Property transport of heat and salt were com- 

 puted for each solenoid in the survey sections 

 using the following equations: 



Q,=Fxr„ 



(5) 



where 



Q,=heat transport °C. m'/sec 

 rm=niean value of the temperature 

 within the solenoid 

 V= volume flow 



and 



where 

 M. 



M,= VXS,nXpn. 



(6) 



salt transport (10*) gms/sec 

 mean value of the salinity within the 

 solenoid 



p„=M' density of seawater 



\^= volume flow 



Equation (5) is not a true heat flow calculation, 

 however this method is representative of the heat 

 and allows intercomparison of the heat flow 

 tlirough the various sections. The mean tempera- 

 tures are arrived at for each solenoid by using a 

 weighted mean obtained from the isotherm distri- 

 bution of the property sections. Equation (6) 

 gives the grams of salt transported through each 

 solenoid. The mean salinity was determined, 

 similar to the mean temperature, by using the 

 salinity distribution sections. A mean density 

 (p,„) of 1.03 gms/cm^ was selected to speed com- 

 putations. Actual densities range from 1.025 

 gms/cm^ to 1.028 gms/cm^. However, the error 

 in rounding to 1.03 gms/cm^ is negligible com- 

 pared to the estimated error of 10 percent for the 

 overall procedure. 



Figures 3 and 4 show the diagrammatic construc- 

 tion of a volume-salt-heat transport section. Each 

 solenoid contains 6 values resulting from the 

 above calculations. These values are: direction 

 of movement, volume flow, mean temperature, 

 mean salinity, heat flow, and salt transport. Tliis 

 allows the sunnning of the data contained in tlio 

 various solenoids according to the desired pi-es- 

 entation or analyzation of the data. For ex- 

 ample; in this paper direction of movement was 

 considered along with particular water character- 

 istics. Solenoids which contained water at a tem- 

 perature of less than 2.0° C. and a salinity of less 

 than 34.3%o were summed. These solenoids are 



emphasized in figures 3 and 4 by solid outlines for 

 southward-moving water and dashed for north- 

 ward-moving water. 



The computer reduction of the volume flow data 

 eliminates the traditional subjective velocity curve 

 drawings and makes the sections more comparable 

 because of their uniformity of treatment. The 

 method is limited by the recognized errors of 

 dynamic height computations in addition to the 

 errors and assumptions included by working in 

 shallow water. It is believed however, that this 

 procedure is as accurate as any indirect method 

 presently in use. 



ISENTROPIC ANALYSIS 



Analysis of surfaces of equal entropy was at- 

 tempted for the area adjacent to the entrance to 

 Hudson Strait. Sigma-t surfaces, although not 

 coincident with true isentropic surfaces, are con- 

 sidered a close approach for purposes of analysis. 

 Kollmeyer (1966), depicted the core of the Lab- 

 rador Current using this method and showed pic- 

 torial differences between presenting isotherms at 

 horizontal depth levels versus presenting them on 

 sigma-t surfaces. The isotherms on the sigma-t 

 surfaces clearly displayed the cold core of the 

 Labrador Current whereas the horizontal isotherm 

 plots showed only a west-to-east temperature 

 gradient. A similar treatment of the data is at- 

 tempted herein, except for the fact that nitrite 

 {NO..-N) data are contoured on the sigma-t sur- 

 faces in lieu of temperature data. In addition, the 

 topography of the sigma-t surface is shown. 



According to Montgomery (1938), the move- 

 ment of the water masses are defined for flow 

 direction by the contours of the property distribu- 

 tion. Nitrites were chosen as tlie property to be 

 contoured because they are independent of the 

 density and the properties which determine den- 

 sity, and form an independent chemical property 

 to examine on the surface. There seems to be some 

 relationship between the maximum nitrite concen- 

 tration and the temperature minimum zones in the 

 area of analysis. Figure 5 shows the depth of 

 location of the temperature minimum and the 

 depth of the nitrite maxinunn. In the areas of the 

 cold cores of the Labrador Current, the nitrite 

 maximum is located well below the minimum tem- 

 perature. In the warmer areas, on the eastern 

 edges near the Labrador Sea and the near-shore 

 water, the minimum temperatures generally coin- 



