the velocity profile. These will be noted as the description proceeds. 



A caution at this point deals with the spurious salinity spikes. 

 These do introduce relatively small anomalies into the sound-velocity 

 profile. To determine if a salinity anomaly is spurious, it is useful to 

 look at the density curve which should be responsive principally to the 

 salinity. It is likely that only very small density inversions are real, 

 so notable density inversions are indicators of spurious salinity inver- 

 sions. Temperature- induced salinity errors also may exist without form- 

 ing inversions. These are not so obvious but they are of lesser conse- 

 quence because they have minor effects on sound-beam distortion. 



Conditions like those at Station 46 continue through Station 

 44 with slight surficial cooling and perhaps through Station 43 ( no near- 

 surface data) , but at Station 42 (Fig. 13) cooling at the surface begins, 

 mesocale structure begins to show above the thermocline and just below 

 the thermocline and a distinctive nose appears in the temperature profile 

 as a result of the surficial cooling. Station 41 is like 46, but at Station 

 40 (Fig 14) the thermocline has become thicker and less sharp and has 

 taken on some structure. The effect of being closer to the ice is seen 

 in Stations 50, 54, and 56 (Figs. 15-17): a weakening of thermocline 

 (in 50) , cooling at the surface with the formation of a nose (54 and 56) , 

 and the development of a little structure. 



In Station 54 is seen the result of patching in the data from the 

 RS5 near the surface. Near the top of the STD trace the salinity has been 

 distorted by the temperature gradient and the inversion in sigma-t is not 

 real. 



The temperatures in the series of stations 61, 63, 65, 66, and 

 68 are shown nested in Figure 18. These are plotted with the curves 

 spaced 1°C apart and with north on the left because there is less cross- 

 ing of curves in that arrangement. The bottom temperature and the station 

 number appear at the bottom of each curve. The first two of these (Sta. 

 61 and 63) show discrete RS5 data and give little information about 

 mesoscale structure. Proceeding to the north into the ice several things 

 happen simultaneously. The surface cools and the cooling extends 

 deeper until the warm nose which first forms is only a residue of the 

 lower edge of the warm layer. A deep mixed layer at -1 . 1°C appears in 

 Station 65 and at Station 66 all of the deep water is colder than -1.5°C 

 and a still colder layer intrudes between 35 and 60 meters. At Station 

 68 the deeper water is notably warmer, -1 .3°C; the intruding cold layer 

 with temperature as low as -1.67°C is still present, but thinner. Con- 

 siderable temperature structure is present at Stations 65 and 66. It 

 may also be present at Station 63 and in the upper portion of Station 68 

 whose surface temperature is recorded as 0.3°C, 1.4 C warmer than at 

 15 meters. 



24 



