US/USSR BERING 

 ANADYR 



■88 



LU 

 CC 

 D 

 I- 

 < 



cr 



UJ 



d 



LU 



31 32 



SALINITY (ppt) 



Fig. 2a. All CTD data (l-m average values) from the Gulf of Anadyr and 

 Anadyr Strait stations, and Station 6 from the Bering Slope Current. 



Localized sources of dilution, the main source of freshwater 

 being the Anadyr River entering midway along its western 

 boundary , contribute to the spread in salinity values. Horizontal 

 mixing of waters of the surface layer is evidently small. 



Bottom water values, on the other hand, are bunched much 

 more tightly and cluster into two groups. One grouping is of 

 cold water, <0°C, in the salinity range -32 to 32.7 ppt. The 

 second group is wanner, ~0 to 2°C, and more saline, 32.7 to 

 33.3 ppt. When the spatial distribution of these stations is 

 examined (cf . Frontispiece ), we see that the stations of the cold, 

 lower S group are all from the middle of the gulf, centered 

 around Stations 1 8 and 1 9, while the stations with warmer and 

 more saline deep water are from around its perimeter, including 

 Stations 12. 13 through 25. 26, 29, 31. and 33 to 38. 



Temperatures and salinities of the waters beneath the 

 surface layer are conservative and are modified only through 

 vertical and horizontal (lateral) mixing as the water masses 

 transit the gulf. To expose the source water characteristics and 

 their modifications within the gulf. Fig. 2b plots stations 

 representative of each key water mass and location. The 

 extreme of cold, lower salinity water is represented by Stations 

 18 and 19, from the central gulf. The temperatures are only 

 about 0.1 to 0.2°C above freezing. This water is that of the 

 "cold center" of the Bering Sea, identified already by Barnes 

 and Thompson (1938). The water entering the gulf as the 

 Anadyr Current is represented by Stations 12 and 13 close tp 

 Cape Navarin. This water is from the Bering Slope Current 

 (Station 6), which is the source of highest salinity water to the 

 gulf; the source level lies in the depth range -50-200 m of the 

 current. When the water mass enters the gulf off Cape Navarin. 

 its characteristics are T ~ 1 to 2°C, S - 32.5 to 33 ppt. Thus, its 

 propeilies have already been significantly modified in the 

 1 50 km transit across the shelf from the continental slope, not 

 through surface exchange but through mixing with colder and 

 less saline shelf water — the deep layers have been cooled - 1 .5 

 to 2°C and freshened -0.5 ppt. 



CL 



1- 

 < 



cr 



UJ 



-1 - 



GULF OF ANADYR 



CAPE NAVARIN 



■18 1 BERING SHELF 

 19 I COLD CORE CENTER 



I I L 



32 



33 



34 



SALINITY 



Fig. 2b. T/S diagram of key stations from the Gulf of Anadyr; solid arrows 

 indicate directions of major modifications. Most surface layer values 

 arc not plotted. Water flowing north through Anadyr Strait is created 

 from Bering Slope Current water by mi.xing with cold Bering Shelf 

 water. The interaction is a two-stage process, first lateral layering 

 (cf Station 29) followed by vertical mixing. 



This water mass then circumnavigates the perimeter of the 

 Gulf of Anadyr following the bathymetric contours and 

 interacting with water of the "cold center" enroute. The 

 interaction is in two stages. First is a horizontal layering, or 

 interleaving, of the less dense "cold center" water laterally 

 above the denser water from the Bering Slope Current ( now the 

 Anadyr Current). Station 29, halfway around the gulf, cleariy 

 illustrates this stage of the interaction. Then vertical mixing 

 becomes more effective, particulariy as the water masses are 

 required to shoal to 50 m as they enter Anadyr Strait, and the 

 result is homogenization into narrow ranges of T and S. When 

 the water exits the gulf through Anadyr Strait it has essentially 

 median values of T and S (Stations 39. 40). The two-stage 

 interaction, layering followed by effective vertical mixing, 

 conforms precisely with the model of water mass modification 

 in the gulf proposed by Coachman et al. (1975). 



Chirikov basin 



All CTD data from the Chirikov basin, including Stations 

 39^3 from Anadyr Strait and 76-86 from Bering Strait, are 

 shown in Fig. 3a. There is a concentration of bottom water 

 values with temperatures -1 to 3°C in the S range 32.2 to 

 32.9 ppt. From these values, the remainder trend toward 



30 



