While we may feel certain from 

 previous work that the GEK is giving an in- 

 dication of real water motions, these motions 

 are apparently largely of a transient or inertial 

 character and are difficult to relate meaning- 

 fully to other data observed on the cruise. 



DISTRIBUTION OF PROPERTIES 



Temperature 



The temperature cross sections 

 (figs. 24-33) were constructed from bathyther- 

 mograph observations taken at approximately 

 30-mile intervals. The plots of the surface 

 temperatures above each cross section repre- 

 sent "bucket" temperatures from BT stations 

 supplemented by reference to recording ther- 

 mograph traces. These north-south profiles 

 were then used to construct the horizontal plot 

 of the surface temperature (fig. 34). 



The surface temperature plot 

 depicts only the gross features of the tempera- 

 ture field. Thermograph records (see fig. 35 

 for an example) show that the general decrease 

 in temperature from south to north occurred in 

 a series of steplike drops. These drops were 

 usually less than 1 F. , but occasionally were 

 as large as 4 F. Frequently they occurred so 

 rapidly that they appear as vertical lines on 

 the thermograph traces. The thermograph 

 records also show a large number of fluctua- 

 tions superimposed on the general trend. These 

 were generally of less than 1 F. but occasion- 

 ally attained an amplitude of 3. 5 F. A careful 

 check of the bucket temperatures against the 

 thermograph showed these variations were not 

 the result of temperature changes in the engine- 

 cooling water intake, where the sensitive unit 

 of the thermograph was located, except when 

 the engines were stopped. The stopping of the 

 engines produced such distinct patterns that 

 there was no possibility of confusing them with 

 the fluctuations in the surface temperature. 

 The fluctuations in the surface temperature 

 varied in horizontal extent from those which 

 were so small that they could barely be dis- 

 tinguished from the oscillations caused by the 

 roll and vibration of the vessel to the large 

 ones that embraced two or more BT casts, 

 and which are incorporated in the temperature 

 profiles. 



When the variability of the winds, 

 the season of the year, the geographical position 

 of the area, and the geostrophic currents are 

 considered, the complexity of the temperature 

 field is quite comprehensible. Similar varia- 

 tions observed in other areas (Saelen 1952, 



Mackintosh 1946) seem to be associated withone 

 or more of the following phenomena: large 

 horizontal velocity gradients (shear zones), up- 

 welling, convergence, and winter conditions in 

 the middle and higher latitudes. 



The general configurations of the 

 surface isotherms (fig. 34) were consistent with 

 the geostrophic currents (fig. 17). The isotherms 

 which are continuous from east to west are rough- 

 ly parallel to the dynamic height contours. The 

 tonguelike pattern of the isotherms in the anti- 

 cyclonic eddies centered on 145 W. longitude is 

 characteristic of this type of circulation 

 (Sverdrup and Fleming 1941). Many of the warm 

 and cold cells occurred in areas of relatively 

 large horizontal temperature gradients. For 

 example, the cold cell of less than 62 F. cen- 

 tered at 32 30'N. on 160 W. is on the northern 

 side of an area having relatively high velocities 

 and where the curvature of the dynamic height 

 contours is cyclonic. 



An example of the effect of local 

 wind mixing is illustrated by the tongue of less 

 than71°F. at approximately 23°N. , 163°W. The 

 weather data (figs. 5 and 6) show that two cold 

 fronts with winds of over 30 knots had passed 

 over the area in rapid succession just before the 

 observations were made. 



Charts of mean monthly surface 



temperatures (U. S. Navy Hydrographic Office 



1944, Robinson 1951) show a large seasonal 



shift of the mean position of the isotherms in the 



cruise area. For example, the mean position of 



° o 



the 65 F. isotherm on 150 W. shifts from 



42°15'N. in August to 30°15'N. in March. This 

 indicates either that normal winter cooling, be- 

 cause of differences between the air and sea 

 temperature, continues through March or that 

 the flow through or into the area has a sufficiently 

 large southerly component to offset the heating 

 due to increased radiation. 



The air temperatures observed at 

 each bathythermograph station were plotted on 

 the temperature cross sections (figs. 24-33) to 

 ascertain whether there was any consistent dif- 

 ference between the air and sea temperatures. 

 The plots show that the air over the southern part 

 of the area was cooler than the water for the 

 most part but that changes in the air circulation 

 frequently reversed the gradient. The only area 

 where the air was consistently warmer than the 

 water was in the extreme north and in the area 

 between 149 W. and 153 W. , where the geostro- 

 phic flow (fig. 17) was southeasterly. This tem- 

 perature difference indicates that at least some 

 of the small surface temperature changes were 



