+ 20 



10*8,, tio 

 =8.9 



-10 



-20 



lO'S. 



=-0.7' 



+10. 



PROCESSING PROCEDURES 



no 



15 



200 400 600 



DEPTH IN METERS 



8(JlO 



D=800 



34.20 



34.30 34)40 34 50 34 60 

 5=34.40 SALINITY, 7oo 



34.70 



Figure 17. — Portion of graphs for determining 10^ 6 from temperature, salinity, and depth. A. Lower part — graph for 



10^ 'h, pi upper part — graph for 10' 6(, p. B. Graph for 10'' ^j. /. 



However, if the total speeifif volume in situ is 

 desired, it is obtained by adding tlie standard 

 term and the anomaly, aj,,,,,— as,-,, o. p + 5. 



For calculating the anomaly, graphs or tables 

 may be used, as mentioned above. The term 

 lO^As,, is given in table V. page 41 for values 

 of temperature and salinity (LaFond, 1940) 

 {14)- The other terms 10^5, ,,, and lO'^Sj.p are 

 given in tables VI and VII, respectively. The 

 use of these tables with example is described 

 in section D. 4. Such tables have also been 

 put in graphical form (Sund, 1926) {15); 

 (Callaway, 1950) {W). Figures 17A and 17B 

 show portions of two graphs which are to be 

 used together, one giving lO^Sj.p and 10^5, .p, 

 the other giving lO^Aj.,. 



To obtain sufficient accuracy the graphs should 

 be of such a size that 1 inch along the coordinate 

 axes represents 0.0001 of each of the terms of 

 the anomaly or 0.1 °/oo of salinity. A number 

 of large charts arc required to cover the normal 

 range of the variables. To use the graph of 

 figure 17A, a scale is laid along the line of given 

 depth (e. g., 800 meters), and the distance 

 between the given salinity (34.40%o) and temp- 



erature (4.55° C.) lines is marked. This length 

 is measured against the ordinate scale by 

 placing one mark at one zero point and reading 



the sum of 5s, p and 5,, 



the other scale, or 



bj' marking the other zero point on the paper, 

 thus measuring the sum by a length. Then 

 by means of the graph of figure 17B the point 

 corresponding to the same given salinity 

 (.34.40%o) and temperature (4.55° C.) is found. 

 Tlie length corresponding to 5s.p+5,,p is laid 

 off from this point along the line of constant 

 salinity, from which is read the total specific 

 volume anomaly, 5 = 5s,p + 5(,p-f-As,„ along the 

 ordinate. If, in the example of figure 17, 

 temperature=4.55° C, salinity = 34.40%o, and 

 depth = 800 meters, then 5,,p=S.8, 5j.p=— 0.7, 

 As. ,=80.9, and 5 = 89.0. 



DENSITY AND "SIGMA-T" 



Density (or ma.ss per unit voliune) in situ is 

 the reciprocal of the specific volume in situ, 



ps I p= The density in situ, ps , p, may 



be determined by first calculating the specific 

 volume in situ from the equations and tables 



