V. PHYSICAL PROPERTIES 



Below a depth of 200 meters, all physical oceanographic factors 

 showed remarkably constant values. This also was true of the water 

 above 200 meters throughout the winter and until mid-December. Fol- 

 lowing this date, pronounced micro-changes appeared in all physical 

 factors, commencing in the upper levels and spreading progressively 

 into the waters above 200 meters. The greatest stratification was 

 observed on 10 January 1961. 



The reasons for these changes, which produced stratification 

 from a condition of very uniform vertical distribution, are dis- 

 cussed under the individual factors. These include increased 

 solar energy absorption, rising air and water temperatures, and 

 inflow of foreign water masses. During the entire period of 

 observation (May 1960 to early March 1961), the area was ice- 

 covered, the nearest open water never being closer than 3 or 4 

 miles. On 10 March 1961, following a strong gale, the ice broke 

 out rapidly throughout the region taking the icehole hut with it, 

 and thus all observations were terminated. (Plate XXX). It is 

 expected that removal of the 2-year old ice cover also produced 

 changes in the values of physical oceanographic factors, in the 

 upper waters, at least. 



A. Temperature 



At depths below 200 meters, water temperatures were very con- 

 stant at any particular level. (Table 1). This also is shown in 

 Figure 2. Table 2 gives the ranges for temperature at different 

 depths at the icehole during the period May through November for 

 winter observations and from November to March for summer observa- 

 tions, and also emphasizes the remarkable uniformity in the lower 

 two-thirds of the water column. Although surface temperatures were 

 taken 1 meter below the surface, being within the metal encased 

 icehole, they represent less the actual conditions than the condi- 

 tion of the heat in the hut during the days prior to each observation; 

 they were very variable. 



Commencing in mid-December, there was a sudden upward trend in 

 water temperatures above 100 meters and, by January, this had ex- 

 tended downward to the 200 meter level (Fig. 2). Maximum stratifi- 

 cation was reached at the 10 January observation and is shown 

 graphically in Figure 3. By comparison, a mid-winter vertical 

 profile, shown in Figure 4, is very uniform. Following the time 

 of maximum stratification, the water above 30 meters dropped in 

 temperature but, below this depth, temperatures down to the 200 

 meter level continued to rise until well through February. The 



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