In spite of these limitations, oceanographic interpretations 

 presented here probably are valid because they concern quasi-permanent, 

 large-scale oceanographic features. 



B. The Laptev Sea. 



Temperatures and salinities observed in the Laptev Sea during 

 the NORTHWIND survey revealed a high degree of stratification, with 

 temperatures increasing vertically from the bottom and toward the 

 Siberian coast and salinities decreasing vertically from the bottom 

 and toward the coast. 



Water characterized by two general temperature-salinity relationships 

 was observed during August and September 1963. Water in the northern 

 Laptev and that below 20 meters on most oceanographic stations had 

 salinities from 28.5 to 33.5 %o and temperatures from -1.5 to -1.8"C. 

 Water near the surface in the southern Laptev Sea showed a broader 

 range of higher temperatures and lower salinities than that in the 

 north. Observed temperatures ranged from 0° to over 3'C and observed 

 salinities ranged from slightly over 2 to 28 %„ . These relatively 

 high temperatures and low salinities are attributable to effluent 

 from the five large rivers that empty into the Laptev Sea. 



Distribution of Lena River effluent was best evident in 1963 

 on the basis of observed salinity distribution although it also was 

 apparent in observed temperature distribution. The Lena River fluvial 

 plume, as defined on the basis of both temperature and salinity, 

 appeared to extend in a north to northeasterly direction from the 

 river delta. Lateral plume extent in the Laptev Sea was limited 

 almost entirely to the region between the Lena River Delta and the 

 New Siberian Islands. 



Vertical distribution of the low-salinity, high-temperature water 

 was limited to the upper 15 meters in the form of a rough wedge. 



Offshore circulation and prevailing winds probably are effective 

 in governing distribution of effluent water in the Laptev Sea, but 

 their relative importance is unclear. Available current information 

 is insufficient to permit adequate evaluation of current effects, 

 but good correlation was noted between surface wind directions observed 

 during oceanographic station occupation and the apparent distribution 

 of low density effluent water. 



The extent of Khatanga and Anabar River runoff was evident primarily 

 in observed salinity distribution. The combined fluvial plume from 

 the two rivers, as indicated by salinity distribution, extended in 

 a northeasterly direction from the Khatanga River Estuary at the 

 time of the survey. Vertical distribution of this low-salinity water 

 appeared limited to the upper 10 meters. 



42 



