an ex- 



